Michael Bevis

• Ph.D.
• Professor at The Ohio State University

The Greenland ice sheet (GrIS) is at present the largest single contributor to global-mass-induced sea-level rise, primarily because of Arctic amplification on an increasingly warmer Earth1–5. However, the processes of englacial water accumulation, storage and ultimate release remain poorly constrained. Here we show that a noticeable amount of the...

The Brillouin sphere is defined as the smallest sphere, centered at the origin of the geocentric coordinate system, that incorporates all the condensed matter composing the planet. The Brillouin sphere touches the Earth at a single point, and the radial line that begins at the origin and passes through that point is called the singular radial line....

Greenland's bedrock responds to ongoing ice loss with an elastic vertical land motion (VLM) that is measured by Greenland's Global Navigation Satellite System (GNSS) Network (GNET). The measured VLM also contains other contributions, including the long‐term viscoelastic response of the Earth to the deglaciation of the last glacial period. Greenland...

In this paper, we propose a fully coupled two-phase poroelastic deformation theory for a spherically-layered and self-gravitating Earth. The Earth model consists of a solid inner core, a fluid outer core, and poroelastic mantle and crust. The boundary-value problems are posed in the Laplace-transformed domain using the spherical system of vector fu...

From cadastre and engineering to scientific uses, many practical applications of Geodetic Reference Frames (GRFs) require site coordinates in a reference or conventional epoch (CE) that is different from the observation epoch. Because the Earth is dynamic and coordinates in a GRF are not static, when combining georeferenced features measured at dif...

Climate oscillations with seasonal and longer periods drive surface water cycles and quasi-cycles at regional and global scales. Changes in terrestrial water storage produce responses in the Earth's gravitational field and crustal deformation. Here, we use techniques from the Global Positioning System (GPS) and the Gravity Recovery and Climate Expe...

Spherical harmonic expansions (SHEs) play an important role in most of the physical sciences, especially in physical geodesy. Despite many decades of investigation, the large order behavior of the SHE coefficients, and the precise domain of convergence for these expansions, have remained open questions. These questions are settled in the present pa...

For a singleton planet, P, with gravitational potential, V, we show that for each ɛ > 0, there exists a planet P′ with gravitational potential V′, with (P′, V′) “ɛ-close” to (P, V) (in an appropriate C⁰-sense), for which the spherical harmonic expansion of V′ does not extend more than a distance ɛ below the Brillouin sphere of P′.

Plain Language Summary A wide range of sensors and methods have been used to study the changes of the Greenland Ice Sheet, including satellite gravimetry, altimetry, and the input‐output method. Here, we present a novel fourth method to estimate dynamic ice loss of Greenland's three largest outlet glaciers: Jakobshavn Isbræ, Kangerlussuaq Glacier,...

We present a theory of modern, thermally-induced deformation in a realistic Earth. The heat conduction equation is coupled with standard elastic deformation theory to construct a boundary-value problem comprised of eighth-order differential equations. The accurate and stable dual variable and position propagating matrix technique is introduced to s...

We derive exact asymptotic solutions for the static deformation due to a concentrated or point-like dislocation in a spherical, layered, elastic, isotropic and self-gravitating Earth. The exact asymptotic solutions are quite general and can provide the dislocation Love numbers on the Earth's surface, near the dislocation or ‘source’, and close to a...

The Greenland Ice Sheet is the largest land ice contributor to sea level rise. This will continue in the future but at an uncertain rate and observational estimates are limited to the last few decades. Understanding the long-term glacier response to external forcing is key to improving projections. Here we use historical photographs to calculate ic...

Spherical harmonic expansions (SHEs) play an important role in most of the physical sciences, especially in physical geodesy. Despite many decades of investigation, the large order behavior of the SHE coefficients, and the precise domain of convergence for these expansions, have remained open questions. These questions are settled in the present pa...

For a singleton planet $P$ with gravitational potential $V$, we show that for each $\varepsilon > 0$ there exists a planet $P'$ with gravitational potential $V'$, with $(P',V')$ "$\varepsilon$-close" to $(P,V)$ (in an appropriate $C^0$-sense) for which the spherical harmonic expansion of $V'$ does not extend more than a distance $\varepsilon$ below...

S U M M A R Y In this paper, we derive analytical solutions for the dislocation Love numbers (DLNs) and the corresponding Green's functions (GFs) within a layered, spherical, transversely isotropic and self-gravitating Earth. These solutions are based on the spherical system of vector functions (or the vector spherical harmonics) and the dual varia...

Models for postseismic transient displacements can be formulated using logarithmic and exponential decay formulas with single or multiple timescales. The logarithmic form is associated with rate and state friction theory and afterslip, while the exponential form is associated with bulk viscoelastic relaxation of coseismic stresses. It is now quite...

Megathrust earthquakes are responsible for some of the most devastating natural disasters1. To better understand the physical mechanisms of earthquake generation, subduction zones worldwide are continuously monitored with geophysical instrumentation. One key strategy is to install stations that record signals from Global Navigation Satellite System...

Coordinate time series are, by definition, trajectories, so the kinematic models that geodesists and geophysicists use to describe these time series are trajectory models. We describe various classes of trajectory models, and present a dozen case studies that illustrate the use of these models and also illuminate the diversity of ways in which the...

GNSS trajectory prediction modeling is necessary to obtain the time evolution of arbitrary points located between GNSS stations in a geodetic reference frame. If the GNSS-defined reference frame includes areas that experience coseismic deformation, its trajectory model needs to incorporate an estimate of the static deformation field generated by se...

We present an accurate approach for calculating the point-dislocation Green’s functions (GFs) for a layered, spherical, transversely-isotropic and self-gravitating Earth. The formalism is based on the approach recently used to find analytical solutions for the dislocation Love numbers (DLNs). However, in order to make use of the DLNs, we first anal...

Deformation associated with plate convergence at subduction zones is accommodated by a complex system involving fault slip and viscoelastic flow. These processes have proven difficult to disentangle. The 2010 Mw 8.8 Maule earthquake occurred close to the Chilean coast within a dense network of continuously recording Global Positioning System statio...

The GRACE mission has had a revolutionary impact on the study of Earth system processes, but it provides a band‐limited representation of mass changes. This is particularly problematic when studying mass changes that tend to be concentrated in fairly narrow zones near the edges of the Greenland Ice Sheet. In this study, coarse‐resolution estimates...

The elastic displacements caused by a point load imposed on the surface of a layered, spherical, and self‐gravitating Earth can be expressed in terms of infinite series of Legendre polynomials or their derivatives, multiplied by constants, called Love numbers, that depend on the summation index or degree. Truncating these infinite series causes osc...

In this paper, we derive analytical expressions for the dislocation Love numbers (DLNs) for a layered, spherical, transversely isotropic and self-gravitating Earth. This solution is based on the spherical system of vector functions (or the vector spherical harmonics) and a new propagating matrix method called the dual variable and position method....

Significance The recent deglaciation of Greenland is a response to both oceanic and atmospheric forcings. From 2000 to 2010, ice loss was concentrated in the southeast and northwest margins of the ice sheet, in large part due to the increasing discharge of marine-terminating outlet glaciers, emphasizing the importance of oceanic forcing. However, t...

The Global Positioning System (GPS) and Gravity Recovery and Climate Experiment (GRACE) provide important geodetic datasets to study glacial mass change. Applying the multichannel singular spectral analysis to the GPS-measured vertical and horizonal crustal displacement and GRACE-derived vertical displacement near Jakobshavn Isbræ (JI) in western G...

The recognition of transient motion in terrestrial continuous Global Positioning System (GPS) time series implies the knowledge of certain time functions that we assume to be ever present in the time series. By assuming that the permanent time functions are the long-term secular velocity of the Earth and the seasonal oscillations, we define the tot...

A quick rebound for Antarctic crust Earth's crust deforms under the load of glaciers and ice sheets. When these masses are removed, the crust rebounds at a time scale determined by the viscosity of the upper mantle. Using GPS, Barletta et al. found that the viscosity of the mantle under the West Antarctic Ice Sheet is much lower than expected. This...

Chile is one of the world’s most seismically active regions and is therefore extensively studied by the earthquake sciences. The great length of the country hosts a variety of measurement systems allowing for the characterization of earthquake processes over a wide range of timescales and in different phases of the seismic cycle. Starting in the ea...

Since its creation in 1998, the Argentine Continuous Satellite Monitoring Network (Red Argentina de Monitoreo Satelital Continuo [RAMSAC]) has grown to include more than 100 continuously operating Global Navigation Satellite Systems (GNSS) stations in Argentina. RAMSAC Receiver Independent Exchange Format (RINEX) data and their derived positioning...

Pan et al. presented a new analytical approach to compute the elastic load Love numbers (ELLNs) for an elastic, transversely isotropic, spherical, layered and self-gravitating Earth with a layered fluid core. Any layer or shell can be compressible or incompressible. Here, we enhance this formulation by replacing the direct propagator matrix with th...

Simple or multiple timescale transient models for postseismic transient displacements can be formulated using logarithmic and exponential decay formulas. The logarithmic form is associated with rate and state friction theory and afterslip, while the exponential form is associated with bulk viscoelastic relaxation of coseismic stresses. Many theoris...

We calculated surface displacements produced by a synthetic megathrust earthquake using two spherical, layered, elastic dislocation models which differ only in that one model accounts for the coupling between elasticity and gravity and the other does not. We show that including gravity perturbs the displacement field differently in the near-, mediu...

In response to present-day ice mass loss on and near the Greenland Ice Sheet, steady crustal uplifts have been observed from the network of Global Positioning System (GPS) stations mounted on bedrock. In addition to the secular uplift trends, the GPS time series also show prominent annual variability. Here we examine the annual changes of the verti...

Measurements of vertical crustal uplift from bedrock sites around the edge of the Greenland ice sheet (GrIS) can be used to constrain present day mass loss. Interpreting any observed crustal displacement around the GrIS in terms of present day changes in ice is complicated, however, by the glacial isostatic adjustment (GIA) signal. With GPS observa...

The Antarctic GPS Network (ANET) is recording in the Amundsen Embayment some of the fastest sustained bedrock uplift rates in the world. This can be largely explained by a short-time-scale GIA response of a low viscosity upper mantle to post- Little Ice Age ice mass changes. In this study we have observations from six GPS stations that can locally...

The postseismic deformation captured with continuous Global Positioning System (cGPS) monitoring following many recent mega-thrust events has been shown to be a signal composed of two dominant processes: afterslip on the plate interface and viscoelastic relaxation of the continental and oceanic mantles in response to the coseismic stress perturbati...

Accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice and ocean load changes occurring since the Last Gl...

This review provides updated estimates of the glacial isostatic adjustment (GIA) component of present-day uplift at a suite of Global Navigation Satellite System (GNSS) sites in Greenland using the most recently published global ice sheet deglaciation histories. For some areas of Greenland (e.g. the north-west and north-east), the use of GNSS to es...

A new GPS-derived surface velocity field for the central Andean backarc permits an assessment of orogenic wedge deformation across the southern Subandes of Bolivia, where recent studies suggest that great earthquakes (>Mw 8) are possible. We find that the backarc is not isolated from the main plate boundary seismic cycle. Rather, signals from subdu...

We review the theory of the Earth's elastic and gravitational response to a surface disk load. The solutions for displacement of the surface and the geoid are developed using expansions of Legendre polynomials, their derivatives and the load Love numbers. We provide a matlab function called Diskload that computes the solutions for both uncompensat...

We demonstrate a flexible strategy for local tsunami warning that relies on regional geodetic and seismic stations. Through retrospective analysis of four recent tsunamigenic events in Japan and Chile, we show that rapid earthquake source information, provided by methodologies developed for earthquake early warning, can be used to generate timely e...

The 2010, (Mw 8.8) Maule, Chile, earthquake produced large co-seismic displacements and non-secular, post-seismic deformation, within latitudes 28(Formula presented.)S–40(Formula presented.)S extending from the Pacific to the Atlantic oceans. Although these effects are easily resolvable by fitting geodetic extended trajectory models (ETM) to contin...

We present an analytical solution for the elastic deformation of an elastic, transversely isotropic, layered and self-gravitating Earth by surface loads. We first introduce the vector spherical harmonics to express the physical quantities in the layered Earth. This reduces the governing equations to a linear system of equations for the expansion co...

Least squares collocation (LSC) has been successfully applied to develop the Velocity Model for SIRGAS (VEMOS) (Drewes and Heidbach, 2012) used to predict the velocities in the Geocentric Reference System for the Americas (Sistema de Referencia Geocéntrico para las Américas, SIRGAS) GNSS reference frame. After the 2010 (Mw 8.8) Maule, Chile earthqu...

We identified co-seismic ionospheric disturbances (CID) in Antarctica generated by the 2010 Maule and the 2011 Tohoku-Oki earthquakes analyzing TEC data with a modified beamforming technique. Beamforming in Antarctica, however, is not straightforward due to the effects of array deformation and atmospheric neutral wave-ionospheric plasma coupling. W...

We describe an algorithm for rapidly computing the surface displacements induced by a general polygonal load on a layered, isotropic, elastic half-space. The arbitrary surface pressure field is discretized using a large number, n, of equally-sized circular loading elements. The problem is to compute the displacement at a large number, m, of points...

Several recent great earthquakes have produced regional to continental sized non-secular post-seismic deformation fields that are easily resolvable with GPS, requiring further development of geodetic reference frame velocities to include these effects. The 2010, (Mw 8.8) Maule, Chile, earthquake produced a measurable, non-secular, post-seismic sign...

The developing high-resolution chronostratigraphy of the Cambrian provides an updated age model for various geologic and biotic events that occurred during this critical period of Earth history. Broad, time-specific patterns of lithofacies, such as organic-rich deposits, and biofacies appear to be consistent across all Cambrian paleocontinents. Rec...

In a warming climate, surface meltwater production on large ice sheets is expected to increase. If this water is delivered to the ice sheet base it may have important consequences for ice dynamics. For example, basal water distributed in a diffuse network can decrease basal friction and accelerate ice flow, whereas channelized basal water can move...

Numerical 2-D models based on the principle of minimum work were used to examine the space-time distribution of active faulting during the evolution of orogenic wedges. A series of models focused on thin-skinned thrusting illustrates the effects of arid conditions (no erosion), unsteady state conditions (accretionary influx greater than erosional e...

The South Scotia Ridge Transform (SSRT) plate boundary between the Scotia and Antarctic plates experienced large strike-slip earthquakes on August 4, 2003 (Mw 7.6) and November 17, 2013 (Mw 7.8). These events have overlapping aftershock zones, which is unusual. A 36°–45° southward dipping fault zone ruptured with left-lateral displacements in each...

We focus on the relation between seismic and total postseismic afterslip following the Maule Mw 8.8 earthquake on 2010 February 27 in central Chile. First, we calculate the cumulative slip released by aftershock seismicity. We do this by summing up the aftershock regions and slip estimated from scaling relations. Comparing the cumulative seismic sl...

GPS total electron content (TEC) measurements are commonly used to study ionospheric disturbances in the near and far field. For co-seismic ionospheric disturbances (CIDs) the apparent velocity of the signal can be calculated from distance travel-time plots or interferometric stacking techniques. To date, signals related to solid earth-atmosphere c...

The Greenland ice sheet has been one of the largest contributors to global sea-level rise over the past 20 years, accounting for 0.5 mm yr−1 of a total of 3.2 mm yr−1. A significant portion of this contribution is associated with the speed-up of an increased number of glaciers in southeast and northwest Greenland. Here, we show that the northeast G...

1.0 Ice Sheet Wide Elevation Changes, 2.0 GPS data, 3.0 NEGIS regional analysis, 4.0 Climate data, 5.0 References.

We sketch the evolution of station trajectory models used in crustal motion geodesy over the last several decades, and describe some recent generalizations of these models that allow geodesists and geophysicists to parameterize accelerating patterns of displacement in general, and postseismic transient deformation in particular. Modern trajectory m...

[1] Observations of coseismic and postseismic deformation associated with the 2010 Mw = 8.8 Maule earthquake in south-central Chile provide constraints on the spatial heterogeneities of frictional properties on a major subduction megathrust and how they have influenced the seismic rupture and postseismic effects. We find that the bulk of coseismic...

We focus on the relation of aftershock seismicity and GPS-derived displacements following the Maule Mw 8.8 earthquake on 27 February 2010 in central Chile. The cumulative number of aftershocks and surface displacements follow a first order linear relationship indicating that both processes decay with a similar time dependent function. Based on this...

We analyze Global Positioning System (GPS) time series of relative vertical and horizontal surface displacements from 2006 to 2012 at four GPS sites located between ˜5 and ˜150 km from the front of Jakobshavn Isbræ (JI) in west Greenland. Horizontal displacements during 2006-2010 at KAGA, ILUL, and QEQE, relative to the site AASI, are directed towa...

We estimate the mass loss rate of Upernavik Isstrøm (UI) using surface elevation changes between a SPOT 5 Digital Elevation Model (DEM) from 2008 and NASA's Airborne Topographic Mapper (ATM) data from 2010. To assess the validity of our mass loss estimate, we analyze GPS data between 2007 and 2011 from two continuous receivers, UPVK and SRMP which...

The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in response to past and present-day changes in ice mass. Crustal displacement is largely accounted for by an annual oscillation superimposed on a sustai...

We examine the electromagnetic coupling of a GPS antenna–monument pair in terms of its simulated affect on long GPS coordinate time series. We focus on the Earth and Polar Observing System (POLENET) monument design widely deployed in Antarctica and Greenland in projects interested particularly in vertical velocities. We base our tests on an absolut...

To advance earthquake research, a unique LiDAR (Light Detection and Ranging) survey was conducted to map an approximately 1,000 km segment of the San Andreas Fault in southern California in the spring of 2005. The objective was to produce a surface model along the fault line at extremely high accuracy and consequently, extraordinary care was devote...

Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the Greenland ice sheet’s (GrIS) contribution to global sea-level rise. Here, we map elevation changes in northwest Greenland during 2003-2009 using high-resolution Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data (Zwally, 2010) supp...

The Maule earthquake of 27th February 2010 (Mw = 8.8) affected ~ 500 km of the Nazca-South America plate boundary in south-central Chile producing spectacular crustal deformation. Here, we present a detailed estimate of static coseismic surface offsets as measured by survey and continuous GPS, both in near- and far-field regions. Earthquake slip al...

We present a method for constructing and assessing the stability of a geometrical reference frame for use in vertical crustal motion studies. Our approach exploits the fact that when we transform GPS velocity solutions from one reference frame (RF) to another one using a Helmert transformation, only the frame translation rate parameters produce sig...

The Greenland GPS Network (GNET) uses GPS geodesy to measure the displacement of bedrock exposed near the margins of the Greenland Ice Sheet. The amplitudes of the observed vertical velocities indicate that over most of coastal Greenland these displacements are dominated by the solid earth's instantaneous elastic response to contemporary losses in...

The Antarctica component of the NSF supported POLENET GPS network is an autonomous, continuously recording GPS network that sends GPS phase data files on a daily basis via satellite to the UNAVCO Facility (UF) Archive. The data are openly available from the UF Archive upon receipt. We have developed a system for automatically processing the continu...

On 27 February 2010 the Mw 8.8 Maule earthquake in Central Chile ruptured a seismic gap where significant strain had accumulated since 1835. Shortly after the mainshock a dense network of temporary seismic landstations was installed along the whole rupture zone in order to capture the aftershock activity. We present the aftershock distribution and...

Observations of coseismic and postseismic deformation associated with large megathrust earthquakes probe the frictional properties and states of stress along a subduction interface. The 2010 Mw 8.8 Maule earthquake in south-central Chile, together with the 1835 Concepción earthquake and the 1960 Valdivia earthquake, provide key constraints on the d...

The potential for earthquakes greater than Mw 8 rupturing the decollement below Bolivia's Southern Subandes orogenic wedge has been recently recognized although great events are not documented in historical seismicity catalogs and paleoseismologic studies in this part of Bolivia are non-existent. Here, we present the first evidence for a recent sur...

Geologic records and geodetic measurements of glacial isostatic crustal motions are presented from the southern Victoria Land region of Antarctica. In much of the world, key records used for mapping and modeling glacial isostatic crustal motions come from raised paleoshorelines and beaches of ice-marginal lakes and seas. While such records are scar...

We report on the results of both campaign and continuous GPS measurements performed over the past 17 years in the area of the Southern and Northern Patagonian Ice Fields of Chile and Argentina. The network is composed of ~60 campaign sites and ~10 continuous sites that provide a relatively dense, 2-D sampling of the deformation field associated wit...

Of the 3 great earthquakes to have occurred in the GPS observational era, the proximity to Andes of the 2010 Maule event offers the most promise in relating subduction-zone forcing to active orogenic process. In particular, the backarc in this part of the Andes is unique because Quaternary fold and thrust belt shortening rates are almost negligible...

The great 27 February 2010 Mw 8.8 earthquake off the coast of southern Chile ruptured a ˜600 km length of subduction zone. In this paper, we make two independent estimates of shear stress in the crust in the region of the Chile earthquake. First, we use a coseismic slip model constrained by geodetic observations from interferometric synthetic apert...

Abstract Available from http://www.agu.org

Large earthquakes produce crustal deformation that can be quantified by geodetic measurements, allowing for the determination of the slip distribution on the fault. We used data from Global Positioning System (GPS) networks in Central Chile to infer the static deformation and the kinematics of the 2010 moment magnitude (M(w)) 8.8 Maule megathrust e...

Subduction of the Nazca plate beneath South America has driven the growth of the Andes Mountains. Subduction has routinely generated earthquakes larger than magnitude 8.0 along the western margin of the mountain belt, but the potential size of less frequent earthquakes in the eastern, backarc margin is unknown. Continued support of the high Andean...

Static offsets produced by the February 27, 2010 Mw = 8.8 Maule, Chile earthquake as measured by GPS and InSAR constrain coseismic slip along a section of the Andean megathrust of dimensions 650 km (in length) x 180 km (in width). GPS data have been collected from both campaign and continuous sites sampling both the near-field and far field. ALOS/P...

We use Global Positioning System (GPS) velocities and kinematic Finite Element models (FE-models) to infer the state of locking between the converging Nazca and South America plates in South–Central Chile (36°S−46°S) and to evaluate its spatial and temporal variability. GPS velocities provide information on earthquake-cycle deformation over the las...

Newly installed polar geodetic networks such as the Greenland GPS Network (GNET) and the Antarctic GPS Network (ANET) provide a means to determine the movement of the Earth's crust in response to past and present changes in ice mass. It is possible to distinguish between bedrock motions driven by glacial isostatic adjustment (GIA) - the response of...

Because the signal is so big, great earthquakes allow us to make quantum leaps in our understanding of Earth deformation process and material properties. The Maule earthquake, with its occurrence near a large subaerial landmass and the large numbers of instruments available to study it, will surely become one of the most important geophysical event...

The amount of continuous GPS (cGPS) stations deployed in southern South America (0°-54°S) was largely increased over the decade before the 27 February 2010 Maule earthquake to reach a total of 25 stations. 43 new cGPS have been installed after such event, near and around the ruptured area. This is by far the best geodetically-observed megathrust ea...

Radar interferometry from the ALOS satellite captured the coseismic ground deformation associated with the 2010 Mw 8.8 Maule, Chile earthquake. We processed the ALOS interferograms with our newly developed GMTSAR software. The ScanSAR to stripe mode and the ScanSAR to ScanSAR interferograms along the descending orbits are critical to recover a near...

The February 27, 2010 Mw 8.8 earthquake struck southern Chile on the primary fault that defines the interface where the Nazca Plate subducts below the South American continent. The earthquake ruptured an area approximately 400 km in the along strike direction and about 200 km in the down dip direction. The availability of extensive geodetic data fr...

The M8.8 Maule earthquake of 27 Feb. 2010 in Chile was the largest earthquake that ruptured a mature seismic gap in a subduction zone, monitored with a dense space-geodetic network. This provides an image of the pre-seismically locked state of the plate interface of unprecedented high resolution, allowing for an assessment of the spatial correlatio...

The wealth of GPS data recorded during and after the Maule earthquake allows us to test numerical models of co- and post-seismic deformation. We develop spherical-earth finite element models invoking bi-viscous viscoelastic stress relaxation and kinematically prescribed afterslip. For coseismic deformation, only elastic moduli are relevant: the You...

The southern Andes associated with the 2010 and 1960 megathrust earthquakes are characterized by a narrow cordillera, relatively low elevations ( 4000 m), large amounts of Neogene crustal shortening, and andesitic-dacitic stratovolcanoes and ignimbrite complexes that are restricted to the arc. Furthermore, in contrast to the currently active fold a...

The February 2010 Mw 8.8 Chile earthquake ruptured a 450 km-long portion of the Nazca-South America subduction zone. The southern part of this section last ruptured in the 1835 magnitude 8.5 Concepcion event and the northernmost part in the 1906 Mw 8.5 Valparaiso earthquake. The 2010 rupture was also adjacent to the northern extent of the Mw 9.5 ea...