Postseismic Surface Deformation Research Articles

Time series analysis of the pre-seismic and post-seismic surface deformation of the 2017 Iran–Iraq earthquake derived from Sentinel-1 InSAR data

Time series analysis of the pre-seismic and post-seismic surface deformation of the 2017 Iran–Iraq earthquake derived from Sentinel-1 InSAR data

The 27 September 2021 Earthquake in Central Crete (Greece)—Detailed Analysis of the Earthquake Sequence and Indications for Contemporary Arc-Parallel Extension to the Hellenic Arc

The Arkalochori village in central Crete was hit by a large earthquake (Mw = 6.0) on 27 September 2021, causing casualties, injuries, and severe damage to the infrastructure. Due to the absence of apparent surface rupture and the initial focal mechanism solution of the seismic event, we initiated complementary, multi-disciplinary research by combining seismological and remote sensing data processing, followed by extensive field validation. Detailed geological mapping, fault surface measuring accompanied with tectonic analysis, fault photorealistic model creation by unmanned aerial system data processing, post-seismic surface deformation analysis by DInSAR image interpretation coupled with accurately relocated epicenters recorded by locally established seismographs have been carried out. The combination of the results obtained from these techniques led to the determination of the contemporary tectonic stress regime that caused the earthquake in central Crete, which was found compatible with extensional processes parallel to the Hellenic arc.

Coseismic and Early Postseismic Slip Models of the 2021 Mw 7.4 Maduo Earthquake (Western China) Estimated by Space‐Based Geodetic Data

AbstractThe May 22nd, 2021,7.4 Maduo earthquake occurred on an intraplate fault of Bayan‐Har block in the Tibet Plateau. Here, we derive the coseismic and early postseismic surface deformations from the Sentinel‐1 (S1) interferometric synthetic aperture radar (InSAR) data. We use the subpixel offsets of SAR and Sentinel‐2 (S2) optical images to determine the surface rupture traces. The fault geometry and coseismic fault slip distribution of multi‐segmented ruptures are estimated by inverting InSAR interferograms and SAR pixel offsets. We show that at least five fault segments with curved geometry are activated, with a peak coseismic slip of about 5 m. The geodetic data inversion suggests that an NW‐striking blind segment near the Eling Lake may have ruptured during the 2021 event. Postseismic slip inversion with the 60‐day cumulative line‐of‐sight deformations, shows that the early afterslip of 0.1 ∼ 0.3 m occurred mostly toward the downdip direction of the main coseismic slip asperities. The afterslip geodetic moment accounts for approximately 15.3% of the coseismic one. Coulomb stress analysis shows that the nucleation of the Maduo earthquake is partially facilitated by the 1947 M7.7 Dari earthquake.

Long-lived afterslip of the 2013Mw 6.1 Minab earthquake detected by Persistent Scatterer Interferometry along the Irer fault (western Makran-Zagros transition zone, Iran)

SUMMARYThe ratio of seismogenic to aseismic deformation along active faults is needed to estimate their seismogenic potential and hazards. Seismologic and geodetic methods routinely capture coseismic displacements, but data acquisition requirements to fully document post-seismic deformation are not well known. Our study documents afterslip between about 18 months and 4 years after a mid-size earthquake and, based on remote structural mapping, we document fault rupture segments not previously associated with that earthquake. Persistent scatterer interferometric analysis of Sentinel-1A aperture radar data acquired between October 2014 and December 2018 reveals prolonged post-seismic deformation following the 11 May 2013 Mw 6.1 Minab earthquake and its aftershocks. The surface deformation data yield a sharp contrast across both the main seismogenic fault (here named the Irer fault) and its northeastern splay, and it is compatible with left-lateral motion along both faults. The PSI data helped us to identify and map the splay fault in the satellite imagery. We could then measure the geological offset along both faults, finding maximum displacements of about 1 km (main fault) and 350 m (splay). Our modelling of the observed post-seismic surface deformation pattern shows that post-seismic deformation was accommodated by left-lateral afterslip, not viscoelastic relaxation. This result is consistent with previous propositions that Mw 6 earthquakes do not measurably excite deeply seated viscoelastic relaxation mechanisms. Our afterslip modelling yields a slip pattern from the surface to a depth of 6 km to maximum 16 km, in agreement with the depth of the coseismic slip-distribution, and a maximum displacement of ∼7 cm along the fault, but located ∼8 km to the east of the coseismic slip maximum. Moment release during the observed afterslip in our study is Mw 5.7, or 12% of the coseismic moment released by main shock and aftershocks together. Combined with previously published results for the early post-seismic period (first 2 months), we estimate the aseismic moment to be at least ∼37% of the total, implying a high ratio of aseismic to seismic moment release for the Irer fault. Our results show that observation time windows well beyond 5 years are needed to record afterslip following mid-sized earthquakes. Thus, progress in understanding the transition from post-seismic to interseismic fault behaviour critically depends on the availability of data provided by satellite missions such as Copernicus Sentinel-1A. Similarly, robust comparison of the post-seismic rates with long-term geological rates requires palaeoseismic study and dating of related morphotectonic features.

Resolving the Kinematics and Moment Release of Early Afterslip Within the First Hours Following the 2016 Mw 7.1 Kumamoto Earthquake: Implications for the Shallow Slip Deficit and Frictional Behavior of Aseismic Creep

AbstractAs stresses following rupture are dissipated continuous measurements of postseismic surface deformation provide insight into variations of the frictional strength of faults and the rheology of the lower crust and upper mantle. Due to the difficulty of capturing the earliest phase of afterslip, most analyses have focused on understanding postseismic processes over timescales of weeks to years. Here we investigate the kinematics, moment release, and frictional properties of the earliest phase of afterslip within the first hours following the 2016 Mw 7.1 Kumamoto earthquake using a network of 5‐minute sampled continuous Global Positioning System (GPS) stations. Using independent component analysis to filter the GPS data, we find that (1) early afterslip contributes only ~1% of total moment release within the first hour and 8% after 24 hr. This suggests that the lack of a coseismic slip deficit, which we estimate using standard geodetic data sets (e.g., InSAR, GPS, and pixel offsets) and which span the first 4 days of the postseismic period, is largely reflective of the dynamic rupture process and we can rule out contamination of moment release by early afterslip. (2) Early afterslip shows no evidence of a delayed nucleation or acceleration phase, where instead fault patches transition to immediate deceleration following rupture that is consistent with frictional relaxation under steady state conditions with dependence only on the sliding velocity. (3) There is a close correlation between the near‐field aftershocks and afterslip within the first hours following rupture, suggesting afterslip may still be an important possible triggering mechanism during the earliest postseismic period.

Orthogonal Fault Rupture and Rapid Postseismic Deformation Following 2019 Ridgecrest, California, Earthquake Sequence Revealed From Geodetic Observations

AbstractWe studied the 2019 Mw6.4 and Mw7.1 Ridgecrest, California, earthquake sequence, using Sentinel‐1 and ALOS‐2 coseismic interferograms and subpixel offsets to retrieve the three‐dimensional (3‐D) surface displacements. By inverting the 3‐D displacements, optimal dip angles of the earthquake faults and the slip model were obtained. The interferometric synthetic aperture radar‐based slip model supplemented with the analysis of GPS data shows that the Mw6.4 event ruptured two orthogonal faults and its major geodetic moment was released by sinistral motion on a NE‐SW trending fault that dips 78° NW. Right‐lateral slip on NW‐SE trending subvertical faults was responsible for the Mw7.1 earthquake. Postseismic analysis with U.S. Geological Survey earthquake catalog and GPS time series at site P595 shows that the postseismic surface deformation following the Mw7.1 event has similar temporal patterns with the postseismic moment release, but requires more energy. This implies that the early aftershocks were likely controlled by rapid afterslip following the mainshock.

Co- and Early Postseismic Deformation Due to the 2019 Ridgecrest Earthquake Sequence Constrained by Sentinel-1 and COSMO-SkyMed SAR Data

Abstract The 2019 Ridgecrest earthquake sequence ruptured a series of conjugate faults in the broad eastern California shear zone, north of the Mojave Desert in southern California. The average spacing between Global Navigation Satellite System (GNSS) stations around the earthquakes is 20–30 km, insufficient to constrain the rupture details of the earthquakes. Here, we use Sentinel-1 and COSMO-SkyMed (CSK) Synthetic Aperture Radar data to derive the high-resolution coseismic and early postseismic surface deformation related to the Ridgecrest earthquake sequence. Line of sight (LoS) Interferometric Synthetic Aperture Radar displacements derived from both Sentinel-1 and CSK data are in good agreement with GNSS measurements. The maximum coseismic displacement occurs near the Mw 7.1 epicenter, with an estimated fault offset of ∼4.5 m on a northwest-striking rupture. Pixel tracking analysis of CSK data also reveals a sharp surface offset of ∼1 m on a second northwest-striking fault strand on which the Mw 6.4 foreshock likely nucleated, which is located ∼2–3 km east of the major rupture. The lack of clear surface displacement across this fault segment during the Mw 6.4 event suggests this fault might have ruptured twice, with more pronounced and shallow slip during the Mw 7.1 mainshock. Both Sentinel-1 and CSK data reveal clear postseismic deformation following the 2019 Ridgecrest earthquake sequence. Cumulative postseismic deformation near the Mw 7.1 epicenter ∼2 months after the mainshock reaches ∼5 cm along the satellites’ LoSs. The observed postseismic deformation near the fault is indicative of both afterslip and poroelastic rebound. We provide data derived in this study in various data formats, which will be useful for the broad community studying this earthquake sequence.

GPS measurements on pre-, co- and post-seismic surface deformation at first multi-parametric geophysical observatory, Ghuttu in Garhwal Himalaya, India

Abstract We investigate the surface deformation pattern of GPS station at MPGO Ghuttu (GHUT) to find out the cause of anomalous behavior in the continuous GPS time series. Seven years (2007-2013) of GPS data has been analyzed using GAMIT/GLOBK software and generated the daily position time series. The horizontal translational motion at GHUT is 43.7 ± 1 mm/yr at an angle of 41°± 3° towards NE, while for the IGS station at LHAZ, the motion is 49.4 ±1 mm/yr at 18 ± 2.5° towards NEE. The estimated velocity at GHUT station with respect to IISC is 12 ± 1 mm/yr towards SW. Besides, we have also examined anomalous changes in the time series of GHUT before, after and during the occurrences of local earthquakes by considering the empirical strain radius; such that, a possible relationship between the strain radius and the occurrences of earthquakes have been explored. We considered seven local earthquakes on the basis of Dobrovolsky strain radius condition having magnitude from 4.5 to 5.7, which occurred from 2007 to 2011. Results show irrespective of the station strain radius, pre-seismic surface deformational anomalies are observed roughly 70 to 80 days before the occurrence of a Moderate or higher magnitude events. This has been observed for the cases of those events originated from the Uttarakashi and the Chamoli seismic zones in the Garhwal and Kumaun Himalaya. Occurrences of short (< 100 days) and long (two years) inter-seismic events in the Garhwal region plausibly regulating and diffusing the regional strain accumulation.

Stress transfer, aftershocks distribution and InSAR analysis of the 2005 Dahuieh earthquake, SE Iran

In this paper, the authors studied the 2005 Dahuieh Zarand earthquake in SE Iran by combining Coulomb stress changes, InSAR study, locally recorded aftershocks and their spatial correlations, co-seismic slip distributions, Iso-seismal curves, and strong ground motion data. The event (MW 6.4) occurred in Kerman province, SE Iran, on February 22, 2005. The locally recorded aftershocks were used to calculate the Coulomb stress changes and the decay time based on Omori's law. The decay time of aftershocks calculated by Omori's law was about 500 days. A great correlation was particularly deduced from the spatial distribution of the aftershocks and areas of increased Coulomb stress for optimal strike slip faults. Moreover, using SAR Interferograms, we determined the postseismic surface deformations. Also, the majority of the coseismic slips occurred in the eastern part, where there was sparsely distributed aftershocks. The deformation maps showed active uplift for at least 300 days after the main shock. We reconciled time decays of the aftershocks with the postseismic uplifts, calculated from InSAR. In our model, which is based on after slip evolution, for one of the postseismic relaxation mechanisms, we found a proper correlation between the aftershock decay time and InSAR displacement maps to define postseismic motions. There is also a reasonable correspondence between the mainshock intensity, the acceleration map, and postseismic ground uplift, estimated by InSAR.

Modeling the poroelastic response to megathrust earthquakes: A look at the 2012 M 7.6 Costa Rican event

Abstract We model the subsurface hydrologic response to the 7.6 Mw subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on September 5, 2012. The regional-scale poroelastic model of the overlying plate integrates seismologic, geodetic and hydrologic data sets to predict the post-seismic poroelastic response. A representative two-dimensional model shows that thrust earthquakes with a slip width less than a third of their depth produce complex multi-lobed pressure perturbations in the shallow subsurface. This leads to multiple poroelastic relaxation timescales that may overlap with the longer viscoelastic timescales. In the three-dimensional model, the complex slip distribution of 2012 Nicoya event and its small width to depth ratio lead to a pore pressure distribution comprising multiple trench parallel ridges of high and low pressure. This leads to complex groundwater flow patterns, non-monotonic variations in predicted well water levels, and poroelastic relaxation on multiple time scales. The model also predicts significant tectonically driven submarine groundwater discharge off-shore. In the weeks following the earthquake, the predicted net submarine groundwater discharge in the study area increases, creating a 100 fold increase in net discharge relative to topography-driven flow over the first 30 days. Our model suggests the hydrological response on land is more complex than typically acknowledged in tectonic studies. This may complicate the interpretation of transient post-seismic surface deformations. Combined tectonic-hydrological observation networks have the potential to reduce such ambiguities.

INVESTIGATION OF LITHOSPHERIC STRUCTURE IN MONGOLIA: INSIGHTS FROM INSAR OBSERVATIONS AND MODELLING

Abstract. The western Mongolia is a seismically active intracontinental region, with ongoing tectonic deformation and widespread seismicity related to the far-field effects of India-Eurasia collision. During the 20th century, four earthquakes with the magnitude larger than 8 occurred in the western Mongolia and its surrounding regions, providing a unique opportunity to study the geodynamics of intracontinental tectonic deformations. The 1957 magnitude 8.3 Gobi-Altai earthquake is one of the largest seismic events. The deformation pattern of rupture zone associated with this earthquake is complex, involving left-lateral strike-slip and reverse dip-slip faulting on several distinct geological structures in a 264 × 40 km wide zone. To understand the relationship between the observed postseismic surface deformation and the rheological structure of the upper lithosphere, Interferometric Synthetic Aperture Radar (InSAR) data are used to study the 1957 earthquake. Then we developed a postseismic model in a spherical, radially layered elastic-viscoelastic Earth based on InSAR results, and further analysed the dominant contribution to the surface deformation. This work is important for understanding not only the regional tectonics, but also the structure and dynamics of the lithosphere. SAR data were acquired from the ERS1/2 and Envisat from 1996 to 2010. Using the Repeat Orbit Interferometry Package (ROI_PAC), 124 postseismic interferograms are produced on four adjacent tracks. By stacking these interferograms, the maximum InSAR line-of-sight deformation rate along the Gobi-Altai fault zone is obtained. The main results are as follows: (1) The maximum InSAR line-of-sight deformation velocity along this large fault zone is about 6 mm/yr; (2) The modelled surface deformation suggests that the viscoelastic relaxation is the most reasonable mechanism to explain the observed surface motion; (3) The optimal model cover the Gobi-Altai seismogenic thickness is 10 km; (4) The lower bound of Maxwell viscosity of lower crust and upper mantle is approximately 9 × 1019 Pa s, and the Maxwell relaxation time corresponding to this viscosity is 95.13 years.

Omori‐like decay of postseismic velocities following continental earthquakes

AbstractVarious mechanisms have been proposed to explain the transient, enhanced surface deformation rates following earthquakes. Unfortunately, these different mechanisms can produce very similar surface deformation patterns leading to difficulty in distinguishing between them. Here we return to the observations themselves and compile near‐field postseismic velocity measurements following moderate to large continental earthquakes. We find that these velocities have a remarkably consistent pattern, with velocity inversely proportional to time since the earthquake. This suggests that postseismic velocities show an Omori‐like decay and that postseismic displacements increase logarithmically over time. These observations are inconsistent with simple, linear Maxwell or Burgers body viscoelastic relaxation mechanisms but are consistent with rate‐and‐state frictional afterslip models and power law shear zone models. The results imply that near‐field postseismic surface deformation measurements are primarily the result of fault zone processes and, therefore, that the inference of lower crustal viscosities from near‐field postseismic deformation requires care.

Separating rapid relocking, afterslip, and viscoelastic relaxation: An application of the postseismic straightening method to the Maule 2010 cGPS

AbstractThe postseismic deformation captured with continuous Global Positioning System (cGPS) monitoring following many recent megathrust 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 perturbation. Following the south central Chile 2010 Maule Mw 8.8 earthquake, the time series from the regional cGPS network show a distinct curvature in the pathway of the horizontal motion that is not easily fit by a stationary decaying pattern of afterslip in combination with viscoelastic relaxation. Here we show that with realistic assumptions about the long‐term decay of the afterslip signal, the postseismic signal can be decomposed into three first‐order contributing processes: plate interface relocking, plate interface afterslip, and mantle viscoelastic relaxation. From our analyses we conclude that the plate interface recovers its interseismic locking state rapidly (model space ranges between an instant recovery and a period of 1 year), a finding that supports laboratory experimental evidence as well as some recent studies of aftershocks and postseismic surface deformation. Furthermore, relocking is the main cause of the curvature in the cGPS signal, and this study presents a plausible range of geodetic relocking rates following a megathrust earthquake.

Surface displacements of the 2014 Cephalonia (Greece) earthquake using high resolution SAR interferometry

The island of Cephalonia (Western Greece), was struck by two strong seismic events, with magnitudes Mw = 6.0 and Mw = 5.9 which occurred on Jan. 26, 2014 and Feb. 3, 2014 respectively. The first event was located near Argostoli’s village, whereas the second one was located at the north part of Livadi village. These two strong seismic events were followed by smaller aftershocks provoking extensive crustal movements and structural damage effects. Differential Synthetic Aperture Radar Interferometry (DInSAR) is a powerful remote sensing tool for ground motion monitoring. Since the last two decades, DInSAR is widely used in a variety of applications including natural hazards such as earthquakes. In 2007, a high resolution X-band satellite namely TerraSAR-X was launched. Due to its short revisit cycle of 11 days and its short wavelength, it has a good potential to capture faster surface movements. This study refers to the application of the DInSAR using TerraSAR-X strip map data to monitor the co- and post-seismic surface deformation caused by the second seismic event. Using DInSAR methodology, three differential interferograms were calculated showing the displacement trend of the region, before and after the earthquake. Results demonstrate that the main part of the island shows stability to low uplift whereas in the western part a significant deformation pattern is observed. The findings permit a better understanding and identification of the local tectonic setting of the study area and the investigation of the reasons that some settlements were strongly affected by this seismic activity.

Co- and post-seismic surface deformation and gravity changes of MS7.0 Lushan, earthquake

On April 20, 2013, an earthquake with magnitude 7.0 occurred in the southwest of the Longmenshan fault system in and around Lushan County, Sichuan Province, China. This devastating earthquake killed hundreds of people, injured 10 thousand others, and collapsed countless buildings. In order to analyze the potential risk of this big earthquake, we calculate the co- and post-seismic surface deformation and gravity changes of this event. In this work, a multilayered crustal model is designed, and the elastic dislocation theory is utilized to calculate the co- and post-seismic deformations and gravity changes. During the process, a rupture model obtained by seismic waveform inversion (Liu et al. Sci China Earth Sci 56(7):1187–1192, 2013) is applied. The time-dependent relaxation results show that the influences on Lushan and its surrounding areas caused by the MS7.0 Lushan earthquake will last as long as 10 years. The maximum horizontal displacement, vertical uplift, and settlement are about 5 cm, 21.24 cm, and 0.16 m, respectively; the maximal positive and negative values of gravity changes are 45 and −0.47 μGal, respectively. These results may be applied to evaluate the long-term potential risk caused by this earthquake and to provide necessary information for post-earthquake reconstruction.

Seven years of postseismic deformation following the 2003 Mw = 6.8 Zemmouri earthquake (Algeria) from InSAR time series

We study the postseismic surface deformation of the Mw 6.8, 2003 Zemmouri earthquake (northern Algeria) using the Multi‐Temporal Small Baseline InSAR technique. InSAR time series obtained from 31 Envisat ASAR images from 2003 to 2010 reveal sub‐cm coastline ground movements between Cap Matifou and Dellys. Two regions display subsidence at a maximum rate of 2 mm/yr in Cap Djenet and 3.5 mm/yr in Boumerdes. These regions correlate well with areas of maximum coseismic uplifts, and their association with two rupture segments. Inverse modeling suggest that subsidence in the areas of high coseismic uplift can be explained by afterslip on shallow sections (<5 km) of the fault above the areas of coseismic slip, in agreement with previous GPS observations. The earthquake impact on soft sediments and the ground water table southwest of the earthquake area, characterizes ground deformation of non‐tectonic origin. The cumulative postseismic moment due to 7 years afterslip is equivalent to an Mw 6.3 earthquake. Therefore, the postseismic deformation and stress buildup has significant implications on the earthquake cycle models and recurrence intervals of large earthquakes in the Algiers area.

Comment on “Surface deformation caused by April 6th 2009 earthquake in L’Aquila (Italy): A comparative analysis from ENVISAT ASAR, ALOS PALSAR and ASTER” by M.A. Goudarzi, T. Woldai, V.A. Tolpekin

The present work concerns some observations about the paper by Goudarzi et al. (2011), related to the surface deformation analysis carried out for the earthquake that hit the city of L’Aquila, Italy, on April 2009 and based on SAR Differential Interferometry (DInSAR) technique.We have manly identified a criticality about the post-seismic deformation, named by the author postseismic relaxation. The analysis performed by Goudarzi et al. (2011) leads to misleading conclusions in terms of seismic hazard all over the epicentral region. Here, some considerations driven by literature and interferograms comparison demonstrate the incorrectness of their interpretation concerning the coseismic and post seismic surface deformation.

Modeling of co- and post-seismic surface deformation and gravity changes of MW6.9 Yushu, Qinghai, earthquake

Based on the elastic dislocation theory, multilayered crustal model, and rupture model obtained by seismic waveform inversion, we calculated the co- and post-seismic surface deformation and gravity changes caused by the Yushu MW6.9 earthquake occurred on April 14, 2010. The observed GPS velocity field and gravity field in Yushu areas are disturbed by the co- and post-seismic effects induced by Yushu earthquake, thus the theoretical co- and post-seismic deformation and gravity changes will provide important modification for the background tectonic movement of Yushu and surrounding regions. The time relaxation results show that the influences of Yushu earthquake on Yushu and surrounding areas will last as long as 30 to 50 years. The maximum horizontal displacement, vertical uplift and settlement are about 1.96, 0.27 and 0.16 m, respectively, the maximal positive and negative value of gravity changes are 8.892×10−7 m·s−2 and −4.861×10−7 m·s−2, respectively. Significant spatial variations can be found on the co- and post-seismic effects: The co-seismic effect mainly concentrates in the region near the rupture fault, while viscoelastic relaxation mostly acts on the far field. Therefore, when using the geodetic data to research tectonic motion, we should not only consider the effect of co-seismic caused by earthquake, but also pay attention to the effect of viscoelastic relaxation.

Energetic rupture, coseismic and post-seismic response of the 2008 MW 6.4 Achaia-Elia Earthquake in northwestern Peloponnese, Greece: an indicator of an immature transform fault zone

SUMMARY The 2008 June 8, moment magnitude MW 6.4 crustal earthquake in northwestern Peloponnese, Greece, was a strong-shaking dextral strike-slip event with teleseismic broad-band and high-frequency energy magnitudes Me of 6.8 and 7.2, respectively. A high stress drop 5–10 times the global average is associated with excessive high-frequency energy. The NE–SW trending fault plane shown by the aftershock distribution and focal mechanism is not associated with previously mapped faults, and no obvious coseismic surface rupture was discovered. Contrasting the enhanced rupture energy, the event created no substantial coseismic or post-seismic surface deformation, likely due to a fault buried below a detached thick and compositionally weak flysch layer. Comparative spatial analysis including over 30 regional strike-slip events between 1965 and 2009 reveals a NE–SW striking diffuse transform fault zone subparallel to the Cephalonia Transform Fault. The dextral sense of motion along the transform zone is consistent with the ongoing Global Positioning System (GPS)-derived deformation along the West Hellenic Arc and the motion on the Cephalonia Transform Fault. Characterizing this system is important to constraining the seismic hazard near Patras, a major port city immediately NE of the 2008 event.

Post-seismic Surface Deformation Following the 2008 Iwate-Miyagi Nairiku Earthquake Detected by ALOS/PALSAR

Post-seismic Surface Deformation Following the 2008 Iwate-Miyagi Nairiku Earthquake Detected by ALOS/PALSAR