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The Tsunami-HySEA model is used to perform some of the numerical benchmark problems proposed and documented in the “Proceedings and results of the 2011 NTHMP Model Benchmarking Workshop”. The final aim is to obtain the approval for Tsunami-HySEA to be used in NTHMP projects. Therefore, this work contains the numerical results and comparisons for the five benchmarks problems (1, 4, 6, 7, 9) required for such aim. This set of benchmarks considers analytical, laboratory and field data test cases. In particular, the analytical solution of a solitary wave runup on a simple beach, and its laboratory counterpart, two more laboratory test: the runup of a solitary wave on a conically-shape island and the runup onto a complex 3D beach (Monai
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Performance Benchmarking of Tsunami-HySEA Model for NTHMP’s Inundation Mapping
Activities
JORGE MACI
´AS,
1
MANUEL J. CASTRO,
1
SERGIO ORTEGA,
2
CIPRIANO ESCALANTE,
1
and JOSE
´MANUEL GONZA
´LEZ-VIDA
3
Abstract—The Tsunami-HySEA model is used to perform
some of the numerical benchmark problems proposed and docu-
mented in the ‘‘Proceedings and results of the 2011 NTHMP Model
Benchmarking Workshop’’. The final aim is to obtain the approval
for Tsunami-HySEA to be used in projects funded by the National
Tsunami Hazard Mitigation Program (NTHMP). Therefore, this
work contains the numerical results and comparisons for the five
benchmark problems (1, 4, 6, 7, and 9) required for such aim. This
set of benchmarks considers analytical, laboratory, and field data
test cases. In particular, the analytical solution of a solitary wave
runup on a simple beach, and its laboratory counterpart, two more
laboratory tests: the runup of a solitary wave on a conically shaped
island and the runup onto a complex 3D beach (Monai Valley) and,
finally, a field data benchmark based on data from the 1993 Hok-
kaido Nansei-Oki tsunami.
Key words: Numerical modeling, model benchmarking,
tsunami, HySEA model, inundation.
1. Introduction
According to the 2006 Tsunami Warning and
Education Act, all inundation models used in
National Tsunami Hazard Mitigation Program
(NTHMP) projects must meet benchmarking stan-
dards and be approved by the NTHMP Mapping and
Modeling Subcommittee (MMS). To this end, a
workshop was held in 2011 by the MMS, and
participating models whose results were approved for
tsunami inundation modeling were documented in the
‘Proceedings and results of the 2011 NTHMP Model
Benchmarking Workshop’’ (NTHMP 2012). Since
then, other models have been subjected to the
benchmark problems used in the workshop, and their
approval and use subsequently requested for NTHMP
projects. For those currently wishing to benchmark
their tsunami inundation models, a first step consists
of completing benchmark problems 1, 4, 6, 7, and 9
in NTHMP (2012). This is the aim of the present
benchmarking study for the case of the Tsunami-
HySEA model. Another preliminary requirement for
achieving MMS approval for tsunami inundation
models is that all models being used by US federal,
state, territory, and commonwealth governments
should be provided to the public as open source. A
freely accessible open source version of Tsunami-
HySEA can be downloaded from the website https://
edanya.uma.es/hysea.
Besides NTHMP (2012) and references therein,
for NTHMP-benchmarked tsunami models, other
authors have performed similar benchmarking efforts
as the one presented here with their particular models,
as is the case of Nicolsky et al. (2011), Apotsos et al.
(2011) or Tolkova (2014). In addition, a model
intercomparison of eight NTHMP models for
benchmarks 4 (laboratory simple beach) and 6 (con-
ical island) can be found in the study by Horrillo et al.
(2015).
2. The Tsunami-HySEA Model
HySEA (Hyperbolic Systems and Efficient Algo-
rithms) software consists of a family of geophysical
1
Departamento de A.M., E. e I.O. y Matema
´tica Aplicada,
Facultad de Ciencias, University of Ma
´laga, Campus de Teatinos,
s/n, 29080 Ma
´laga, Spain. E-mail: jmacias@uma.es
2
Laboratorio de Me
´todos Nume
´ricos, SCAI, University of
Ma
´laga, Campus de Teatinos, s/n, 29080 Ma
´laga, Spain.
3
Departamento de Matema
´tica Aplicada, E.T.S. Telecomu-
nicacio
´n, University of Ma
´laga, Campus de Teatinos, s/n, 29080
Ma
´laga, Spain.
Pure Appl. Geophys. 174 (2017), 3147–3183
2017 The Author(s)
This article is an open access publication
DOI 10.1007/s00024-017-1583-1 Pure and Applied Geophysics
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
codes based on either single-layer, two-layer strati-
fied systems or multilayer shallow-water models.
HySEA codes have been developed by EDANYA
Group (https://edanya.uma.es) from the Universidad
de Ma
´laga (UMA) for more than a decade and they
are in continuous evolution and upgrading. Tsunami-
HySEA is the numerical model specifically designed
for tsunami simulations. It combines robustness,
reliability, and good accuracy in a model based on a
GPU faster than real-time (FTRT) implementation. It
has been thoroughly tested, and in particular has
passed not only all tests by Synolakis et al. (2008),
but also other laboratory tests and proposed bench-
mark problems. Some of them can be found in the
studies by Castro et al. (2005,2006,2012), Gallardo
et al. (2007), de la Asuncio
´n et al. (2013), and
NTHMP (2016).
2.1. Model Equations
Tsunami-HySEA solves the well-known 2D non-
linear one-layer shallow-water system in both spher-
ical and Cartesian coordinates. For the sake of brevity
and simplicity, only the latter system is written:
oh
otþohuðÞ
oxþohvðÞ
oy¼0;
ohuðÞ
otþo
oxhu2þ1
2gh2

þohuvðÞ
oy¼gh oH
oxþSx;
oðhvÞ
otþo
oyhv2þ1
2gh2

þohuvðÞ
ox¼gh oH
oyþSy:
In the previous set of equations, hx;tðÞdenotes
the thickness of the water layer at point x2DR2
at time t, with Dbeing the horizontal projection of
the 3D domain where tsunami takes place. HxðÞis
the depth of the bottom at point xmeasured from a
fixed level of reference. ux;tðÞand vx;tðÞare the
height-averaged velocity in the x- and y-directions,
respectively, and gdenotes gravity. Let us also
define the function gx;tðÞ¼hx;tðÞHðxÞthat
corresponds to the free surface of the fluid.
The terms Sxand Syparameterize the friction
effects and two different laws are considered:
1. The Manning law:
Sx¼ghM2
nuu;vÞk
h4=3;
Sy¼ghM2
nvu;vÞk
h4=3;
where Mn[0 is the manning coefficient.
2. A quadratic law:
Sx¼cfuu;vÞk;Sy¼cfvu;vÞk;
where cf[0 is the friction coefficient. In all the
numerical tests presented in this study the Manning
law is used.
Finally, to perform the BP4 (runup in a simple
beach-experimental) and BP6 (conical island), a
version of the code including dispersion was
used. Dispersive model equations are written as
follows:
Figure 1
Non-scaled sketch of a canonical 1D simple beach with a solitary wave (X
0
=dcot b)
3148 J. Macı
´as et al. Pure Appl. Geophys.
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oh
otþohuðÞ
oxþohvðÞ
oy¼0;
ohuðÞ
otþo
oxhu2þ1
2gh2þ1
2hp

þohuvðÞ
oy¼ðgh þpÞoH
oxþSx;
oðhvÞ
otþo
oyhv2þ1
2gh2þ1
2hp

þohuvðÞ
ox¼ðgh þpÞoH
oyþSy;
ohwðÞ
ot¼p;
hoðhuÞ
oxhu o2ghðÞ
oxþhohvðÞ
oyhv o2ghðÞ
oyþ2hw ¼0:
The dispersive system implemented can be inter-
preted as a generalized Yamazaki model (Yamazaki
et al. 2009) where the term oh
otwis not neglected in the
equation for the vertical velocity. The free divergence
equation has been multiplied by h2to write it with the
conserved variables hu and hv. In addition, due to the
rewriting of the last equation, no special treatment is
required in the presence of wet–dry fronts. The
breaking criteria employed is similar to the criteria
presented by Roeber et al. (2010), based on an ‘‘eddy
viscosity’’ approach.
2.2. Numerical Solution Method
Tsunami-HySEA solves the two-dimensional
shallow-water system using a high-order (second
and third order) path-conservative finite-volume
method. Values of h;hu and hv at each grid cell
represent cell averages of the water depth and
momentum components. The numerical scheme is
conservative for both mass and momentum in flat
bathymetries and, in general, is mass preserving for
arbitrary bathymetries. High order is achieved by a
non-linear total variation diminishing (TVD) recon-
struction operator of the unknowns h;hu;hv and
g¼hH. Then, the reconstruction of His recov-
ered using the reconstruction of hand g. Moreover, in
the reconstruction procedure, the positivity of the
water depth is ensured. Tsunami-HySEA implements
several reconstruction operators: MUSCL (Mono-
tonic Upstream-Centered Scheme for Conservation
Laws, see van Leer 1979) that achieves second order,
the hyperbolic Marquina’s reconstruction (see Mar-
quina 1994) that achieves third order, and a TVD
combination of piecewise parabolic and linear 2D
reconstructions that also achieves third order [see
Gallardo et al. (2011)]. The high-order time
discretization is performed using the second- or
third-order TVD Runge–Kutta method described in
Gottlieb and Shu (1998). At each cell interface,
Tsunami-HySEA uses Godunov’s method based on
the approximation of 1D projected Riemann prob-
lems along the normal direction to each edge. In
particular Tsunami-HySEA implements a PVM-type
(polynomial viscosity matrix) method that uses the
fastest and the slowest wave speeds, similar to HLL
(Harten–Lax–van Leer) method (see Castro and
Ferna
´ndez-Nieto 2012). A general overview of the
derivation of the high-order methods is shown by
Castro et al. 2009. For large computational domains
and in the framework of Tsunami Early Warning
Systems, Tsunami-HySEA also implements a two-
step scheme similar to leap-frog for the deep-water
propagation step and a second-order TVD-weighted
averaged flux (WAF) flux-limiter scheme, described
by de la Asuncio
´n et al. 2013, for close to coast
propagation/inundation step. The combination of
both schemes guaranties the mass conservation in
the complete domain and prevents the generation of
spurious high-frequency oscillations near discontinu-
ities generated by leap-frog type schemes. At the
same time, this numerical scheme reduces computa-
tional times compared with other numerical schemes,
while the amplitude of the first tsunami wave is
preserved.
Figure 2
Water level profiles during runup of the non-breaking wave in the
case H/d=0.019 at time t=55 (d/g)
1/2
for three different
numerical resolutions. Comparison with the analytical solution
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Concerning the wet–dry fronts discretization,
Tsunami-HySEA implements the numerical treat-
ment described by Castro et al. (2005) and Gallardo
et al. (2007) that consists of locally replacing the 1D
Riemann solver used during the propagation step, by
another 1D Riemann solver that takes into account
Figure 3
Maximum runup as a function of time for the three resolutions considered. The black dot showing the analytical maximum runup at t=55 s
Figure 4
Water level profiles during runup of the non-breaking wave in the case H/d=0.019 on the 1:19.85 beach (at times t=35 (d/g)
1/2
,t=40 (d/
g)
1/2
,t=45 (d/g)
1/2
, and t=50 (d/g)
1/2
. Normalized root mean square deviation (NRMSD) and maximum wave amplitude error (ERR) are
computed and shown for each time
3150 J. Macı
´as et al. Pure Appl. Geophys.
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the presence of a dry cell. Moreover, the reconstruc-
tion step is also modified to preserve the positivity of
the water depth. The resulting schemes are well
balanced for the water at rest, that is, they exactly
preserve the water at rest solutions, and are second-
or third-order accurate, depending on the reconstruc-
tion operator and the time stepping method. Finally,
the numerical implementation of Tsunami-HySEA
has been performed on GPU clusters (de la Asuncio
´n
et al. 2011,2013, Castro et al. 2011) and nested-grids
configurations are available (Macı
´as et al.
2013,2014,2015,2016). These facts allow to speed
up the computations, being able to perform complex
simulations, in very large domains, much faster than
real time (Macı
´as et al. 2013,2014,2016).
The dispersive model implements a formal second-
order well-balanced hybrid finite-volume/difference
(FV/FD) numerical scheme. The non-hydrostatic sys-
tem can be split into two parts: one corresponding to the
non-linear shallow-water component in conservative
form and the other corresponding to the non-hydro-
static terms. The hyperbolic part of the system is
discretized using a PVM path-conservative finite-
volume method (Castro and Ferna
´ndez-Nieto 2012
and Pare
´s2006), and the dispersive terms are dis-
cretized with compact finite differences. The resulting
ODE system in time is discretized using a TVD Runge–
Kutta method (Gottlieb and Shu 1998).
3. Benchmark Problem Comparisons
This section contains the Tsunami-HySEA results
for each of the five benchmark problems that are
required by the NTHMP Tsunami Inundation Model
Approval Process (July 2015). The specific version of
Tsunami-HySEA code benchmarked in the present
study is the second order with MUSCL reconstruction
and its second-order dispersive counterpart when
dispersion is required. Detailed descriptions of all
benchmarks, as well as topography data when
required and laboratory or field data for comparison
when applicable, can be found in the repository of
benchmark problems https://gitub.com/rjleveque/
nthmp-benchmark-problems for NTHMP, or in the
NCTR repository http://nctr.pmel.noaa.gov/
Figure 5
Water level profiles during runup of the non-breaking wave in the case H/d=0.019 on the 1:19.85 beach at times t=55 (d/g)
1/2
,t=60 (d/
g)
1/2
, and t=65 (d/g)
1/2
.NRMSD normalized root mean square deviation, MAX maximum amplitude or runup error
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benchmark/. Results from model participating in
original 2011 workshop can be found at NTHMP
(2012). For the sake of completeness, a brief descrip-
tion of each benchmark problem is provided. For BP#1
and BP#4, dealing with analytical solutions or very
simple laboratory 1D configurations, non-dimensional
variables are used everywhere. For problems dealing
with 2D complex laboratory experiments (BP#6 and
BP#7) scaled dimensional problems are solved.
Finally, BP#9 dealing with field data is solved in real-
world not-scaled dimensional variables.
3.1. Benchmark Problem #1: Simple Wave
on a Simple Beach—analytical—CASE H/
d=0.019
In this section, we compare numerical results
for solitary wave shoaling on a plane beach to an
Figure 6
Water level time series at location x/d=9.95 (upper panel) and at location x/d=0.25 (lower panel). Mesh resolution is 800 points
Table 1
Tsunami-HySEA model surface profile errors with respect to the analytical solution for H =0.019 at times t =35:5:65 (d/g)
1/2
. Comparison
with the mean value for NTHMP models in NTHMP (2012)
Model error for case H=0.019
t=35 t=40 t=45 t=50 t=55 t=60 t=65 Mean
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
Tsunami-HySEA model error
1 1 1 0 1 0 0 3 0 1 0 0 2 1 0.85 0.84
Mean error for NTHMP models
22 22 22 12 00 01 53 22
RMS normalized root mean square deviation, MAX maximum amplitude or runup error
3152 J. Macı
´as et al. Pure Appl. Geophys.
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analytic solution based on the shallow-water equa-
tions. The benchmark data for comparison are
obtained from NTHMP (2012) or Synolakis et al.
(2008). In the present case, the model has been run
in non-linear, non-dispersive, and no friction mode
as requested for comparison and verification
purposes. In this problem, the wave of height
His initially centered at distance Lfrom the beach
toe and the shape for the bathymetry consists of an
area of constant depth d, connected to a plane
sloping beach of angle b=arccot(19.85) as
schematically shown in Fig. 1.
Figure 7
Comparison of numerically calculated free surface profiles at various dimensionless times for the non-breaking case H/d=0.0185 with the
lab data. Non-dispersive Tsunami-HySEA model
Table 2
Tsunami-HySEA model sea level time series errors with respect to the analytical solution for H =0.019 at x =9.95 and x =0.25.
Comparison with the mean value for NTHMP models in NTHMP (2012), taken from Tables 1–7 b in p. 38
Model error for case H=0.019
x=9.95 x=0.25 Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Tsunami-HySEA 1 1 1 0 0.58 0.68
Mean NTHMP (2012)212121
RMS normalized root mean square deviation, MAX maximum amplitude or runup error
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Figure 8
Comparison of numerically calculated free surface profiles at various dimensionless time for the non-breaking case H/d=0.0185 with the lab
data. Dispersive Tsunami-HySEA model
Table 3
Tsunami-HySEA model surface profile errors with respect to the lab experiment for Case A, H =0.0185 at times t =30:10:70 (d/g)
1/2
. The
values for NTHMP models are taken or computed from data in Table 1–8 a in p. 41 in NTHMP (2012)
Model error for CASE H=0.0185
t=30 t=40 t=50 t=60 t= 70 Mean
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
RMS
(%)
MAX
(%)
NDH 10.35 5.83 6.72 2.27 3.52 9.88 3.13 2.69 9.15 8.44 6.57 5.82
NDN 11 6 9 3 6 13 4 1 33 15 10 8
DH 6.69 3.92 5.35 1.19 4.6 5.12 3.24 1.73 8.63 3.59 5.7 2.1
DN 11 3 8 2 4 3 5 4 12 6 8 3.5
AN114835 75316995
RMS normalized root mean square deviation, MAX maximum amplitude or runup error, NDH Tsunami-HySEA non-dispersive, NDN non-
dispersive models in NTHMP (2012) (Alaska, GeoClaw, and MOST), DH Tsunami-HySEA dispersive, DN dispersive models in NTHMP
(2012) (ATFM, BOSZ, FUNWAVE, NEOWAVE, and SELFE), AN mean of all models in NTHMP (2012)
3154 J. Macı
´as et al. Pure Appl. Geophys.
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3.1.1 Problem Setup
Problem setup is defined by the following items (all
the variables in this BP are non-dimensional and the
computations have been performed in non-dimen-
sional variables):
Friction: no friction (as required).
Parameters:d=1, g=1, and H=0.019 (see
Fig. 1for dand H).
Computational domain: the computational domain
in x spanned from x=-10 to x=70.
Boundary conditions: a non-reflective boundary
condition at the right side of the computational
domain is imposed (beach slope is located to the
left).
Initial condition: the prescribed soliton at time t=0
with the proposed correction for the initial velocity.
These initial data were given by:
gx;0ðÞ¼Hsech2ðcðxX1Þ=dÞ;
where X1¼X0þL, with L¼arccoshðffiffiffiffiffi
20
pÞ=cthe
half-length of the solitary wave, and c¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffi
3H=4d
p
the water wave elevation and
ux;0ðÞ¼
ffiffi
g
d
rgðx;0Þ
for the initial velocity (the minus sign meaning
approaching the coast, that in the numerical test is on
the left-hand side).
Grid resolution: the numerical results presented are
for a computational mesh composed of 800 cells,
i.e., Dx=0.1 =d/10. For the convergence analysis
of the maximum runup, two other increased reso-
lutions have been used, Dx=0.05 =d/20 and
Dx=0.025 =d/40 with 1600 and 3200 cells,
respectively.
Figure 9
Comparison of numerically calculated free surface profiles at various dimensionless times for the breaking case H/d=0.3 with the lab data.
Non-dispersive model
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Time stepping: variable time stepping based on a
CFL condition is used.
CFL: CFL number is set to 0.9.
Versions of the code: Tsunami-HySEA third-order
(with Marquina’s reconstruction) and second-order
(with MUSCL reconstruction) models have been
benchmarked using this particular problem. Both
models give nearly identical results.
3.1.2 Tasks to be Performed
To accomplish this benchmark the following four
tasks were suggested:
1. Numerically compute the maximum runup of the
solitary wave.
2. Compare the numerically and analytically com-
puted water level profiles at t=25 (d/g)
1/2
,
t=35 (d/g)
1/2
,t=45 (d/g)
1/2
,t=55 (d/g)
1/2
,
and t=65 (d/g)
1/2
. Note that as we used the
MATLAB scripts and data provided by Juan
Horrillo on behalf of the NTHMP, the numerical
vs analytical comparison is performed at the times
given in the provided data and depicted by the
corresponding MATLAB script that does not
correspond exactly with all the time instants given
in BP1 description. More precisely, they do
correspond to t=35:5:65 (d/g)
1/2
. Therefore,
t=25 (d/g)
1/2
is missing and t=40, 50, and
60 (d/g)
1/2
are shown.
3. Compare the numerically and analytically com-
puted water level dynamics at locations x/
d=0.25 and x/d=9.95 during propagation and
reflection of the wave.
4. Demonstrate scalability of the code.
Figures 2,3,4,5and 6show the plots corre-
sponding to these four tasks.
Figure 10
Comparison of numerically calculated free surface profiles at various dimensionless times for the breaking case H/d=0.3 with the lab data.
Dispersive model
3156 J. Macı
´as et al. Pure Appl. Geophys.
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Figure 11
Maximum runup as a function of time. Upper panel Case A.Lower panel Case C.Red dots mark the maximum runup over time for non-
dispersive model and green dots for the dispersive model
Table 4
Tsunami-HySEA model surface profile errors with respect to the lab experiment for Case C, H =0.30 at times t =15:5:30 (d/g)
1/2
. Non-
dispersive, dispersive model results and the mean of the four models with dispersion in NTHMP (2012) that presented results for this test are
collected in this table. The values for NTHMP models are taken from data in Tables 1–8 b in p. 41 in NTHMP (2012)
Model error for CASE H=0.30
t=15 t=20 t=25 t=30 Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Non-dispersive 22.5 17.33 17.42 52.34 5.17 10.07 2.32 3.09 11.85 20.70
Dispersive 2.25 0.25 3.63 3.84 5.69 11.97 2.28 0.70 3.46 4.18
Mean NTHMP 7 6 9 11 6 10 4 6 6.5 8
RMS normalized root mean square deviation, MAX maximum amplitude or runup error
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3.1.3 Numerical Results
In this section, we present the numerical results
obtained using Tsunami-HySEA for BP1 according
to the tasks to be performed as given in the
benchmark description.
3.1.3.1 Maximum Runup The maximum runup is
reached at t=55 (d/g)
1/2
. In the case of the reference
numerical experiment with Dx=0.1 and 800 cells,
the value for the maximum runup is 0.08724. For the
refined mesh experiments with Dx=0.05 and
Dx=0.025, the computed runups are 0.09102 and
0.9165, respectively. Comparison of the numerical
solutions with the analytical reference is depicted in
Fig. 2showing the convergence of the maximum
runup to the analytical value as mesh size is reduced.
It must be noted that for the analytical solution at
time t=55 (d/g)
1/2
and location x=-1.8 water
surface is located at 0.0909, but this is not the value
of the analytical runup (that must be a value slightly
above 0.92), as can be seen in Fig. 2.
Figure 3depicts the time evolution for the maxi-
mum runup simulated for the three spatial resolutions
considered. The black dot marks the approximate
location of the analytical maximum runup.
3.1.3.2 Water Level at t =35:5:65 (d/g)
1/2
.
(MATLAB Script and Data from J. Horrillo) The
next two figures show the water level profiles during
the runup of the non-breaking wave in the case H/
d=0.019 on the 1:19.85 beach at times t=35:5:50
(d/g)
1/2
in Fig. 4and times t=55:5:65 (d/g)
1/2
in
Fig. 5. For a quantitative comparison with the ana-
lytical solution, normalized root mean square
deviation (NRMSD) and maximum wave amplitude
error (ERR) are computed and shown for each time.
Table 1presents the values that measure model
surface profile errors with respect to the analytical
solution for H=0.019 at considered times. The error
value for a particular time is rounded towards the
nearest integer. The mean values are computed
exactly, using the exact values for all times. Mean
values for the eight models in NTHMP (2012) report
are presented for comparison (taken from Tables 1–7
a in p. 38).
3.1.3.3 Water Level at Locations x/d =0.25 and x/
d=9.95 Figure 6depicts the comparison of the
water level time series of numerical results at both
locations, x/d=0.25 and x/d=9.95, with the ana-
lytical solution. Table 2collects the values that
measure model sea level time series errors with
respect to the analytical solution for H=0.019 at
locations x=9.95 and x=0.25 . The error value for
each location is rounded towards the nearest integer.
Mean values for Tsunami-HySEA are computed
exactly. Mean values for the eight models in NTHMP
(2012) report are presented for comparison (taken
from Tables 1–7 b in p. 38).
3.1.3.4 Scalability Tsunami-HySEA has the option
of solving dimensionless problems, and this is an
option commonly used. When dimensionless prob-
lems are solved, it makes no sense to perform any test
of scalability as the dimensionless problems to be
solved for the different scaled problems will (if
scaled to unity) always be the same.
3.2. Benchmark Problem #4: Simple Wave
on a Simple Beach—Laboratory
This benchmark is the lab counterpart of BP1
(analytical benchmarking comparison). In this
Figure 12
Scatter plot of non-dimensional maximum runup, R/d, versus non-
dimensional incident wave height, H/d, resulting from a total of
more than 40 experiments conducted by Y. Joseph Zhan. Red dots
indicate the non-dispersive numerical simulations and the green
dots the results for the dispersive model. Numerically they are
slightly different but in the graphic they superimpose
3158 J. Macı
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laboratory test, the 31.73-m-long, 60.96-cm-deep,
and 39.97-cm-wide wave tank located at the Califor-
nia Institute of Technology, Pasadena was used with
water of varying depths. The set of laboratory data
obtained has been extensively used for many code
validations. In this BP4, the datasets for the H/
d=0.0185 non-breaking and H/d=0.30 breaking
solitary waves are used for code validation. The
model has been first run in non-linear, non-dispersive
mode. Then a dispersive version of Tsunami-HySEA
has also been used to assess the influence of
dispersive terms in both, non-breaking and breaking
cases, and in both wave shape evolution and maxi-
mum runup estimation.
Figure 13
Basin geometry and coordinate system. Solid lines represent approximate basin and wavemaker surfaces. Circles along walls and dashed lines
represent wave absorbing material. Red dots represent gage locations for time series comparison. (Figure taken from benchmark description)
Table 5
Laboratory gage positions. See Fig. 13 for graphical location
Gage ID X (m) Y (m) Z (cm) Comment
6 9.36 13.80 31.7 270Transect
9 10.36 13.80 8.2 270Transect
16 12.96 11.22 7.9 180Transect
22 15.56 13.80 8.3 90Transect
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3.2.1 Problem Setup
Problem setup is defined by the following items (all
the variables in this BP are non-dimensional and the
computations have been performed in non-dimen-
sional variables):
Friction: Manning coefficient was set to 0.03 for
the non-dispersive model and slightly adjusted for
the dispersive model (0.036 for the H/d=0.30 and
0.032 for H/d=0.0185).
Parameters:d=1, g=1, and H=0.0185 for the
non-breaking Case And H=0.30 for the breaking case.
Computational domain: the computational domain
in x spanned from x=-10 to x=70.
Boundary conditions: a non-reflective boundary
condition at the right side of the computational
domain is imposed.
Initial condition: the prescribed soliton at time
t=0 with the proposed initial velocity. These are
the same conditions as for previous benchmark
problem.
Grid resolution: the numerical results presented are
for a computational mesh composed of 1600 cells,
i.e., Dx=0.05 =d/20.
Time stepping: variable time stepping based on a
CFL condition.
CFL: CFL number is set to 0.9
Versions of the code: Tsunami-HySEA third-
order (with Marquina’s reconstruction) and sec-
ond-order (with MUSCL reconstruction) non-
dispersive models and second-order (with
MUSCL reconstruction) dispersive model have
been benchmarked using this particular problem.
Both non-dispersive models give nearly identical
results. In this case, dispersion plays an impor-
tant role.
3.2.2 Tasks to be Performed
To accomplish this BP, the four following tasks had
to be performed:
Figure 14
Snapshots at several times showing the wavefront splitting in front of the island for Case B (upper panel) at times t=31, 31.5, and 32 s; and
for Case C (lower panel) at times t=29.5, 30.5, and 31 s. Water elevation in meters
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1. Compare numerically calculated surface profiles
at t/T=30:10:70 for the non-breaking case H/
d=0.0185 with the lab data (Case A).
2. Compare numerically calculated surface profiles
at t/T=15:5:30 for the breaking case H/d=0.3
with the lab data (Case C).
3. Numerically compute maximum runup (Case A
and C).
4. Numerically compute maximum runup R/dvs. H/
d.
3.2.3 Numerical Results
In this section, we present the numerical results
obtained using Tsunami-HySEA for BP4 according
to the tasks to be performed as given in the
benchmark description.
3.2.3.1 Water Level at Times t =30, 40, 50, 60, and
70 (d/g)
1/2
for Case A (H/d =0.0185) Figure 7
shows the numerical results for Task 1 comparing the
computed and measured surface profiles for the low-
amplitude case (A) using the non-dispersive version
of Tsunami-HySEA. Figure 8presents the same
comparison but for the dispersive version of the code.
Table 3gathers the values for the normalized root
mean square deviation (NRMSD) and the maximum
amplitude or runup error (MAX) for this case for both
non-dispersive and dispersive models and compares
them with the mean of the eight models in NTHMP
(2012) performing this benchmark problem. For
comparison purpose, models in NTHMP (2012) have
also been split into dispersive (five of them) and non-
dispersive (three), and the mean values for the errors
are presented in Table 3. Values for NTHMP models
are extracted or computed from data in Tables 1–8 a
in p. 41.
3.2.3.2 Water Level at Times t =10, 15, 20, 25, and
30 (d/g)
1/2
for Case C (H/d =0.3) Figure 9shows
the numerical results for Task 2, comparing the
computed and measured surface profiles for the high-
amplitude case (C) using the non-dispersive version
of Tsunami-HySEA. Figure 10 presents the same
comparison but for the dispersive version of the code.
Table 4gathers the values for the normalized root
Figure 15
Snapshots at several times for the numerical simulation showing the wavefronts collide behind the island. Upper panel for Case B (times
shown t=34, 35 and 35.5 s) and lower panel for Case C (times shown t=32, 33 and 34 s). Water surface elevation in meters
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mean square deviation (NRMSD) and the maximum
amplitude or runup error (MAX) for this case for both
non-dispersive and dispersive models and compares
them with the mean of the four non-dispersive models
in NTHMP (2012) that presented their results for this
test (ATFM, BOSZ, FUNWAVE, and NEOWAVE).
The models in NTHMP (2102) not including disper-
sive terms did not present results for this test (data
extracted from Tables 1–8 b in p. 41).
3.2.3.3 Maximum runup (Case A and C) Figure 11
shows the maximum runup as a function of time for
Case A (upper panel) and Case C (lower panel).
Numerical results for models without and with dis-
persion are presented superimposed in each figure for
comparison. The maximum simulated runup is
marked in the time series. In case (A) the maximum
runup of 0.08066 is reached at time t=56–56.5 s for
the non-dispersive model and at time t=56.5 s for a
height of 0.0802 for the dispersive model. In case
(C) a maximum runup height of 0.5117 is reached at
time t=42–42.5 s for the non-dispersive model and
of 0.512 at t=43.5 s for the dispersive model. These
values are marked with red and green dots (respec-
tively) in Fig. 11.
3.2.3.4 Maximum Runup R/d vs. H/d Figure 12
shows the maximum runup, R/d, as a function of H/
dfor the numerical simulations performed without
dispersion (red dots) and including dispersion (green
dots). For the two numerical experiments, with H/
d=0.30 and H/d=0.0185, the computed values for
the maximum runup computed without and with dis-
persion cannot be distinguished in the graphics as the
values only differ slightly. In the same figure a scatter
plot of more than 40 lab experiments conducted by Y.
Joseph Zhan are depicted (Synolakis 1987).
It can be observed that both non-dispersive and
dispersive models perform well in the case of the
non-breaking wave. Nevertheless, this same behavior
does not occur for the breaking wave case. It can be
seen, from Fig. 9, that the non-dispersive model is
Figure 16
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case A
(H=0.045). Tsunami-HySEA non-dispersive model
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not able to capture the time evolution of the wave in
this particular case, tending to produce a shock wave
that travels faster than the actual dispersive wave.
Nevertheless, we observe that when the propagation
phase ends and the inundation step takes place, the
non-dispersive model closely reproduces the
observed new wave. Finally, regardless of whether
we are simulating the breaking or non-breaking wave,
if we simply look at the runup time evolution we
observed that both non-dispersive and dispersive
models produce quite close simulated time series
(Fig. 11).
3.3. Benchmark Problem #6: Solitary Wave
on a Conical Island—Laboratory
The goal of this benchmark problem is to compare
computed model results with laboratory
measurements obtained during a physical modeling
experiment conducted at the Coastal and Hydraulic
Laboratory, Engineering Research and Development
Center of the US: Army Corps of Engineers (Briggs
et al. 1995). The laboratory physical model was
constructed as an idealized representation of Babi
Island, in the Flores Sea, Indonesia, to compare with
Babi Island runup measured shortly after the 12
December 1992 Flores Island tsunami (see Fig. 13 for
a schematic picture).
Three cases (A, B, and C) were performed
corresponding to three wavemaker paddle
trajectories.
To accomplish this benchmark, it is suggested that
for
CASE B: water depth, d=32.0 cm, target
H=0.10, measured H=0.096 (this case was
formerly optional).
Figure 17
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case A
(H=0.096). Tsunami-HySEA dispersive model
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CASE C: water depth, d=32.0 cm, target
H=0.20, measured H=0.181.
To perform the tasks described below in
Sect. 3.3.2.
The Case A, that was formerly mandatory, now is
not included:
CASE A: water depth, d=32.0 cm, target
H=0.05, measured H=0.045
In any case, we will include the three cases for all
the tasks but for the splitting–colliding item.
3.3.1 Problem Setup
The main features describing the numerical setup of
the problem are:
Friction: Manning coefficient is set to 0.015 for the
non-dispersive model and to 0.02 for the dispersive
model.
Computational domain:[-5, 23] 9[0, 28] in
meters.
Boundary conditions: open boundary conditions.
Initial condition: the prescribed soliton centered at
x=0 with the proposed correction for the initial
velocity (same expression as in BP1 and BP4, but
extended to two dimensions, with wave elevation
constant and zero velocity in the y-direction).
Grid resolution: for the non-dispersive model a
spatial grid resolution of 5 cm is used for Case A
and a 2-cm resolution grid for Cases B and C.
Dispersive model uses a 2-cm resolution for the
three cases.
Time stepping: variable time stepping based on a
CFL condition.
CFL: 0.9
Versions of the code: Tsunami-HySEA second
order with MUSCL reconstruction (non-dispersive)
and second-order dispersive with MUSCL recon-
struction codes have been used.
Figure 18
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case B
(H=0.096). Tsunami-HySEA non-dispersive model
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3.3.2 Tasks to be Performed
Model simulations must be conducted to address the
following objectives (for cases B and C):
1. Demonstrate that two wavefronts split in front of
the island and collide behind it;
2. Compare computed water level with laboratory
data at gauges 9, 16, and 22 (see Fig. 13 for
graphical location and Table 5for actual
coordinates);
3. Compare computed island runup with laboratory
gage data.
3.3.3 Numerical Results
Note that as we used the MATLAB scripts and data
provided by J. Horrillo (Texas A&M University), we
decided to perform numerical experiments for all the
three cases A, B, and C, and also to present water
level at gauge 6, although not included as mandatory
requirements. For this benchmark, we have used
Tsunami-HySEA non-dispersive and dispersive codes
and have compared shape wave evolution and final
maximum runup.
3.3.3.1 Wave Splitting and Colliding Figure 14
presents snapshots at different times for Case B (in
upper panel) and Case C (in lower panel) showing
how two wavefronts split in front of the island (Task
1). For Case B times t=31, 31.5, and 32 are shown
and for Case C times t=29.5, 30.5, and 31 are
presented.
Figure 15 presents snapshots at different times for
Case B (upper panel) and Case C (lower panel)
showing how two wavefronts, after splitting, collide
Figure 19
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case B
(H=0.096). Tsunami-HySEA dispersive model
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behind the island (Task 1). For Case B times t=34,
35, and 35.5 s are shown and for Case C times
t=32, 33, and 34 s are presented.
3.3.3.2 Water Level at Gauges In this section, we
present the comparison of the computed and
measured water level at gauges 6, 9, 16, and 22 for
the cases (A), (B), and (C), respectively. For each
case, first the results for the non-dispersive model
are presented, then the results for the dispersive
code. Figures 16 and 17 show the comparison for
case (A) of the computed with Tsunami-HySEA
non-dispersive and dispersive model and measured
data, respectively. Figures 18 and 19 present the
comparison for case (B) and Figs. 20 and 21 for
case (C). Tables 6,7,and8gather the sea level
time series Tsunami-HySEA non-dispersive and
dispersive models’ error with respect to laboratory
experiment data for CaseA,B,andC,respec-
tively. Comparison with the mean value obtained
for the eight models performing this benchmark in
NTHMP (2012) split into non-dispersive and dis-
persive models is also included.
It can be observed that as we increase the value of
Hmoving from Case A to B and Case C, the
mismatch between the simulated wave and the
measured one increases for the non-dispersive model.
The differences mostly increase in the leading wave.
On the other hand, the dispersive model performs
equally well in all the three cases.
3.3.3.3 Runup Around the Island Figure 22 pre-
sents the runup numerically computed around the
island with the non-dispersive model, compared
against the experimental data for the three cases.
Figure 23 shows the same comparison but for the
dispersive model. The values for the NRMSD and
maximum error runup are computed and shown in the
figures. Table 9gathers the values for these errors for
Tsunami-HySEA (dispersive and non-dispersive) and
Figure 20
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case C
(H=0.181). Tsunami-HySEA non-dispersive model
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compared them with the mean of the model in
NTHMP (2012) split in non-dispersive and dispersive
models too.
In this benchmark, the observed behavior of the
simulated maximum runup for non-dispersive and
dispersive models through the three cases considered
is not so easily explained. Now for cases A and B, in
the extremes, both models perform similarly well. In
Case B, the non-dispersive model performs clearly
worse, while the dispersive model performs equally
well.
3.4. Benchmark Problem #7: The Tsunami Runup
onto a Complex Three-Dimensional Model
of the Monai Valley Beach—Laboratory
A laboratory experiment using a large-scale tank
at the central Research Institute for Electric Power
Industry in Abiko, Japan was focused on modeling
the runup of a long wave on a complex beach near the
village of Monai (Liu et al. 2008). The beach in the
laboratory wave tank was a 1:400-scale model of the
bathymetry and topography around a very narrow
gully, where extreme runup was measured. More
information regarding this benchmark can be found in
the study by Synolakis et al. (2008). Figure 24 shows
the computational domain and the bathymetry.
3.4.1 Problem Setup
The main items describing the numerical setup of this
problem are:
Friction: Manning coefficient is set to 0.03
Computational domain: [0, 5.488] 9[0, 3.402]
(units in meters).
Boundary conditions: the given initial wave
(Fig. 25) was used to specify the boundary condi-
tion at the left boundary up to time t=22.5 s;
Figure 21
Comparison between the computed and measured water level at gauges 6, 9, 16, and 22 for an incident solitary wave in the Case C
(H=0.181). Tsunami-HySEA dispersive model
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after time t=22.5 s, non-reflective boundary
conditions. Solid wall boundary conditions were
used at the top and bottom boundaries.
Initial condition: water at rest.
Grid resolution: a 393 9244-size mesh was used,
with the same resolution (0.014 m) as the bathy-
metry. Table 10 collects grid information.
Time stepping: variable time stepping based on a
CFL condition.
CFL: 0.9
Versions of the code: Tsunami-HySEA second
order with MUSCL reconstruction and WAF
models used for this benchmark. Second-order
model results are presented.
3.4.2 Tasks to be Performed
To accomplish this benchmark, the following tasks
had to be performed:
1. Model the propagation of the incident and reflec-
tive wave according to the benchmark-specified
boundary condition.
2. Compare the numerical and laboratory-measured
water level dynamics at gauges 5, 7, and 9 (in
Fig. 24).
3. Show snapshots of the numerically computed
water level at time synchronous with those of
the video frames; it is recommended that each
Table 6
Sea level time series Tsunami-HySEA model error with respect to laboratory experiment data for Case A (H =0.045). Comparison with the
mean value obtained for the eight models performing this benchmark in NTHMP (2012) separated among non-dispersive (Alaska, Geoclaw,
and MOST) and dispersive models (ATFM, BOSZ, FUNWAVE, NEOWAVE, and SELFE), for a more precise comparison. The values for
NTHMP models are taken from data in Tables 1–9 a in p. 46
Sea level model error for CASE A (H=0.045)
Gauge # 6 Gauge # 9 Gauge # 16 Gauge # 22 Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Tsunami-HySEA 10 3 9 5 9 5 8 10 9 5.6
Mean NTHMP-ND 6 9 7 14 10 10 8 25 8 15
Tsunami-HySEA-D 9 2 9 3 8 2 8 9 8.3 3.9
Mean NTHMP-D 8 7 8 9 9 12 8 12 8 10
Mean All NTHMP 7 8 8 10 9 12 8 18 8 12
RMS normalized root mean square deviation error, MAX maximum runup relative error
Table 7
Sea level time series Tsunami-HySEA model error with respect to laboratory experiment data for Case B (H =0.096). Comparison with the
mean value obtained for the eight models performing this benchmark in NTHMP (2012) separated among non-dispersive (Alaska, Geoclaw,
and MOST) and dispersive models (ATFM, BOSZ, FUNWAVE, NEOWAVE, and SELFE), for a more precise comparison. The values for
NTHMP models are taken from data in Tables 1–9 b in p. 46
Sea level model error for CASE B (H=0.096)
Gauge # 6 Gauge # 9 Gauge # 16 Gauge # 22 Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Tsunami-HySEA 9 1 8 4 10 1 9 10 9 4
Mean NTHMP-ND 8 6 9 7 7 7 9 40 8 15
Tsunami-HySEA-D 8 3 7 5 9 1 6 0 7.6 2.4
Mean NTHMP-D 7 6 8 10 6 7 10 20 8 11
Mean All NTHMP 8 6 8 9 7 7 9 27 8 12
RMS normalized root mean square deviation error, MAX maximum runup relative error
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Table 8
Sea level time series Tsunami-HySEA model error with respect to laboratory experiment data for Case C (H =0.181). Comparison with the
mean value obtained for the eight models performing this benchmark in NTHMP (2012) separated among non-dispersive (Alaska, Geoclaw,
and MOST) and dispersive models (ATFM, BOSZ, FUNWAVE, NEOWAVE, and SELFE), for a more precise comparison. The values for
NTHMP models are taken from data in Tables 1–9 c in p. 46
Sea level model error for CASE C (H=0.181)
Gauge # 6 Gauge # 9 Gauge # 16 Gauge # 22 Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Tsunami-HySEA 8 7 11 2 10 12 7 10 9 8
Mean NTHMP-ND 10 6 11 9 9 3 8 18 9 9
Tsunami-HySEA-D 7 0 10 7 8 6 6 2 7.9 3.9
Mean NTHMP-D 7 3 11 16 7 4 9 12 8 9
Mean All NTHMP 8 5 11 13 8 3 8 15 9 9
RMS normalized root mean square deviation error, MAX maximum runup relative error
Figure 22
Comparison between the computed and measured runup around the island for the three cases. Non-dispersive results
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modeler finds times of the snapshots that best fit
the data.
4. Compute maximum runup in the narrow
valley.
3.4.3 Numerical Result
In this section, we present the numerical results for
BP7 as simulated by Tsunami-HySEA according to
Figure 23
Comparison between the computed and measured runup around the island for the three cases. Tsunami-HySEA dispersive model
Table 9
Runup Tsunami-HySEA model error with respect to laboratory experiment data for all Cases A, B, and C. Comparison with the mean value
obtained for the eight models performing this benchmark in NTHMP (2012) separated among non-dispersive (Alaska, Geoclaw, and MOST)
and dispersive models (ATFM, BOSZ, FUNWAVE, NEOWAVE, and SELFE), for a more precise comparison. The values for NTHMP models
are taken from data in Tables 1–10 in p. 47
Runup model error
CASE A (H=0.045) CASE B (H=0.096) CASE C (H=0.181) Mean
RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%) RMS (%) MAX (%)
Tsunami-HySEA 7 0 19 1 5 0 10 0
Mean NTHMP-ND 18 12 21 2 12 5 17 7
Tsunami-HySEA-D 8 0 4 4 6 5 6 3
Mean NTHMP-D 17 4 16 7 10 5 15 5
Mean All NTHMP 18 7 18 5 11 5 16 5
RMS normalized root mean square deviation error, MAX maximum runup relative error
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the tasks to be performed as given in the benchmark
description.
3.4.3.1 Gauge Comparison Figure 26 shows a
comparison of Tsunami-HySEA results with the
laboratory values for the three requested gauges from
t=0tot=30 s. Superimposed is the normalized
root mean square deviation (NRMSD). A mean value
of 7.66% for the NRMSD is obtained for all the three
gauges for the time series simulating the first 30 s.
3.4.3.2 Frame Comparisons In the laboratory
experiment, the evolution of the wave was recorded.
Five frames (Frames 10, 25, 40, 55, and 70) extracted
Figure 24
Computational domain with bathymetry and gauge locations of the scaled model (units in meters)
0 5 10 15 20 25
−0.02
−0.015
−0.01
−0.005
0
0.005
0.01
0.015
0.02
Time (s)
Height (m)
Figure 25
Prescribed input wave for the left boundary condition, defined from t=0tot=22.5 s
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from the video record of the lab experiment with 0.5-
s interval are shown in the left column of Fig. 27.
These frames focus on the narrow gully where the
highest runup is observed. On the right-hand side of
Fig. 27, snapshots of the numerically computed water
level at times t=15, 15.5, 16, 16.5, and 17 in sec-
onds are presented for comparison. A good
agreement of the numerical solution to observations
in time and space is revealed, and it can be observed
how the numerical model is able to capture the rapid
runup/rundown sequence in this particular key
location.
3.4.3.3 Runup in the Valley A maximum simulated
runup height of 0.0891 (compared with the 0.08958
experimentally measured) is reached at time
t=16.3 s at point (5.1559, 1.8896). Figure 28 shows
the frame corresponding to time t=16.3 s, where
the computed maximum runup location is marked
with a red dot.
3.5. Benchmark Problem #9: Okushiri Island
Tsunami—Field
The goal of this benchmark problem is to compare
computed model results with field measurements
gathered after the 12 July 1993 Hokkaido Nansei-Oki
tsunami (also commonly referred to as the Okushiri
tsunami).
3.5.1 Problem setup
The main items describing the setup of the numerical
problem are:
Table 10
Mesh information showing grid resolution, number of cells and
computing time needed for a 200-s simulation
Grid resolution Dx=Dy(m) # of volumes Comput. time [s-
(min)]
393 9244 0.014 95,892 91.54618 (1.52)
Figure 26
Comparison experimental and simulated water level at gauges 5, 7, and 9 from t=0tot=30 s
Figure 27
Comparison of snapshots of the laboratory experiment with the
numerical simulation. aFrame 10—time 15 s, bframe 25—time
15.5 s, cframe 40—time 16 s, dframe 55—time 16.5 s, eframe
70—time 17 s
c
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Figure 28
Maximum simulated runup, reached at time t=16.3 s, at point (5.15592, 1.88961), reaching a maximum height of 0.0891 (versus the 0.08958
experimentally measured)
Figure 29
Computational domain considered (level 0) showing the initial condition for Benchmark problem #9. Nested meshes level 1 and level 2 (the
latter composed of two submeshes) are also depicted
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Friction: Manning coefficient 0.03.
Boundary conditions: non-reflective boundary con-
ditions at open sea, at coastal areas inundation is
computed.
Computational domain: a nested mesh technique is
used with four levels (i.e., the global mesh with
three levels of refinement, see Figs. 29 and 30).
Global mesh coverage in lon/lat [138.504,
140.552] 9[41.5017, 43.2984].
Number of cells: 1152 91011 =1,164,672.
Resolution: 6.4 arc-sec (&192 m).
Level 1. Spatial coverage [139.39, 139.664] 9
[41.9963, 42.2702].
Refinement ratio: 4.
Number of cells: 616 9616 =379,456.
Resolution: 1.6 arc-sec (&40 m).
Level 2. Refinement ratio: 4. Resolution: 0.4 arc-
sec (&12 m).
Submesh 1: large area around Monai.
Spatial coverage [139.434, 139,499] 9
[42.0315, 42.0724].
Number of cells: 584 9368 =214,912.
Submesh 2: Aonae cape and Hamatsumae
region.
Spatial coverage [139.411, 139.433] 9
[42.0782, 42.1455].
Number of cells: 196 9604 =118,384.
Level 3 (Monai region). Spatial coverage
[139.414, 139.426] 9[42.0947, 42.1033].
Refinement ratio: 16.
Number of cells: 1744 91248 =2,216,448.
Resolution: 0.025 arc-sec (&0.75 m).
Initial condition: generated by DCRC (Disaster
Control Research Center), Japan. Hipocenter depth
Figure 30
Level 1 nested mesh computational domain containing the two level 2 submeshes, the region to the South including Aonae and Hamatsumae
areas and the coastal region to the West containing Monai area, refined with one level 3 nested mesh around Monai Valley
Vol. 174, (2017) Performance Benchmarking of Tsunami-HySEA Model 3175
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Figure 31
Inundation map of the Aonae Peninsula. This is for t\12.59 min. The color map shows the maximum fluid depth over entire computation.
4-m contours of bathymetry and topography are shown
Figure 32
Zoom on the Aonae Peninsula showing the arrival of the first wave coming from the west at times t=4.75 min and t=5 min. We observe
that this first wave impacts the west coast of the Aonae Peninsula at time close to 5 min after the tsunami generation
3176 J. Macı
´as et al. Pure Appl. Geophys.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
37 km at 139.32E and 42.76N, M
w
7.8 (Taka-
hashi 1996) (Fig. 29, source model DCRC 17a).
Topobatymetric data: Kansai University.
CFL: 0.9.
Version of the code: Tsunami-HySEA WAF.
3.5.2 Tasks to be Performed
To evaluate performance requirements for this
benchmark, the following tasks had to be performed:
1. Compute runup around Aonae.
2. Compute arrival of the first wave to Aonae.
Figure 33
Zoom on the Aonae peninsula showing the first wave arriving from the west at time t=5.25 min and the second wave coming from the east
at time t=9.75 min
Figure 34
Computed and observed water levels at two tide stations located along the west coast of Hokkaido Island, Iwanai in upper panel and Esashi in
lower panel. Observations from Yeh et al. (1996)
Vol. 174, (2017) Performance Benchmarking of Tsunami-HySEA Model 3177
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
3. Show two waves at Aonae approximately 10 min
apart; the first wave came from the west, the
second wave came from the east.
4. Compute water level at Iwanai and Esashi tide
gauges.
5. Maximum modeled runup distribution around
Okushiri Island.
6. Modeled runup height at Hamatsumae.
7. Modeled runup height at a valley north of Monai.
3.5.3 Numerical Results
In this section, the numerical results obtained with
Tsunami-HySEA for BP9 are presented.
3.5.3.1 Runup Around Aonae Figure 31 shows the
inundation level around Aonae peninsula. The
figure includes 4-m contours of bathymetry and
topography. The contours allow to determine that the
maximum runup height is below 12 m in the eastern
part of the peninsula where the tsunami inundation is
mainly produced by the second wave and where the
topography is flatter producing, despite the lower
runup, a further penetration. The opposite situation
occurs in the western part of the peninsula: a higher
runup ranging from 16 to 20 m, within a narrower
strip, mainly flooded by the first wave arriving from
the west. The southern part of the peninsula is inun-
dated with a runup height of 16 meters and a large
inundated area, suffering both impacts of the western
and eastern tsunami wave.
3.5.3.2 First Wave to Aoane Figure 32 shows the
arrival of the first wave, coming from the west, to the
Figure 35
Computed and observed runup in meters at 19 regions along the coast of Okushiri Island after 1993 Okushiri tsunami. Observations from Kato
and Tsuji (1994)
3178 J. Macı
´as et al. Pure Appl. Geophys.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Aonae peninsula at times t=4.75 min and
t=5 min. From this figure, we can conclude the
time of arrival of this first wave to Aoane takes place
at approximately t=5 min. Within 15 s the wave is
close to reaching the western coastline of the penin-
sula and at t=5 min it has already impacted, from
north to south, along all the western seashore.
3.5.3.3 Waves Arriving to Aonae Figure 33 depicts
two snapshots of the arrival of two tsunami waves at
the Aonae peninsula. The first wave arrival, from the
west, is seen at about t=5 min, as is shown in
Fig. 32. The second major wave arrives from the east
at about 9.5 min. Snapshots at time t=5.25 min and
t=9.75 min are presented in Fig. 33.
3.5.3.4 Tide gauges at Iwanai and Esashi Fig-
ure 34 shows the comparison between the computed
and observed water levels at two tide stations located
along the west coast of Hokkaido Island, Iwanai and
Esashi. Besides, the maximum error in the maximum
wave amplitude and the normalized root mean square
deviation (NRMSD) is depicted for both time series.
The errors in the maximum amplitude, although high
(36 and 41%) are analogous to the mean of the
models collected in NTHMP (2012) report (36 and
43%, respectively). No values were given for the
NRMSD there.
3.5.3.5 Maximum Runup Around Okushiri Fig-
ure 35 shows a bar plot that compares model runup at
19 regions around Okushiri Island with measured
data. In the NTHMP-provided script, runup error is
Figure 36
Inundation map of the Hamatsumae neighborhood. For t\14 min. The color map shows the maximum fluid depth along the entire
simulation. 4-m contours of bathymetry and topography are shown
Table 11
Tsunami-HySEA model relative error with respect to field
measurement data for runup around Okushiri Island. Comparison
with average error values for models in NTHMP (2102). #OBS
gives the number of observations used to compute the error bars in
Fig. 37
Region Longitude Latitude #
OBS
HySEA
(%)
Mean
NTHMP
(%)
1 139.4292117 42.18818149 3 25 5
2 139.4111857 42.16276287 2 22 8
3 139.4182612 42.13740439 1 66 27
4 139.4280358 42.09301238 1 2 7
5 139.4262450 42.11655479 1 5 6
6 139.4237147 42.10041415 7 2 6
7 139.4289018 42.07663658 1 30 15
8 139.4278534 42.06546152 2 5 10
9 139.4515399 42.04469655 3
a
00
10 139.4565284 42.05169226 5
a
08
11 139.4720138 42.05808988 4 0 2
12 139.5150461 42.21524909 2 0 10
13 139.5545494 42.22698164 6–8 19 14
14 139.4934307 42.06450128 3 32 74
15 139.5474599 42.18744879 1 6 14
16 139.5258982 42.17101221 2 0 11
17 139.5625242 42.21198369 1 9 15
18 139.5190997 42.11305805 3 0 34
19 139.5210766 42.15137635 2 1 19
Mean 12 15
a
When one observed value has been skipped. NTHMP data taken
from Tables 1–11 b in p. 49
Vol. 174, (2017) Performance Benchmarking of Tsunami-HySEA Model 3179
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
evaluated by a comparison between computed and
measured sets of minimal, maximal, and mean runup
values in unspecified surroundings of prescribed ref-
erence points. We have searched for the set of
observations used for each region to compute the
minimal, maximal, and mean values (these are the
three values required for generating Fig. 35). For
each of these observed values the closer or the two
closer model values were considered for the compu-
tation of the minimum, maximum, and the average in
the given region. When only one measured data were
available in a region, then the three closer model
discretized points were taken (this means a larger
spread in simulated values than in measured data that
can be observed in regions 3, 4,5, 7, 15, and 17). This
procedure was used in all cases, but in the regions
with refined meshes (regions 6, 9, 10, and 11), where
all computed values were used.
In Table 11 the location of the points identifying
these 19 regions are gathered and for each region the
number of observations used to determine minimal,
maximal, and mean values are given in column
#OBS. Finally, this table also presents Tsunami-
HySEA runup error at each location compared with
the mean of models in NTHMP (2012). The main
question that arises when regarding this table is why
there are locations with such a good agreement with
observed data and for other regions the agreement is
so poor. First of all, we are dealing with discrete
observed values taken at locations that we do not
know why or how were chosen. This is a first source
of uncertainty. Second, bathymetry data resolution is
very inhomogeneous: where bathymetry data are
finer, closer model vs observed data comparisons are
obtained. Large errors are associated with low
bathymetry data resolution regions. Finally, numer-
ical resolution also varies, and besides it is finer in
regions with higher resolution bathymetry data and
coarser in regions with low-resolution bathymetry.
Besides, as pointed out in NTHMP (2012), the
Figure 37
Inundation map of the valley north of Monai. 4-m contours of bathymetry and topography are shown
3180 J. Macı
´as et al. Pure Appl. Geophys.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
accuracy of the seismic source being used and the
accuracy in some of the field observations and tide
gauges may also play an important role to explain the
observed discrepancies. A detailed study trying to
clarify these aspects is needed.
3.5.3.6 Runup Height at Hamatsumae Figure 36
shows the maximum inundation on the Hamatsumae
region computed for [0, 14] min. The color map
shows the maximum fluid depth along the entire
simulation. The figure also depicts 4-m contours of
bathymetry and topography. Maximum runups are
between 8 and 16 meters, with increasing values from
west to east.
3.5.3.7 Runup Height at a Valley North of
Monai Figure 37 shows the maximum inundation at
a valley north of Monai, computed for [0, 4.5] min.
The color map shows the maximum fluid depth along
the entire simulation. The 4-m contours of topogra-
phy allow to determine maximum runups that range
between 8 and 12 m to the south, around 16 to the
north and up to the 31.753 m of maximum computed
runup, very close to the observed value, 31.7 m.
4. Conclusions
The Tsunami-HySEA numerical model is vali-
dated and verified using NOAA standards and criteria
for inundation. The numerical solutions are tested
against analytical predictions (BP1, solitary wave on
a simple beach), laboratory measurements (BP4,
solitary wave on a simple beach; BP6, solitary wave
on a conical island; and BP7, runup on Monai Valley
beach), and against field observations (BP9, Okushiri
island tsunami). In the numerical experiments mod-
eling the propagation and runup of a solitary wave on
a canonical beach, numerical results are clearly below
the established errors by the NTHMP in their 2011
report. For BP1, the mean errors measured are below
1% in all cases. In the case of BP4, several conclu-
sions can be extracted. For the non-breaking case
with H=0.0185 the non-dispersive model produces
accurate wave forms with NRMSD errors, in most
cases, very close to the dispersive model results. For
the breaking wave case with H=0.30 it can be
observed that the shape of the (dispersive) wave
cannot be well captured by the non-dispersive model,
producing large NRMSD errors at the times when the
NLSW model tends to produce a shock. Nevertheless,
the agreement is still high for times when non-steep
profiles are present. Despite this (a dispersive model
is absolutely necessary if we want to accurately
reproduce the time evolution of the wave in the
breaking case) we have observed that measured runup
is accurately reproduced by both models in the two
studied cases. On the other hand, the dispersive ver-
sion of Tsunami-HySEA produces very good results
in both the breaking and non-breaking cases. For
BP6, dealing with the impact of a solitary wave on a
conical island, again non-dispersive and dispersive
Tsunami-HySEA models have been used. Wave
splitting and colliding are clearly observed. Numeri-
cal results are very similar for Case A (A/h=0.045)
and Case B (A/h=0.096) for wave shape. Larger
differences are evident in Case C (A/h=0.181),
where dispersive model performs better for wave
shape, but not for the computed runup. It is note-
worthy that the computed maximum runups for Cases
A and C are very close for both models but they
clearly differ for Case B. Tsunami-HySEA model
figures have been compared with figures in NTHMP
(2012), performing in general better than the mean
when comparing by class of model (dispersive and
non-dispersive). BP7, the laboratory experiment
dealing with the tsunami runup onto a complex 3D
model of the Monai Valley beach, was studied in
detail in (Gallardo et al. 2007). A mean value of
7.66% for the NRMSD is obtained for all the three
gauges for the times series simulating the first 30 s.
The snapshots of the simulation agree well with the
experimental frames and, finally, a maximum simu-
lated runup height of 0.0891 is obtained compared
with the 0.08958 experimentally measured. Com-
parison of BP9 with Okushiri island tsunami
observed data is performed using nested meshes with
two level 2 meshes located one in the South of the
island, covering Aoane and Hamatsumae areas and
the second one to the West containing Monai area.
Finally, one level 3 refined mesh is located covering
the Monai area. Computed runup and arrival times
are in good agreement with observations. Water level
time series at Iwanai and Esashi tide gauges show
Vol. 174, (2017) Performance Benchmarking of Tsunami-HySEA Model 3181
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
large NRMSD and large errors in the maximum
amplitude (36 and 41% for ERR) but analogous to the
mean of the models in NTHMP (2012) (36 and 43%
for ERR). For the maximum runup at 19 regions
around Okushiri Island a mean error of 15% is
obtained, the same as the mean of models in NTHMP
(2012), with 10 regions with errors below 10%.
Regions located in areas with refined meshes perform
much better than regions located in coarse mesh
areas.
Acknowledgements
This research has been partially supported by the
Spanish Government Research project SIMURISK
(MTM2015-70490-C2-1-R), the Junta de Andalucı
´a
research project TESELA (P11-RNM7069), and
Universidad de Ma
´laga, Campus de Excelencia
Internacional Andalucı
´a Tech. The GPU and multi-
GPU computations were performed at the Unit of
Numerical Methods (UNM) of the Research Support
Central Services (SCAI) of the University of Malaga.
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://
creativecommons.org/licenses/by/4.0/), which permits unrestricted
use, distribution, and reproduction in any medium, provided you
give appropriate credit to the original author(s) and the source,
provide a link to the Creative Commons license, and indicate if
changes were made.
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... Figure 2 shows the distribution of alert coastal zones for a tsunami that might affect the Spanish coasts. Real-time tsunami propagation synthetics in the TWS of Spain are computed using the Tsunami-HySEA model [46][47][48] using GPU parallel computing with two nodes and two NVidia V100 GPUs. The bathymetric domain and simulated time depends on the earthquake location in the Atlantic ocean or in the Mediterranean sea regarding its distance from the Spanish coasts. ...
... The bathymetric domain and simulated time depends on the earthquake location in the Atlantic ocean or in the Mediterranean sea regarding its distance from the Spanish coasts. Therefore, the number of volumes and time of computation Real-time tsunami propagation synthetics in the TWS of Spain are computed using the Tsunami-HySEA model [46][47][48] using GPU parallel computing with two nodes and two NVidia V100 GPUs. The bathymetric domain and simulated time depends on the earthquake location in the Atlantic ocean or in the Mediterranean sea regarding its distance from the Spanish coasts. ...
... The computations of the 540 simulations have been performed using Tsunami-HySEA code [46][47][48] on GPUs using 68 nodes/272 NVIDIA V100 GPUs from a Marconi100 machine at CINECA supercomputing center ( Table 2). These 540 simulations were done during a live demo that took place on 22 November 2021 [23,24]. ...
Article
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Real-time local tsunami warnings embody uncertainty from unknowns in the source definition within the first minutes after the tsunami generates. In general, Tsunami Warning Systems (TWS) provide a quick estimate for tsunami action from deterministic simulations of a single event. In this study, variability in tsunami source parameters has been included by running 135 tsunami simulations; besides this, four different computational domains in the northeastern Atlantic ocean have been considered, resulting in 540 simulations associated with a single event. This was done for tsunamis generated by earthquakes in the Gulf of Cadiz with impact in the western Iberian peninsula and the Canary Islands. A first answer is provided after one minute, and 7 min are required to perform all the simulations in the four computational domains. The fast computation allows alert levels all along the coast to be incorporated into the Spanish National Tsunami Early Warning System. The main findings are that the use of a set of scenarios that account for the uncertainty in source parameters can produce higher tsunami warnings in certain coastal areas than those obtained from a single deterministic reference scenario. Therefore, this work shows that considering uncertainties in tsunami source parameters helps to avoid possible tsunami warning level underestimations. Furthermore, this study demonstrates that this is possible to do in real time in an actual TWS with the use of high-performance computing resources.
... Numerical models of this kind should describe the flood zone with a very high spatial resolution and have reliable numerical flooding/drainage schemes, which is associated with relatively high energy consumption in the computational aspect. In addition, often, the time between the occurrence of a tsunami and its approach to the coast is minimal, and then pre-created databases of possible scenarios of tsunami sources and numerical modelling (Macías et al., 2017;Rakowsky et al., 2013) come to the rescue. The advantage of such models compared to operational ones is a more accurate and detailed description of 30 the processes occurring in the flood zone (Baba et al., 2014; Harig et al., 2022). ...
... Another class of equations contains three types of nonlinearity -momentum advection, nonlinearity in the continuity equation due to variable water thickness, and nonlinear friction (Androsov et al., 2011;Macías et al., 2017). All these types of 40 nonlinearity play different roles in wave propagation near and on the coast. ...
Preprint
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This investigation addresses the tsunami flooding in Lima and Callao caused by the massive 1746 earthquake (Mw 9.0) along the Peruvian coast. Numerical modelling of the tsunami flooding processes in the nearshore includes strong nonlinear numerical terms. In a comparative analysis of the calculation of the tsunami wave effect, two numerical codes are used, Tsunami-HySEA and TsunAWI, which both solve the shallow water (SW) equations but with different spatial approximations. The comparison primarily evaluates the flow velocity fields in flooded areas. The relative importance of the various parts of the SW equations is determined, focusing on the nonlinear terms. Particular attention is paid to the contribution of momentum advection, bottom friction, and volume conservation. The influence of the nonlinearity on the degree and volume of flooding, flow velocity and small-scale fluctuations is determined. The sensitivity of the solution with respect to the value of the bottom friction parameter is investigated as well.
... For this reason, FV methods such as Godunov [24], and Roe [25] solvers, which were previously used in gas dynamics, have become increasingly popular for the solution of long-wave problems. A new generation of tsunami and flooding models has been developed [26][27][28][29] based on a finite-volume interpretation of the equations, where the in-going and out-going fluxes over a control volume are computed with approximate Riemann solvers (e.g., [30][31][32]). These solvers are designed to preserve the hyperbolicity of the governing equations to allow for the formation of discontinuities in the numerical system. ...
... The last term on the right-hand side of Eq. (27) applies only to the momentum equations and involves the corrected flow depth value h n+1 . This completes the fully explicit time integration where no system of equations with data dependencies has to be solved. ...
Article
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Computation of long-wave run-up has been of high interest in the fields of ocean sciences and geophysics—particularly for tsunami and river flood modeling. An accurate calculation of run-up and inundation requires the numerical model to account for a sequence of critical processes—each of them posing a different challenge to the numerical solution. This study presents the strategic development of a numerical solution technique for shallow water equations with a focus on accuracy and efficiency for long-wave run-up. The present model is based on an explicit second-order finite-volume scheme over a staggered grid that efficiently achieves fundamental properties. The scheme is well-balanced and preserves shock fronts without the need for computationally expensive solvers. The streamlined code serves as a foundation for the implementation of nested grids. Computations of commonly used long-wave benchmark tests showcase that accurate predictions of local extreme run-up can often be achieved with highly refined yet spatially focused nested grids. Strategic grid nesting can lead to stable and accurate solutions of run-up at locations of interest and reduce the computational load to a fraction of what is usually necessary for a comparable solution over a single grid.
... The Tsunami-HYSEA code has passed through several benchmarks such as the US National Tsunami Hazard Mitigation Program (NTHMP), and it has been implemented in many Tsunami Early Warning Centres. It has also contributed to fast numerical modelling based on GPU [15] for exascale simulations, allowing for faster than real-time tsunami forecasting [16]. On the other hand, TsunAWI was originally designed to pre-compute scenarios and store the warning products in a database for fast access in case of a real event (see also [6]). ...
... At each cell interface, Tsunami-HySEA uses Godunov's method based on the approximation of 1D projected Riemann problems along the normal direction to each edge. Tsunami-HySEA also implements a two-step scheme similar to leap-frog for the deep water propagation step, and a second-order TVD-WAF flux-limiter scheme for the close-to-coast propagation-to-inundation step [15,30]. The combination of both schemes guarantees mass conservation in the complete domain and prevents the generation of spurious high-frequency oscillations near the discontinuities generated by the leap-frog type schemes (more details at https://edanya.uma.es/hysea/index.php/models/tsunamihysea, ...
Article
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Tsunami inundation estimates are of crucial importance to hazard and risk assessments. In the context of tsunami forecast, numerical simulations are becoming more feasible with the growth of computational power. Uncertainties regarding source determination within the first minutes after a tsunami generation might be a major concern in the issuing of an appropriate warning on the coast. However, it is also crucial to investigate differences emerging from the chosen algorithms for the tsunami simulations due to a dependency of the outcomes on the suitable model settings. In this study, we compare the tsunami inundation in three cities in central Chile (Coquimbo, Viña del Mar, and Valparaíso) using three different models (TsunAWI, Tsunami-HySEA, COMCOT) while varying the parameters such as bottom friction. TsunAWI operates on triangular meshes with variable resolution, whereas the other two codes use nested grids for the coastal area. As initial conditions of the experiments, three seismic sources (2010 Mw 8.8 Maule, 2015 Mw 8.3 Coquimbo, and 1730 Mw 9.1 Valparaíso) are considered for the experiments. Inundation areas are determined with high-resolution topo-bathymetric datasets based on specific wetting and drying implementations of the numerical models. We compare each model’s results and sensitivities with respect to parameters such as bottom friction and bathymetry representation in the varying mesh geometries. The outcomes show consistent estimates for the nearshore wave amplitude of the leading wave crest based on identical seismic source models within the codes. However, with respect to inundation, we show high sensitivity to Manning values where a non-linear behaviour is difficult to predict. Differences between the relative decrease in inundation areas and the Manning n-range (0.015–0.060) are high (11–65%), with a strong dependency on the characterization of the local topo-bathymery in the Coquimbo and Valparaíso areas. Since simulations carried out with such models are used to generate hazard estimates and warning products in an early tsunami warning context, it is crucial to investigate differences that emerge from the chosen algorithms for the tsunami simulations.
... The list of existing numerical models is long and was recently reviewed in Marras and Mandli (2021) 80 and Horrillo et al. (2015). Some commonly used ones are FUNWAVE (Kennedy et al., 2000;Shi et al., 2012), pCOULWAVE (Lynett et al., 2002;Kim and Lynett, 2011), Delft3D (Roelvink and Van Banning, 1995), GeoCLAW , NHWAVE (Ma et al., 2012), Tsunami-HySEA (Macías et al., 2017;Macías et al., 2020b, a), FVCOM (Chen et al., 2003(Chen et al., , 2014. Our work here relies on wellknown numerical techniques to solve idealized tsunami problems. ...
Preprint
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Tsunami-risk and flood-risk mitigation planning has particular importance for communities like those of the Pacific Northwest, where coastlines are extremely dynamic and a seismically-active subduction zone looms large. The challenge does not stop here for risk managers: mitigation options have multiplied since communities have realized the viability and benefits of nature-based solutions. To identify suitable mitigation options for their community, risk managers need the ability to rapidly evaluate several different options through fast and accessible tsunami models, but may lack high-performance computing infrastructure. The goal of this work is to leverage the newly developed Google's Tensor Processing Unit (TPU), a high-performance hardware accessible via the Google Cloud framework, to enable the rapid evaluation of different tsunami-risk mitigation strategies available to all communities. We establish a starting point through a numerical solver of the nonlinear shallow-water equations that uses a fifth-order Weighted Essentially Non-Oscillatory method with the Lax-Friedrichs flux splitting, and a Total Variation Diminishing third-order Runge-Kutta method for time discretization. We verify numerical solutions through several analytical solutions and benchmarks, reproduce several findings about one particular tsunami-risk mitigation strategy, and model tsunami runup at Crescent City, California whose topography comes from a high-resolution Digital Elevation Model. The direct measurements of the simulations performance, energy usage, and ease of execution show that our code could be a first step towards a community-based, user-friendly virtual laboratory that can be run by a minimally trained user on the cloud thanks to the ease of use of the Google Cloud Platform.
... The list of existing numerical models is long and was recently reviewed in Marras and Mandli [2021] and Horrillo et al. [2015]. Some commonly used ones are FUNWAVE [Kennedy et al., 2000, pCOULWAVE [Lynett et al., 2002, Kim andLynett, 2011], Delft3D [Roelvink and Van Banning, 1995], GeoCLAW , NHWAVE [Ma et al., 2012], Tsunami-HySEA [Macías et al., 2017, Macías et al., 2020b, FVCOM [Chen et al., 2003[Chen et al., , 2014. Our work here relies on well-known numerical techniques to solve idealized tsunami problems. ...
Preprint
Full-text available
Tsunami-risk and flood-risk mitigation planning has particular importance for communities like those of the Pacific Northwest, where coastlines are extremely dynamic and a seismically-active subduction zone looms large. The challenge does not stop here for risk managers: mitigation options have multiplied since communities have realized the viability and benefits of nature-based solutions. To identify suitable mitigation options for their community, risk managers need the ability to rapidly evaluate several different options through fast and accessible tsunami models, but may lack high-performance computing infrastructure. The goal of this work is to leverage the newly developed Google's Tensor Processing Unit (TPU), a high-performance hardware accessible via the Google Cloud framework, to enable the rapid evaluation of different tsunami-risk mitigation strategies available to all communities. We establish a starting point through a numerical solver of the nonlinear shallow-water equations that uses a fifth-order Weighted Essentially Non-Oscillatory method with the Lax-Friedrichs flux splitting, and a Total Variation Diminishing third-order Runge-Kutta method for time discretization. We verify numerical solutions through several analytical solutions and benchmarks, reproduce several findings about one particular tsunami-risk mitigation strategy, and model tsunami runup at Crescent City, California whose topography comes from a high-resolution Digital Elevation Model. The direct measurements of the simulations performance, energy usage, and ease of execution show that our code could be a first step towards a community-based, user-friendly virtual laboratory that can be run by a minimally trained user on the cloud thanks to the ease of use of the Google Cloud Platform.
... The inundating flows were estimated using the numerical NLSWE model Tsunami-HySEA, which has been benchmarked and validated in accordance with U.S. National Tsunami Hazard Mitigation Program (NTHMP) [35,36], as well as for currents [37]. Up to four sets of nested grids, with varying spatial resolutions, were built from the freely available General Bathymetric Chart of the Oceans [38] and nautical charts elaborated by the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA). ...
Article
Full-text available
The role of the Manning roughness coefficient in modifying a tsunami time series of flow depth inundation was studied in Iquique, Chile, using a single synthetic earthquake scenario. A high-resolution digital surface model was used as a reference configuration, and several bare land models using constant roughness were tested with different grid resolutions. As previously reported, increasing the Manning n value beyond the standard values is essential to reproduce mean statistics such as the inundated area extent and maximum flow depth. The arrival time showed to be less sensitive to changes in the Manning n value, at least in terms of the magnitude of the error. However, increasing the Manning n value too much leads to a critical change in the characteristics of the flow, which departs from its bore-like structure to a more gradual and persistent inundation. It was found that it is possible to find a Manning n value that resembles most features of the reference flow using less resolution in the numerical grids. This allows us to speed up inundation tsunami modeling, which could be useful when multiple inundation simulations are required.
... The inundation characteristics at both bays were estimated using the numerical NLSWE model Tsunami-HySEA, which has been benchmarked and validated in accordance with U.S. National Tsunami Hazard Mitigation Program (NTHMP) 10,64 . Four sets of nested grids, with spatial resolutions of 30, 15, 1.875 y 0.234 arcsec, were built from the freely available General Bathymetric Chart of the Oceans 65 , and Nautical Charts elaborated by the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA) (Fig. 1). ...
Article
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Tsunamis are natural phenomena that, although occasional, can have large impacts on coastal environments and settlements, especially in terms of loss of life. An accurate, detailed and timely assessment of the hazard is essential as input for mitigation strategies both in the long term and during emergencies. This goal is compounded by the high computational cost of simulating an adequate number of scenarios to make robust assessments. To reduce this handicap, alternative methods could be used. Here, an enhanced method for estimating tsunami time series using a one-dimensional convolutional neural network model (1D CNN) is considered. While the use of deep learning for this problem is not new, most of existing research has focused on assessing the capability of a network to reproduce inundation metrics extrema. However, for the context of Tsunami Early Warning, it is equally relevant to assess whether the networks can accurately predict whether inundation would occur or not, and its time series if it does. Hence, a set of 6776 scenarios with magnitudes in the range Mw 8.0–9.2 were used to design several 1D CNN models at two bays that have different hydrodynamic behavior, that would use as input inexpensive low-resolution numerical modeling of tsunami propagation to predict inundation time series at pinpoint locations. In addition, different configuration parameters were also analyzed to outline a methodology for model testing and design, that could be applied elsewhere. The results show that the network models are capable of reproducing inundation time series well, either for small or large flow depths, but also when no inundation was forecast, with minimal instances of false alarms or missed alarms. To further assess the performance, the model was tested with two past tsunamis and compared with actual inundation metrics. The results obtained are promising, and the proposed model could become a reliable alternative for the calculation of tsunami intensity measures in a faster than real time manner. This could complement existing early warning system, by means of an approximate and fast procedure that could allow simulating a larger number of scenarios within the always restricting time frame of tsunami emergencies.
... Most recent numerical models of tsunami propagation take frequency dispersion into account. These ones are based either on Boussinesq-type equations [4,5] or on nonlinear shallow water equations coupled with a pressure Poisson equation [6,7]. ...
Article
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One of the features of Boussinesq-type models for dispersive wave propagation is the presence of mixed spatial/temporal derivatives in the partial differential system. This is a critical point in the design of the time marching strategy, as the cost of inverting the algebraic equations arising from the discretization of these mixed terms may result in a nonnegligible overhead. In this paper, we propose novel approaches based on the classical Lax–Wendroff (LW) strategy to achieve single-step high-order schemes in time. To reduce the cost of evaluating the complex correction terms arising in the Lax–Wendroff procedure for Boussinesq equations, we propose several simplified strategies which allow to reduce the computational time at fixed accuracy. To evaluate these qualities, we perform a spectral analysis to assess the dispersion and damping error. We then evaluate the schemes on several benchmarks involving dispersive propagation over flat and nonflat bathymetries, and perform numerical grid convergence studies on two of them. Our results show a potential for a CPU reduction between 35 and 40% to obtain accuracy levels comparable to those of the classical RK3 method.
Article
With Exascale computing already here, supercomputers are systems every time larger, more complex, and heterogeneous. While expert system administrators can install and deploy applications in the systems correctly, this is something that general users can not usually do. The eFlows4HPC project aims to provide methodologies and tools to enable the use and reuse of application workflows. One of the aspects that the project focuses on is simplifying the application deployment in large and complex systems. The approach uses containers, not generic ones, but containers tailored for each target High-Performance Computing (HPC) system. This paper presents the Container Image Creation service developed in the framework of the project and experimentation based on project applications. We compare the performance of the specialized containers against generic containers and against a native installation. The results show that in almost all cases, the specialized containers outperform the generic ones (up to 2× faster), and in all cases, the performance is the same as with the native installation.
Article
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Tsunami-HySEA model is used to simulate the Caribbean LANTEX 2013 scenario (LANTEX is the acronym for Large AtlaNtic Tsunami Exercise, which is carried out annually). The numerical simulation of the propagation and inundation phases is performed with a single integrated model but using different mesh resolutions and nested meshes. Special emphasis is placed on assessing the most exposed coastal areas at Puerto Rico affected by this event. Some comparisons with the MOST tsunami model available at the University of Puerto Rico (UPR) are made. Both models compare well for propagating tsunami waves in open sea, producing very similar results. In near-shore shallow waters, Tsunami-HySEA should be compared with the inundation version of MOST, since the propagation version is limited to deeper waters, both also producing similar results. Nevertheless the most striking difference resides in computational time; Tsunami-HySEA is coded using the advantages of GPU architecture, and can produce a 4 hour simulation in a 60 arc-sec resolution grid for the whole Caribbean Sea in less than 4 min with a single GPU and as fast as 11 seconds with 32 GPUs. When details about the inundation must be simulated, a 1 arc-sec (approximately 30 m) inundation resolution mesh covering all of Puerto Rico, an island with dimensions of 160 km east-west and 56 km north-south, is used, and a three level nested meshes technique implemented. In this case approximately 11 hours of wall clock time are needed for a 2-hour simulation in a single GPU (versus more than a day for the MOST inundation). When domain decomposition techniques are finally implemented by breaking up the computational domain into sub-domains and assigning a GPU to each subdomain (multi-GPU Tsunami-HySEA version), the wall clock time should decrease significantly, allowing high-resolution inundation modeling in just a few hours and at a modest hardware cost compared with present tsunami models.
Article
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A method of second-order accuracy is described for integrating the equations of ideal compressible flow. The method is based on the integral conservation laws and is dissipative, so that it can be used across shocks. The heart of the method is a one-dimensional Lagrangean scheme that may be regarded as a second-order sequel to Godunov's method. The second-order accuracy is achieved by taking the distributions of the state quantities inside a gas slab to be linear, rather than uniform as in Godunov's method. The Lagrangean results are remapped with least-squares accuracy onto the desired Euler grid in a separate step. Several monotonicity algorithms are applied to ensure positivity, monotonicity and nonlinear stability. Higher dimensions are covered through time splitting. Numerical results for one-dimensional and two-dimensional flows are presented, demonstrating the efficiency of the method. The paper concludes with a summary of the results of the whole series “Towards the Ultimate Conservative Difference Scheme.”
Conference Paper
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The GPU implementation of the HySEA numerical model for the simulation of earthquake generated tsunamis is presented. The initial sea surface deformation is computed using the Okada model ([30]). Wave propagation is computed using nonlinear shallow water equations in spherical coordinates, where coastal inundation and run-up are suitable treated in the numerical algorithm. The GPU model implementation allows faster than real time (FTRT) simulation for real large-scale problems. The large speed-ups obtained make HySEA code suitable for its use in Tsunami Early Warning Systems. The Italian TEWS at INGV (Rome) has adopted HySEA GPU code for its National System. The model is verified by hindcasting the wave behaviour in several benchmark problems.
Article
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The coastal states and territories of the United States (US) are vulnerable to devastating tsunamis from near-field or far-field coseismic and underwater/subaerial landslide sources. Following the catastrophic 2004 Indian Ocean tsunami, the National Tsunami Hazard Mitigation Program (NTHMP) accelerated the development of public safety products for the mitigation of these hazards. In response to this initiative, US coastal states and territories speeded up the process of developing/enhancing/adopting tsunami models that can be used for developing inundation maps and evacuation plans. One of NTHMP’s requirements is that all operational and inundation-based numerical (O&I) models used for such purposes be properly validated against established standards to ensure the reliability of tsunami inundation maps as well as to achieve a basic level of consistency between parallel efforts. The validation of several O&I models was considered during a workshop held in 2011 at Texas A&M University (Galveston). This validation was performed based on the existing standard (OAR-PMEL-135), which provides a list of benchmark problems (BPs) covering various tsunami processes that models must meet to be deemed acceptable. Here, we summarize key approaches followed, results, and conclusions of the workshop. Eight distinct tsunami models were validated and cross-compared by using a subset of the BPs listed in the OAR-PMEL-135 standard. Of the several BPs available, only two based on laboratory experiments are detailed here for sake of brevity; since they are considered as sufficiently comprehensive. Average relative errors associated with expected parameters values such as maximum surface amplitude/runup are estimated. The level of agreement with the reference data, reasons for discrepancies between model results, and some of the limitations are discussed. In general, dispersive models were found to perform better than nondispersive models, but differences were relatively small, in part because the BPs mostly featured long waves, such as solitary waves. The largest error found (e.g., the laboratory experiment case of a solitary wave on a simple beach) was 10 % for non-breaking wave conditions and 12 % for breaking conditions; these errors are equal or smaller than the thresholds (10 % and 20 %, respectively) defined by the OAR-PMEL-135 for predicting the surface profile; hence, all models examined here are deemed acceptable for inundation mapping purposes.
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Shallow water models are frequently used to simulate ocean or coastal circulation or tsunami wave propagation. But these models are seldom used to explicitely reproduce for example tsunami wave run-up into coast. In Vázquez-Cendón (1999) a finite volume numerical scheme with upwinding of the source terms. This numerical model has good properties as well-balance, but do not treat correctly wet/dry fronts, as it produces negatives values of the thickness of the fluid layer and stationary solutions corresponding to water at rest including wet/dry fronts are not exactly solved. In Brufau et al. (2002) and Castro et al. (2005) several variants of this numerical scheme have been proposed that partially solve these difficulties. Finally, in Castro et al. (2006) a new variant is proposed, where a Nonlinear Riemann Problem is considered at each intercell instead of a Linear one. In this work we use the implementation of dry/wet for shallow water models proposed in this latter paper which allows us to reproduce coastal inundation and water retrainment once the impact wave passes over. The run-up model has been tested for simple test cases and geometries as in complex, real cases, as the Lituya Bay 1958 megatsunami.
Article
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The Method of Splitting Tsunamis (MOST) model adapted by National Oceanic and Atmospheric Administration (NOAA) for tsunami forecasting operations is praised for its computational efficiency, associated with the use of splitting technique. It will be shown, however, that splitting the computations between x and y directions results in specific sensitivity to the treatment of land-water boundary. Slight modification to the reflective boundary condition in MOST caused an appreciable difference in the results. This is demonstrated with simulations of the Tohoku-2011 tsunami from the source earthquake to Monterey Bay, California, and in southeast Alaska, followed by comparison with tide gage records. In the first case, the better representation of later waves (reflected from the coasts) by the modified model in a Pacific-wide simulation resulted in twice as long match between simulated and observed tsunami time histories at Monterey gage. In the second case, the modified model was able to propagate the tsunami wave and approach gage records at locations within narrow channels (Juneau, Ketchikan), to where MOST had difficulty propagating the wave. The modification was extended to include inundation computation. The resulting inundation algorithm (Cliffs) has been tested with the complete set of NOAA-recommended benchmark problems focused on inundation. The solutions are compared to the MOST solutions obtained with the version of the MOST model benchmarked for the National Tsunami Hazard Mitigation Program in 2011. In two tests, Cliffs and MOST results are very close, and in another two tests, the results are somewhat different. Very different regimes of generation/disposal of water by Cliffs and MOST inundation algorithms, which supposedly affected the benchmarking results, have been discussed.
Article
We present a class of fast first-order finite volume solvers, called PVM (polynomial viscosity matrix), for balance laws or, more generally, for nonconservative hyperbolic systems. They are defined in terms of viscosity matrices computed by a suitable polynomial evaluation of a Roe matrix. These methods have the advantage that they only need some information about the eigenvalues of the system to be defined, and no spectral decomposition of a Roe matrix is needed. As a consequence, they are faster than the Roe method. These methods can be seen as a generalization of the schemes introduced by P. Degond et al. [C. R. Acad. Sci., Paris, Sér. I, Math. 328, No. 6, 479–483 (1999; Zbl 0933.65101)] for balance laws and nonconservative systems. The first-order path-conservative methods to be designed here are intended to be used as the basis for higher-order methods for multidimensional problems. In this work, some well-known solvers, such as Rusanov, Lax-Friedrichs, FORCE (see [E. F. Toro and S. J. Billett, IIMA J. Numer. Anal. 20, No. 1, 47–79 (2000; Zbl 0943.65100); M. J. Castro et al., Math. Comput. 79, No. 271, 1427–1472 (2010; Zbl 05776273)]), GFORCE (see [E. F. Toro and V. A. Titarev, J. Comput. Phys. 216, No. 2, 403-429 (2006; Zbl 1097.65091)]), and HLL (see [A. Harten, P. D. Lax and B. van Leer, SIAM Rev. 25, 35–61 (1983; Zbl 0565.65051)]), are redefined under this form, and then some new solvers are proposed. Finally, some numerical tests are presented, and the performances of the numerical schemes are compared with each others and with the Roe scheme for the 1D and 2D two-fluid flow model of E. B. Pitman and L. Le [Philos. Trans. R. Soc. Lond., Ser. A, Math. Phys. Eng. Sci. 363, No. 1832, 1573–1601 (2005; Zbl 1152.86302)].