Coseismic Deformation Field of the Mw 7.3 12 November 2017 Sarpol-e Zahab (Iran) Earthquake: A Decoupling Horizon in the Northern Zagros Mountains Inferred from InSAR Observations

Sanaz Vajedian; Mahdi Motagh; Zahra Mousavi; Khalil Motaghi; Eric. Fielding; Bahman Akbari; Hans-Ulrich Wetzel; Aliakbar Darabi

doi:10.3390/rs10101589

From coseismic offsets to fault-block mountains

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1711203114 ◽

2017 ◽

Vol 114 (37) ◽

pp. 9820-9825 ◽

Cited By ~ 5

Author(s):

George A. Thompson ◽

Tom Parsons

Keyword(s):

Upper Mantle ◽

Hanging Wall ◽

Large Earthquake ◽

Western United States ◽

Coseismic Deformation ◽

Finite Element Models ◽

Interferometric Synthetic Aperture Radar ◽

Normal Faulting ◽

Gravitational Forces ◽

Fault Block

In the Basin and Range extensional province of the western United States, coseismic offsets, under the influence of gravity, display predominantly subsidence of the basin side (fault hanging wall), with comparatively little or no uplift of the mountainside (fault footwall). A few decades later, geodetic measurements [GPS and interferometric synthetic aperture radar (InSAR)] show broad (∼100 km) aseismic uplift symmetrically spanning the fault zone. Finally, after millions of years and hundreds of fault offsets, the mountain blocks display large uplift and tilting over a breadth of only about 10 km. These sparse but robust observations pose a problem in that the coesismic uplifts of the footwall are small and inadequate to raise the mountain blocks. To address this paradox we develop finite-element models subjected to extensional and gravitational forces to study time-varying deformation associated with normal faulting. Stretching the model under gravity demonstrates that asymmetric slip via collapse of the hanging wall is a natural consequence of coseismic deformation. Focused flow in the upper mantle imposed by deformation of the lower crust localizes uplift, which is predicted to take place within one to two decades after each large earthquake. Thus, the best-preserved topographic signature of earthquakes is expected to occur early in the postseismic period.

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Seismogenic source model of the 2019 Mw 5.9 East-Azerbaijan earthquake (NW Iran) through Sentinel-1 DInSAR measurements

10.5194/egusphere-egu2020-20404 ◽

2020 ◽

Author(s):

Emanuela Valerio ◽

Francesco Casu ◽

Vincenzo Convertito ◽

Claudio De Luca ◽

Vincenzo De Novellis ◽

...

Keyword(s):

Seismic Hazard ◽

Seismic Source ◽

Source Model ◽

Fault Model ◽

Strike Slip ◽

Coseismic Deformation ◽

Lateral Strike Slip ◽

Nw Iran ◽

Seismogenic Source ◽

East Azerbaijan

On 7 November 2019 (22:47 UTC) a Mw 5.9 earthquake struck the East-Azerbaijan region, in the north-western Iran, about 100 km east of Tabriz, the fourth largest city of Iran with a population of over two million. This seismic event caused both widespread damage to the surrounding villages and casualties, killing about 5 people and injuring hundreds. The occurrence of this earthquake is related to the main geodynamic regime controlled by the oblique Arabia-Eurasia convergence and, in particular, this event is inserted in the tectonic context of the East-Azerbaijan Plateau, a complex mountain belt that contains internal major fold-and-thrust belts.In this work, we first generate the coseismic deformation maps by applying the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique to SAR data collected along ascending and descending orbits by the Sentinel-1 constellation of the European Copernicus Programme. Then, we invert them through analytical modeling in order to better constrain the geometry and characteristics of the main source. The retrieved fault model revealed a shallow seismic source approximately NE&#8211;SW-striking and characterized by a left-lateral strike-slip, southeast-dipping faulting mechanism. Our retrieved solution reveals a new minor fault never mapped in geological maps before, whose kinematics is compatible with that of the surrounding structures and with the local and regional stress states.&#160;Moreover, we also use the preferred fault model to calculate the Coulomb Failure Function at the nearby receiver faults; taking into account the surrounding geological structures reported in literature, we show that all the considered receiver faults have been positively stressed by the main event. This is also confirmed by the distribution of the aftershocks that occurred near the considered faults.&#160;The analysis of the earthquake nucleated along these left-lateral strike-slip minor fault is essential to improve our knowledge of the East-Azerbaijan Plateau; therefore, further studies are required to evaluate their role in seismic hazard definition of northwest of Iran, in order to help in the mitigation of the seismic hazard in seismogenic regions unprepared for the occurrence of seismic events.This work is supported by: the 2019-2021 IREA-CNR and Italian Civil Protection Department agreement, H2020 EPOS-SP (GA 871121), ENVRI-FAIR (GA 824068) projects, and the I-AMICA (PONa3_00363) project.

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Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

10.21203/rs.3.rs-25613/v2 ◽

2020 ◽

Author(s):

Pengfei Yu ◽

Xuejun Qiao ◽

Wei Xiong ◽

Wei Chen ◽

Zhaosheng Nie ◽

...

Keyword(s):

European Space Agency ◽

Source Model ◽

Descent Method ◽

Steepest Descent Method ◽

Coseismic Deformation ◽

Seismogenic Fault ◽

Coulomb Stress Changes ◽

Rupture Area ◽

Space Agency ◽

Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and -4.2 cm for the ascending interferogram and are 7.2 cm and -3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5 ~ 7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688×1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

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Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

10.21203/rs.3.rs-25613/v3 ◽

2020 ◽

Author(s):

Pengfei Yu ◽

Xuejun Qiao ◽

Wei Xiong ◽

Wei Chen ◽

Zhaosheng Nie ◽

...

Keyword(s):

European Space Agency ◽

Source Model ◽

Descent Method ◽

Steepest Descent Method ◽

Coseismic Deformation ◽

Seismogenic Fault ◽

Coulomb Stress Changes ◽

Rupture Area ◽

Space Agency ◽

Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and -4.2 cm for the ascending interferogram and are 7.2 cm and -3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5 ~ 7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688×1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

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Impact of Down‐Dip Rupture Limit and High‐Stress Drop Subevents on Coseismic Land‐Level Change during Cascadia Megathrust Earthquakes

Bulletin of the Seismological Society of America ◽

10.1785/0120190043 ◽

2019 ◽

Vol 109 (6) ◽

pp. 2187-2197 ◽

Cited By ~ 1

Author(s):

Erin A. Wirth ◽

Arthur D. Frankel

Keyword(s):

Seismic Hazard ◽

Seismic Velocity ◽

High Stress ◽

Strong Motion ◽

Velocity Model ◽

Source Model ◽

Coseismic Deformation ◽

Earthquake Scenarios ◽

Megathrust Earthquakes ◽

Level Change

Abstract Seismic hazard associated with Cascadia megathrust earthquakes is strongly dependent on the landward rupture extent and heterogeneous fault properties. We use 3D numerical simulations and a seismic velocity model for Cascadia to estimate coseismic deformation due to M 9–9.2 earthquake scenarios. Our earthquake source model is based on observations of the 2010 M 8.8 Maule and 2011 M 9.0 Tohoku earthquakes, which exhibited distinct strong motion‐generating subevents in the deep portion of the fault. We compare our estimates for land‐level change to paleoseismic estimates for coseismic coastal subsidence during the A.D. 1700 Cascadia earthquake. Results show that megathrust rupture extending to the 1 cm/yr locking contour provides a good match to geologic data. In addition, along‐strike variations in coastal subsidence can be matched by including low slip, strong motion‐generating subevents in the down‐dip region of the megathrust. This work demonstrates the potential to improve seismic hazard estimates for Cascadia earthquakes by comparing physics‐based earthquake simulations with geologic observations.

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Development of a Late Quaternary Marine Terraced Landscape during On-Going Tectonic Contraction, Crescent City Coastal Plain, California

Quaternary Research ◽

10.1006/qres.1999.2061 ◽

1999 ◽

Vol 52 (2) ◽

pp. 217-228 ◽

Cited By ~ 11

Author(s):

Michael Polenz ◽

Harvey M. Kelsey

Keyword(s):

Coastal Plain ◽

Late Quaternary ◽

Hanging Wall ◽

Thrust Fault ◽

Cascadia Subduction Zone ◽

Marine Terrace ◽

Crescent City ◽

The North ◽

Marine Terraces ◽

Tectonically Active

The Crescent City coastal plain is a low-lying surface of negligible relief that lies on the upper plate of the Cascadia subduction zone in northernmost California. Whereas coastal reaches to the north in southern Oregon and to the south near Cape Mendocino contain flights of deformed marine terraces from which a neotectonic history can be deduced, equivalent terraces on the Crescent City coastal plain are not as pronounced. Reexamination of the coastal plain revealed three late Pleistocene marine terraces, identified on the basis of subtle geomorphic boundaries and further delineated by differentiable degrees of soil development. The youngest marine terrace is preserved in the axial valley of a broad syncline, and the two older marine terraces face each other across the axial region. An active thrust fault, previously recognized offshore, underlies the coastal plain, and folding in the hanging wall of this thrust fault has dictated, through differential uplift, the depositional limits of each successive marine terrace unit. This study demonstrates the importance of local structures in coastal landscape evolution along tectonically active coastlines and exemplifies the utility of soil relative-age determinations to identify actively growing folds in landscapes of low relief.

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Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

Earth Planets and Space ◽

10.1186/s40623-020-01300-4 ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Pengfei Yu ◽

Xuejun Qiao ◽

Wei Xiong ◽

Wei Chen ◽

Zhaosheng Nie ◽

...

Keyword(s):

European Space Agency ◽

Source Model ◽

Descent Method ◽

Steepest Descent Method ◽

Coseismic Deformation ◽

Seismogenic Fault ◽

Coulomb Stress Changes ◽

Rupture Area ◽

Space Agency ◽

Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and − 4.2 cm for the ascending interferogram and are 7.2 cm and − 3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5–7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688 × 1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

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The epicentral fingerprint of earthquakes

10.5194/egusphere-egu21-2938 ◽

2021 ◽

Author(s):

Patrizio Petricca ◽

Christian Bignami ◽

Carlo Doglioni

Keyword(s):

Seismic Waves ◽

Hanging Wall ◽

Vertical Displacement ◽

Strike Slip ◽

Coseismic Deformation ◽

Far Field ◽

Ground Acceleration ◽

Epicentral Area ◽

Local Site ◽

Field Area

InSAR images allow to detect the coseismic deformation, delimiting the epicentral area where the larger displacement has been concentrated. The main observations are: 1) the most deformed area in the ideal case is elliptical (for dip-slip faults) or quadrilobated (for strike-slip faults) and coincides with the surface projection of the volume coseismically mobilized in the hanging wall of thrusts and normal faults, or the crustal walls adjacent to strike-slip faults; 2) the dimension of the deformed area detected by InSAR scales with magnitude of earthquake and for M&#8805;6 is always larger than 100 km, increasing to more than 550 km2 for M&#8776;6.5; 3) the seismic epicenter rarely coincide with the area of larger vertical shaking (either downward or upward); 4) the higher macroseismic intensity corresponds to the area of larger vertical displacement, apart from local site amplification effects; 5) outside this area, the vertical displacement is drastically lower, determining the strong attenuation of seismic waves and the decrease of the peak ground acceleration in the surrounding far field area, apart from local site amplifications; 6) the segment of the activated fault constrains the area where the vertical oscillations have been larger, allowing the contemporaneous maximum freedom degree of the crustal volume affected by horizontal maximum shaking, i.e., the near field or epicentral area; 7) therefore, the epicentral area and volume are active, i.e., they coseismically move and are contemporaneously crossed by seismic waves (active volume), whereas the surrounding far field area is mainly fixed and passively crossed by seismic waves (passive volume). Therefore, here we show how the InSAR images of areas affected by earthquakes represent the fingerprint of the epicentral area where the largest shaking has taken place during an earthquake. Seismic hazard assessments should rely on those data.

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COSEISMIC DISPLACEMENT ANALYSIS OF THE 12 NOVEMBER 2017 MW 7.3 SARPOL-E ZAHAB (IRAN) EARTHQUAKE FROM SAR INTERFEROMETRY, BURST OVERLAP INTERFEROMETRY AND OFFSET TRACKING

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-3-205-2018 ◽

2018 ◽

Vol IV-3 ◽

pp. 205-209 ◽

Cited By ~ 1

Author(s):

Sanaz Vajedian ◽

Mahdi Motagh

Keyword(s):

Sar Interferometry ◽

Double Difference ◽

Coseismic Deformation ◽

Main Mode ◽

Angle Diversity ◽

Heading Direction ◽

Progressive Scan ◽

Offset Tracking ◽

Along Track ◽

Azimuth Resolution

Interferometric wide-swath mode of Sentinel-1, which is implemented by Terrain Observation by Progressive Scan (TOPS) technique, is the main mode of SAR data acquisition in this mission. It aims at global monitoring of large areas with enhanced revisit frequency of 6 days at the expense of reduced azimuth resolution, compared to classical ScanSAR mode. TOPS technique is equipped by steering the beam from backward to forward along the heading direction for each burst, in addition to the steering along the range direction, which is the only sweeping direction in standard ScanSAR mode. This leads to difficulty in measuring along-track displacement by applying the conventional method of multi-aperture interferometry (MAI), which exploits a double difference interferometry to estimate azimuth offset. There is a possibility to solve this issue by a technique called “Burst Overlap Interferometry” which focuses on the region of burst overlap. Taking advantage of large squint angle diversity of ~1° in burst overlapped area leads to improve the accuracy of ground motion measurement especially in along-track direction. We investigate the advantage of SAR Interferometry (InSAR), burst overlap interferometry and offset tracking to investigate coseismic deformation and coseismic-induced landslide related to 12 November 2017 Mw 7.3 Sarpol-e Zahab earthquake in Iran.

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