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Boletín Geológico, 50(2), 2023
https://doi.org/10.32685/0120-1425/bol.geol.50.2.2023.697
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Received: December 29, 2022
Revision received: August 10, 2023
Accepted: August 14, 2023
Published online: August 16, 2023
Data article
Moment tensor and focal mechanism
data of earthquakes recorded by
Servicio Geológico Colombiano from
2014 to 2021
Datos de tensor de momento y mecanismo focal de sismos
registrados por el Servicio Geológico Colombiano desde 2014
hasta 2021
Viviana
Dionicio
1
,
Patricia
Pedraza García
1
,
Esteban
Poveda
1
1. Red Sismológica Nacional de Colombia, Servicio Geológico Colombiano, Bogotá, Colombia.
Corresponding author: Viviana Dionicio, ldionicio@sgc.gov.co
ABST RA CT
The Servicio Geológico Colombiano shows the seismic moment tensors and focal mechanisms calculated for earthquakes located
in the national territory and border regions from 2014 to 2021. These solutions were obtained using different methods based on
waveform inversion (SWIFT, SCMTV, W phase, and ISOLA) and first-motion polarities (FPFIT). This information is organized
in a database and is available to the public through a web page that can be searched by date, circular area, or quadrant. The
moment tensor centroid solutions are fundamental to understanding the fault's geometry, the seismic source generated by an
earthquake, its magnitude, and the energy released. Likewise, thanks to this information it is possible to make interpretations
about tectonic plates, Earth's crust stress analysis and its dynamics, kinematic and dynamic source models, active faults analysis,
and tsunamigenic potential of earthquakes, among other aspects.
Keywords:
Seismic Moment Tensor, Focal Mechanism, SWIFT, SCMTV, W phase, ISOLA, first-motion polarities, seismology.
RESUM EN
El Servicio Geológico Colombiano presenta los tensores de momento sísmico y mecanismos focales calculados para sismos
localizados en el territorio nacional y regiones fronterizas desde 2014 hasta 2021. Estas soluciones se obtuvieron usando diferen-
tes métodos basados en inversión de formas de onda (SWIFT, SCMTV, Fase W e ISOLA) y polaridades de primeros arribos
(FPFIT). Esta información se ha organizado en una base de datos y se ha dispuesto al público mediante una página web por medio
de la cual se pueden hacer búsquedas por fechas, área circular o cuadrante. Las soluciones del centroide del tensor de momento
son fundamentales para comprender la geometría de la falla, la fuente sísmica que produce un sismo, su magnitud, y la energía
liberada por el mismo. Igualmente, gracias a esta información es posible hacer interpretaciones sobre la tectónica de placas,
análisis de esfuerzos de la corteza terrestre y su dinámica, modelos dinámicos y cinemáticos de la fuente, análisis de fallas activas
y potencial tsunamigénico de sismos, entre otros aspectos.
Palabras clave: Tensor de Momento Sísmico, mecanismo focal, SWIFT, SCMTV, Fase W, ISOLA, polaridades de primeros arribos, sismología.
Citation: Dionicio, V. Pedraza-García, P. & Poveda, E. (2023). Moment tensor and focal mechanism data of earthquakes recorded by Servicio Geológico Colombi-
ano from 2014 to 2021. Boletín Geológico, 50(2). https://doi.org/10.32685/0120-1425/bol.geol.50.2.2023.694
2
B o le tí n G e o ló gi co 50( 2)
Dionicio / Pedraza-García / Poveda
1.
INTRODUCTION
The Servicio Geológico Colombiano (SGC) made great efforts
to calculate earthquakes' Seismic Moment Tensor (SMT) and
Focal Mechanism (FM) in recent years, using different methods
of waveform inversion and first-motion polarities, to have infor-
mation that allows us to better understand the country seismic
sources. The variety of methodologies is mainly due to the Na-
tional Seismological Network of Colombia (RSNC, from its ab-
breviation in Spanish) evolution, station densification in the ter-
ritory, as well as its instrumental and technological updating in
the data acquisition and processing software. Also, having a va-
riety of methodologies for SMT calculation allows for control-
ling the solution's quality and stability, turning the SGC earth-
quake catalogs into self-sustainable tools over time.
The Servicio Geológico Colombiano is the official entity
that provides information on earthquakes in Colombian territory
and is part of the National System for Disaster Risk Manage-
ment. Therefore, through the RSNC, the SGC monitors seismic-
ity in real-time permanently twenty-four hours a day, seven days
a week.
Thus, when an earthquake is recorded, the information as-
sociated is immediately calculated, including seismic moment
tensor and focal mechanism for those earthquakes that allow it.
This information is stored in a database and is available to the
public in real-time. This article presents the SMT and FM from
2014 to 2021, but we clarify that this database is constantly up-
dated accounting for the SGC mission.
This database can be used by any researcher interested in
geophysics, tectonics, or seismology to do their processing,
modeling, or interpretation. Although they allow scientific anal-
ysis, they are also important tools for risk management plans and
land use planning. Therefore, these data became of great impact
on the scientific community as well as decision-makers.
Furthermore, this database extends and enhances efforts
historically made determining focal mechanisms in the region at
both the national and local levels by other researchers such as
Molnar and Sykes, 1969; Kafka and Weidner, 1981; Pennington,
1981; Audemard et al, 2005; Cortés and Angelier, 2005; Palma
et al., 2010; Dicelis et al., 2016; Gómez-Alba et al., 2016; Poli
et al., 2016; Posada et al., 2017; Yoshimoto et al., 2017;
Monsalve-Jaramillo et al., 2018; Chang et al., 2019; Londoño et
al. 2019; Poveda et al., 2022; Quintanar et al., 2022; Tary et al.,
2022; Bishop et al., 2023.
Although there are international SMT catalogs with events
information in Colombia, like Global Centroid Moment Tensor
Catalog (Dziewonski, et al., 1981 and Ekström, et al., 2012), the
German GEOFON project (Hanka and Kind, 1994; Saul et al.,
2011; GFZ, 2023), from the German Research Centre for Geosci-
ences (GFZ) and the United States Geological Survey
(https://www.usgs.gov/programs/earthquake-hazards), among
others, the SGC can calculate a larger number of solutions since
installed seismological stations quality and distribution in the
country allow better stability to solutions for earthquakes with
moderate magnitudes.
The SGC also has some catalogs with seismicity recorded in
the country, which may be useful for the reader: Viewer of seis-
mological information (Visor información sismológica) in real-
time at: https://www.sgc.gov.co/sismos, Seismicity catalog
(Catálogo de sismicidad) at: http://bdrsnc.sgc.gov.co/pagi-
nas1/catalogo/index.php, Accelerations catalog (Catálogo de
aceleraciones) at: http://bdrsnc.sgc.gov. co/paginas1/catalogo/in-
dex_rnac.php, Macroseismic intensity data and effects of signifi-
cant earthquakes in Colombia based on historical seismicity stud-
ies (Datos de intensidad macrosísmica y efectos de los sismos sig-
nificativos de Colombia a partir de estudios de sismicidad histó-
rica) at: http://sish.sgc.gov.co/visor/ (Sarabia Gómez et al. 2022),
Integrated Seismic Catalog for Colombia (Catálogo Sísmico Inte-
grado para Colombia), as input or reference to generate hazard
models and characterize seismogenic sources at: https://cat-
alogosismico.sgc.gov.co/visor/index.html (Montejo et al., 2023).
2. DATA DESCRIPTION
Data correspond to seismic moment tensors and focal mechanisms
calculated by the SGC for earthquakes located in the national ter-
ritory and border regions from 2014 to 2021 (Figure 1). The solu-
tions were obtained using different methods based on waveform
inversion and first motion P-waves polarities and systematically
compared with calculated Global Centroid Moment Tensor cata-
log solutions (Dziewonski et al., 1981 and Ekström et al., 2012) to
ensure their quality (Figure 4). Notice the importance of a station
good distribution that records each earthquake to calculate the so-
lutions with those different methods, so the earthquake azimuthal
coverage is as homogeneous as possible.
Moreover, for waveform inversion methods it is necessary to
use broadband stations; since 2008 the SGC started a densification
process and instrumental updating of the National Seismological
Network of Colombia (RSNC), achieving a stable and fairly uni-
form station distribution in 2014, making possible the proper
methodologies implementation for moment tensor calculation and
focal mechanisms
3
Moment tensor and focal mechanism data of earthquakes recorded by Servicio Geológico Colombiano from 2014 to 2021
.
.
Figure 1. Focal mechanisms calculated by the SGC of earthquakes occurred between 2014 and 2021. From each focal mechanism, the user can access the detail of
the moment tensor solutions for each earthquake
A database stores the results and contains the solutions of each
earthquake for the used methods to calculate them (described in
"materials and methods"). At the web page
http://bdrsnc.sgc.gov.co/sismologia1/sismologia/focal_seis-
comp_3/index.html the users can access to focal mechanism and
moment tensor catalog data, the search can be simple (including
only initial and final dates), or, if preferred, with additional ad-
vanced parameters (for example, to select results in a circular geo-
graphic region or latitude-longitude quadrant). As a result of this
search, a list is obtained with seismic events with focal mechanisms
and moment tensors for the selected dates and areas. The table con-
tains: UTC (Universal Time Coordinated) date and time, region,
latitude, longitude, depth, magnitude, location agency, and solu-
tions obtained selected by the used method, showing the focal
mechanism graphical representation. By clicking on it the user can
access further information. The table can be organized by any of its
columns and either download an Excel file with the results or
be represented automatically on a map (Figures 2 and 1).
For each method, are presented the focal mechanism, the
moment tensor solution including the centroid location, mo-
ment, moment magnitude (Mw), depth, nodal planes, principal
axes, and moment tensor, as applicable.
An example of a solution with the SWIFT method (Source
parameter determination based on Waveform Inversion of Fou-
rier Transformed seismograms) is shown in Figure 3. The maps
are also shown with the solution, the waveform matches ob-
tained from the inversion with observed and synthesized seis-
mograms, and the source-time function (the latter is only shown
for the SWIFT method).
Dionicio / Pedraza-García / Poveda
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B o le tí n G e o ló gi co 50( 2)
Figure 2. Input interface to the historical seismicity information system
Figure 3. Results of a moment tensor solution with the SWIFT method calculated by the SGC for the March 23, 2019 earthquake, located in Versalles - Valle del
Cauca, depth 126 km. a) Seismic moment tensor inversion results, b) the waveform matches obtained from the inversion with observed and synthesized seismograms,
c) source time function, d) location map and centroid solution of the seismic moment tensor, e) location map of seismic source and the available stations for the
inversion.
c) d) e)
a) b)
Moment tensor and focal mechanism data of earthquakes recorded by Servicio Geológico Colombiano from 2014 to 2021
S e rv i c io G eo ló gi co Co lo mb i a no
5
3. DATA RELEVANCE
This is the catalog of centroid moment tensor solutions and focal
mechanisms located in Colombia and its border regions from
2014 to 2021 (this catalog is routinely updated by the SGC, so it
contains information from later years), and comprehends the so-
lutions calculated with acceptable quality (variance < 70% usu-
ally).
Unlike other international catalogs, the SGC can calculate a
greater number of solutions considering the distribution and qual-
ity of the seismological stations installed across the country, al-
lowing greater stability in the solutions for earthquakes with mod-
erate magnitudes.
Data can be used by any researcher interested in geophysics,
tectonics, or seismology to do their processing, modeling, or in-
terpretation.
Likewise, they are an important tool for the generation of
risk management and land-use planning plans. The latter, consid-
ering that the information on location, moment magnitude and
seismic source characterization of moderate to large magnitude
earthquakes can be considered in national and regional seismic
hazard maps generation and updating.
4. ACCESS TO DATA
Data on moment tensor and focal mechanism calculated by the
SGC are in a database freely accessible from the institute's web-
site (Table 1).
Figure 4. Mw from GCMT compared to Mw from SGC resulting after moment tensor inversions calculated through different methodologies for the 2014 - 2021
period. Top left SWIFT, top right W phase, bottom left SCMTV, and bottom right ISOLA
Table 1.
Data specifications
Area
Geophysics, seismology, tectonics, geology, geodynamics
Specific subject
area
Seismology
Data type
Table/ Image/ Map / Chart /Figure
How the data
were acquired
Primary data were seismograms from seismological stations ( Seismic event data download (Servicio de descarga
de datos de eventos sísmicos) at http://sismo.sgc.gov.co:8080/). From short-period stations, only the first-motion
polarities data were used (polarities method). From broadband stations, in addition to these, full seismograms
were also used in the seismic inversion methods described in the materials and methods section. Furthermore,
the locations of the earthquakes were used as initial data (Seismic Catalog (Catálogo sísmico) at
http://bdrsnc.sgc.gov.co/paginas1/catalogo/index.php).
Data format
Processing result for focal mechanisms calculation and moment tensor: graphs, figures, and tables.
Parameters for
data collection
Earthquake location, quality of signals and solutions were considered.
Description of
data collection
The database contains all earthquake inversions in the national territory and its borders, for which it was possible
to calculate the moment tensor/focal mechanism with a minimum quality to trust the results.
Location of the
data source
South America/Colombia
Longitude between -90° and -66° and latitude between -7° and 15°.
Data accessibility
http://bdrsnc.sgc.gov.co/sismologia1/sismologia/focal_seiscomp_3/index.html
Dionicio / Pedraza-García / Poveda
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B o le tí n G e o ló gi co 50( 2)
5.
M
ATERIALS AND METHODS
The moment tensors and focal mechanisms were calculated us-
ing different methods:
5.1 SWIFT (Source parameter determination based on
Waveform Inversion of Fourier Transformed seismograms),
proposed by Nakano et al. (2008): It is a waveform inversion
method to estimate both the moment function and the centroid
of the moment tensor of an earthquake quickly and routinely.
For this method, the waveform inversion is carried out in the
frequency domain to obtain the momentum function faster than
when solving in the time domain. A pure double-couple (also
called double-pair) source mechanism is assumed to stabilize
the solution. The fault and slip orientations are estimated by a
grid search respect to strike, dip and slip angles. The time do-
main moment function is obtained from the inverse Fourier
transform of frequency components determined by the inver-
sion. The source location is determined by a grid search using
adaptive grid spacing, which is gradually reduced at each step
of the search.
5.2 SCMTV (SeisComP Moment Tensor inVersion), a
module implemented in the SeisComP3 software package
(Helmholtz Centre Potsdam GFZ German Research Centre for
Geosciences and gempa GmbH, 2008;
https://docs.gempa.de/mt/current/apps/scmtv.html#methodology;
https://gfzpublic.gfz-potsdam.de/pubman/faces/ViewItemFull-
Page.jsp?itemId=item_108170). This algorithm calculates the
deviatoric part of the momentum tensor assuming a point
source. For this purpose, it inverts the entire waveform (body
waves, surface waves, and the W phase). Phase type selection
is based on magnitude (for filter selection) and epicentral dis-
tance of seismic event (for window calculation upon theoretical
arrival times). The inversion methodology is based on Minson
and Dreger's (2008) proposal.
5.3 W phase, algorithm proposed by Kanamori and Rivera
(2008): It inverts the W phase (Kanamori, 1993), a long period
signal arriving before the S-wave, which can be interpreted as
the superposition of the fundamental first, second, and third
overtones of spheroidal modes or Rayleigh waves and has a
group velocity of 4.5 to 9 km s−1 in a period range of 100-1000
s. Amplitudes of long-period waves best represent the tsunami
potential of an earthquake. Due to the W phase rapid group ve-
locity, most of the energy is contained within a short time win-
dow after the P-wave arrival. The time domain deconvolution
method is used to extract the W phase of the vertical component
of broadband records from seismic networks, and a linear inver-
sion is performed using a point source to determine Mw and the
source mechanism.
5.4 ISOLA (ISOlated Asperities), a software package de-
veloped by Sokos and Zahradnik (2008, 2013): Performs wave-
form inversions to find source parameters; is based on FORTRAN
codes and provides an easy-to-use MATLAB graphical user inter-
face (GUI) (www.mathworks.com/products/MATLAB). It allows
the waveform iterative deconvolution inversion (Kikuchi and
Kanamori, 1991) for regional and local events, both for single- and
multiple-point-source. The moment tensor is obtained through a
least-squares inversion, while the position and origin time of point
sources are searched on a grid. Computational options include in-
version to recover the full moment tensor (MT), the deviatoric
MT, and the pure double-coupled MT. Finite-extent source inver-
sions can also be obtained by prescribing a priori the double-cou-
pled mechanism (to remain homogeneous over the fault plane);
Green's functions are obtained by including the near-field terms.
5.5 Polarities: The focal mechanism is computed using the
FPFIT program (Reasenberg and Oppenheimer, 1985). It finds the
double-coupled fault plane solution (source model) that best fits a
given set of observed first-motion polarities for an earthquake. The
inversion is done through a two-stage grid search procedure,
which identifies the source model by minimizing a normalized
weighted sum of first-motion polarity discrepancies. The minimi-
zation incorporates two weighting factors: data estimated variance
and the absolute value of the theoretical P-wave radiation ampli-
tude (Aki and Richards, 1980). The latter weighting adds a higher
weight to observations near radiation lobes, and a lower weight to
those close to nodal planes. For each double-couple source model
obtained, FPFIT estimates uncertainty model parameters (strike,
dip, and rake) by calculating their standard deviation.
Afterward, a uniformly distributed set of solutions is calcu-
lated that falls into the estimated uncertainty range. This set is used
in the FPPLOT display program (https://www.usgs.gov/soft-
ware/fpfit-fpplot-and-fppage) via SEISAN software (Ottemöller
et al, 2021) to define the orientation range of the P and T axes
graphically based on data.
The National Seismological Network of Colombia has im-
proved over time in both seismological instrumentation and data
acquisition and processing systems. From 2014 to 2017 the SGC
used SEISAN as data processing system, so the FPFIT software
was used for focal mechanisms calculation; likewise, to calculate
moment tensors mainly focused on tsunami warnings for large
earthquakes, the W phase method was implemented calculating
automatically SMT and sending the solutions by emails. Moreo-
ver, by the same period, the ISOLA method was used to calculate
moment tensor for earthquakes with moderate to large magni-
tudes, but was not automated as the waveforms were processed
manually.
Moment tensor and focal mechanism data of earthquakes recorded by Servicio Geológico Colombiano from 2014 to 2021
S e rv i c io G eo ló gi co Co lo mb i a no
7
Simultaneously, between 2016 and 2017, SeisComP soft-
ware for data acquisition, processing, publication, and dissemi-
nation was installed, configured, and tested, with the great ad-
vantage of everything integrated, going into production in March
2018. This system incorporates the SCMTV method for moment
tensor inversion, hence it was incorporated as a methodology for
real-time processing at the SGC. Likewise, in 2015 the SGC
along with other Colombian institutions and the Japan Interna-
tional Cooperation Agency on behalf of different Japanese enti-
ties, jointly initiated a SATREPS (Science and Technology Re-
search Partnership for Sustainable Development) project entitled
"Project for application of state of the art technologies to
strengthen research and response to seismic, volcanic and tsu-
nami events, and enhance risk management” with an initial du-
ration of 5 years extended for 2 more years. Under this project,
was installed, configured, tested, and put into production SWIFT
software for moment tensor calculation, focused on obtaining
seismic source information for moderate to strong earthquakes
in a reliable and fast way, with a methodology also integrated
with SeisComP and everything was articulated to fully link it to
SGC information dissemination system.
Currently, the Polarities method is not routinely used, be-
cause it is less stable than waveform inversions and is not inte-
grated with our data acquisition and processing software; for
waveform inversion methods these polarities are considered.
The ISOLA method is used only for some very representative
earthquakes in the country or for detailed seismic source studies,
but is not routinely used due to the longer processing time; how-
ever, the Gisola software (Triantafyllis et al. 2021), based on the
same methodology as ISOLA, but automates all the data pro-
cessing, is currently tested; once it is in production, likely the
database information of this article will be updated with those
results. W phase, SWIFT, and SCMTV methods work in real-
time routinely, automatically, and the results are reviewed by an
expert before publishing reports as a fundamental information
provided by the SGC to the Risk Management System and to the
public.
The SGC considers important to have different calculation
methods for seismic moment tensors, not only because depend-
ing on the methodology results can be obtained for lower mag-
nitudes, but also to control the quality and stability of solutions
for moderate to large magnitude earthquakes, which are ones
that could have the greatest impact on the Colombian territory.
Comparison of different solutions demonstrates the consistency
of the results and allows the various SGC seismic catalogs to be
self-sustaining, especially in real-time, since solutions from
other international catalogs sometimes take longer to be pub-
lished.
For all SMT methodologies, the moment magnitude is calcu-
lated using the ratio of scalar moment to moment magnitude cited
by Kanamori (1977); Hanks and Kanamori (1979) and Bormann
et al. (2013):
Mw = (log M0 – 9.1) /1.5 = (2/3) (log M0 – 9.1) in SI o Mw = (2/3)
(log M0 – 16.1) CGS units,
Personal communications with authors of the methodologies con-
firmed that each of them uses the following ratios: SWIFT imple-
ments Mw = (log M0 – 9.1)/1.5, W phase implements Mw = (2/3)
(log M0 – 16.1), ISOLA implements Mw = (2/3) (log M0 – 9.1) y
SCMTV implements Mw = (log M0 – 9.1)/1.5 = (2/3) (log M0 –
9.1).
6.
U
SE OF THE DATA
Seismic moment tensor centroid solutions are fundamental to un-
derstanding fault geometry, the seismic source producing an
earthquake, its magnitude, and the energy released (e.g., Stein and
Wysession, 2003). Furthermore, using this information, interpre-
tations of plate tectonics, crustal dynamic and stress analysis, kin-
ematic and dynamic source models, and active fault analysis,
among others, are possible (e.g., Shearer, 2019). Likewise, based
on this data, it is possible to have information on the tsunamigenic
potential of an earthquake and thus assess to alert communities
for a possible evacuation (Tilling, 2022).
ACKNOWLEDGEMENTS
The authors thank the staff of the Colombian National Seismo-
logical Network of the Servicio Geológico Colombiano who
worked with so much effort and dedication to have excellent qual-
ity data from its acquisition, processing, and publication. This re-
search is a contribution of Servicio Geológico Colombiano, Na-
tional Seismological Network of Colombia, project "Monitoreo e
Investigación de la Actividad sismológica del territorio colom-
biano" (number 1001688). The authors thank the anonymous re-
viewers for their comments, which greatly improve this article by
giving clarity and relevance to the topic.
CONFLICT OF INTEREST
The authors declare that they have no financial interests or com-
peting personal relationships that could affect the work reported in
this paper.
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B o le tí n G e o ló gi co 50( 2)
REFERENCES
Aki, K. & Richards, P. G. (1980). Quantitative seismology,
Theory and methods, Volume 1. W.H. Freeman and Co.
Audemard, F. A., Romero, G., Rendon, H. & Cano, V. (2005).
Quaternary fault kinematics and stress tensors along the
southern Caribbean from fault-slip data and focal mecha-
nism solutions. Earth-Science Reviews, 69 (3-4), 181-233.
https://doi.org/10.1016/j.earscirev.2004.08.001
Bishop, B. T., Cho, S., Warren, L., Soto-Cordero, L., Pedraza,
P., Prieto, G. A., & Dionicio, V. (2023). Oceanic intraplate
faulting as a pathway for deep hydration of the lithosphere:
Perspectives from the Caribbean. Geosphere, 19(1), 206-
234. https://doi.org/10.1130/GES02534.1
Bormann, P., Wendt, S. & DiGiacomo, D. (2013). Seismic
Sources and Source Parameters. In Bormann, P. (Ed.),
New manual of seismological observatory practice 2
(NMSOP2), Potsdam. Deutsches GeoForschungsZentrum
GFZ, 1-259. https://doi.org/10.2312/GFZ.NMSOP-2_ch3
Chang, Y., Warren, L. M., Zhu, L. & Prieto, G. A. (2019).
Earthquake focal mechanisms and stress field for the inter-
mediate-depth Cauca Cluster, Colombia. Journal of Geo-
physical Research: Solid Earth, 124 (1), 822-836.
https://doi.org/10.1029/2018JB016804
Cortés, M. & Angelier, J. (2005). Current states of stress in the
northern Andes as indicated by focal mechanisms of earth-
quakes. Tectonophysics, 403(1–4), 29–58.
https://doi.org/10.1016/j.tecto.2005.03.020
Dicelis, G., Assumpção, M., Kellogg, J., Pedraza, P. & Dias,
F. (2016). Estimating the 2008 Quetame (Colombia) earth-
quake source parameters from seismic data and InSAR
measurements. Journal of South American Earth Sciences,
72, 250-265, ISSN 0895-9811,
https://doi.org/10.1016/j.jsames.2016.09.011.
Dziewonski, A. M., Chou T. A. & Woodhouse, J. H. (1981).
Determination of earthquake source parameters from
waveform data for studies of global and regional seismic-
ity. Journal of Geophysical Research , 86, 2825-2852.
doi:10.1029/JB086iB04p02825
Ekström, G., Nettles, M. & Dziewonski, A. M. (2012). The
global CMT project 2004-2010: Centroid-moment tensors
for 13,017 earthquakes. Phys. Earth Planet. Inter., 200-
201, 1-9. doi:10.1016/j.pepi.2012.04.002
GFZ (2023). GEOFON Moment Tensor Solutions.
https://doi.org/10.17616/R36613 https://geofon.gfz-pots-
dam.de/old/eqinfo/list.php?mode=mt
Gómez-Alba, S., Fajardo-Zarate, C. E., & Vargas, C. A.
(2016). Stress field estimation based on focal mechanisms
and back projected imaging in the Eastern Llanos Basin (Co-
lombia). Journal of South American Earth Sciences, Volume
71, 2016, 320-332, ISSN 0895-9811.
https://doi.org/10.1016/j.jsames.2015.08.010.
Hanka, W. & Kind, R. (1994). The GEOFON Program. Annali
di Geofisica, 37 (5), 1060-1065. https://doi.org/10.4401/ag-
4196
Hanks, T. C. & Kanamori, H. (1979). A moment magnitude
scale. Journal of Geophysical Research B: Solid Earth, 84
(B5), 2348–2350.
https://doi.org/10.1029/JB084iB05p02348
Helmholtz Centre Potsdam GFZ German Research Centre for
Geosciences and gempa GmbH (2008). The SeisComP seis-
mological software package. GFZ Data Services.
doi:10.5880/GFZ.2.4.2020.003
Kafka, A. L. & Weidner, D. J. (1981). Earthquake focal mecha-
nisms and tectonic processes along the southern boundary of
the Caribbean Plate. Journal of Geophysical Research: Solid
Earth, 86 (B4) 2877-2888.
https://doi.org/10.1029/JB086iB04p02877
Kanamori H. (1977). The energy release in great earthquakes.
Journal of Geophysical Research, 82 (20), 2981–2987.
Kanamori, H. (1993). W phase. Geophysical Research Letters,
20 (16), 1691-1694. https://doi.org/10.1029/93GL01883
Kanamori, H. & Rivera, L. (2008). Source inversion of W phase:
Speeding up seismic tsunami warning. Geophysical Journal
International, 175(1), 222–238.
https://doi.org/10.1111/j.1365-246X.2008.03887.x
Kikuchi, M. & Kanamori, H. (1991). Inversion of complex body
waves - III. Bulletin of the Seismological Society of America,
81(6), 2335–2350. https://doi.org/10.1785/bssa0810062335
Londoño, J. M., Quintero, S., Vallejo, K., Muñoz, F. & Romero,
J. (2019). Seismicity of Valle Medio del Magdalena basin,
Colombia. Journal of South American Earth Sciences, 92,
565-585, ISSN 0895-9811.
https://doi.org/10.1016/j.jsames.2019.04.003
Minson, S. E. & Dreger, D. S. (2008). Stable inversions for com-
plete moment tensors. Geophysical Journal International,
174(2), 585–592. https://doi.org/10.1111/j.1365-
246X.2008.03797.x
Molnar, P. & Sykes, L. (1969) Tectonics of the Caribbean and
Middle America regions from focal mechanisms and seis-
micity. Geological Society of America Bulletin, 80 (9):
1639–1684. https://doi.org/10.1130/0016-
7606(1969)80[1639:TOTCAM]2.0.CO;2
Monsalve-Jaramillo, H., Valencia-Mina, W., Cano-Saldaña, L.
& Vargas, C. A. (2018). Modeling subduction earthquake
sources in the central-western region of Colombia using
Moment tensor and focal mechanism data of earthquakes recorded by Servicio Geológico Colombiano from 2014 to 2021
S e rv i c io G eo ló gi co Co lo mb i a no
9
waveform inversion of body waves. Journal of Geodynam-
ics, 116, 47–61. https://doi.org/10.1016/j.jog.2018.02.005
Montejo, J., Arcila, M., & Zornosa, D. (2023). Integrated Seis-
mic Catalog for Colombia. Boletín Geológico, 50(1).
https://doi.org/10.32685/0120-
1425/bol.geol.50.1.2023.665
Nakano, M., Kumagai, H. & Inoue, H. (2008). Waveform in-
version in the frequency domain for the simultaneous de-
termination of earthquake source mechanism and moment
function. Geophysical Journal International, 173(3),
1000–1011. https://doi.org/10.1111/j.1365-
246X.2008.03783.x
Ottemöller, L., Voss, P. H. & Havskov J. (2021). SEISAN
earthquake analysis software for Windows, Solaris, Linux
and Macosx (12.0). University of Bergen. ISBN 978-82-
8088-501-2, URL http://seisan.info
Palma, M.; Audemard, F.A. & Romero, G. (2010). Nuevos
mecanismos focales para Venezuela y áreas vecinas 2005-
2008: importancia de la densificación y distribución de la
Red Sismológica Nacional. Revista Técnica de la Facultad
de Ingeniería Universidad del Zulia, 33 (2), 108-121.
https://ve.scielo.org/scielo.php?script=sci_art-
text&pid=S0254-07702010000200002
Pennington, W.D. (1981). Subduction of the Eastern Panama
Basin and seismotectonics of northwestern South America.
Journal of Geophysical Research - Solid Earth, 86 (B11),
10753-10770. https://doi.org/10.1029/JB086iB11p10753
Poli, P., Prieto, G. A., Yu, C.Q., Florez, M., Agurto-Detzel, H.,
Mikesell, T.D., Chen, G., Dionicio V. & Pedraza, P.
(2016). Complex rupture of the M6. 3 2015 March 10 Bu-
caramanga earthquake: evidence of strong weakening pro-
cess. Geophys. J. Int. 205(2), 988-994.
Posada, G., Monsalve, G. & Abad, A. M. (2017). Focal mech-
anism construction in the north of the Colombian Central
Cordillera from record the National Seismological Net-
work of Colombia. Boletín de Ciencias de la Tierra, 42,
36-44. https://doi.org/10.15446/rbct.n42.57160
Poveda, E., Pedraza, P., Velandia, F., Mayorga, E., Plicka, V.,
Gallovič, F. & Zahradník, J. (2022). 2019 MW 6.0 Mesetas
(Colombia) earthquake sequence: Insights from integrating
seismic and morphostructural observations. Earth and
Space Science. https://doi.org/10.1029/2022ea002465
Quintanar, L., Molina-García, S. P. & Espíndola, V. H. (2022)
The Gorgona island, Colombia, earthquake of 10 Septem-
ber 2007 (MW 6.8); rupture process and implications on the
seismic hazard in the region, Journal of South American
Earth Sciences, 118, 103941, ISSN 0895-9811.
https://doi.org/10.1016/j.jsames.2022.103941
Reasenberg, P. & Oppenheimer, D. (1985). FPFIT, FPPLOT and
FPPAGE: Fortran computer programs for calculating and
displaying earthquake fault-plane solutions. U.S. Geological
Survey, Open-File Report, 85–739.
Sarabia Gómez, A. M., Barbosa Castro, D. R. & Arcila Rivera,
M. M. (2022). Macroseismic intensity data and effects of sig-
nificant earthquakes in Colombia from historical seismicity
studies. Boletín Geológico, 49(2), 5-14, 2022.
https://doi.org/10.32685/0120-1425/bol.geol.49.2.2022.638
Saul, J., Becker, J. & Hanka, W. (2011). Global moment tensor
computation at GFZ Potsdam. American Geophysical Un-
ion, Fall Meeting 2011, Abstract ID S51A-2202.
https://ui.adsabs.har-
vard.edu/abs/2011AGUFM.S51A2202S/abstract
Shearer, P. (2019). Introduction to seismology (Third Edition).
Cambridge University Press, Cambridge, 442 pp.
doi:10.1017/9781316877111
Sokos, E. N. & Zahradnik, J. (2008). ISOLA a Fortran code and
a Matlab GUI to perform multiple-point source inversion of
seismic data. Computers and Geosciences, 34(8).
https://doi.org/10.1016/j.cageo.2007.07.005
Sokos, E. & Zahradník, J. (2013). Evaluating centroid-moment-
tensor uncertainty in the new version of ISOLA software.
Seismological Research Letters, 84(4), 656–665.
https://doi.org/10.1785/0220130002
Stein S. & Wysession M. (2003). An introduction to seismology
earthquakes and earth structure. Blackwell Pub.
Tary, J. B., Mojica Boada, M. J., Vargas, C. A., Montaña Mo-
noga, A. M., Naranjo-Hernandez, D. F. & Quiroga, D. E.
(2022). Source characteristics of the MW 6 Mutatá earth-
quake, Murindo seismic cluster, northwestern Colombia.
Journal of South American Earth Sciences, 115, 103728,
ISSN 0895-9811.
https://doi.org/10.1016/j.jsames.2022.103728
Tilling, R. (2022). Complexity in tsunamis, volcanoes, and their
hazards. A volume in the encyclopedia of complexity and sys-
tems science (Second Edition). Springer.
Triantafyllis, N., Venetis, I. E., Fountoulakis, I., Pikoulis, E.-V.,
Sokos, E. & Evangelidis, C. P. (2021). Gisola: A High-Per-
formance Computing Application for Real-Time Moment
Tensor Inversion. Seismological. Research Letters.
https://doi.org/10.1785/0220210153
Yoshimoto, M., Kumagai, H., Acero, W., Ponce, G., Vásconez,
F., Arrais, S., Ruiz, M., Alvarado, A., Pedraza–García, P.,
Dionicio, V., Chamorro, O., Maeda, Y. & Nakano M. (2017).
Depth–dependent rupture mode along the Ecuador–Colom-
bia subduction zone. Geophysical Research Letters, 44(5),
2203–2210. https://doi.org/10.1002/2016GL071929.
