Co‐ and Post‐Seismic Mechanisms of the 2020 Mw 6.3 Yutian Earthquake and Local Stress Evolution

The Mw 6.3 Yutian earthquake, occurred in northwestern Tibet on 25 June 2020, is one of the major events sequentially occurring in the region following the 2008 Mw 7.2, 2012 Mw 6.2, and 2014 Mw 6.9 earthquakes, and is of great significance for studying the tectonic activity and assessing future seismic hazards in the region. In this study, we used Sentinel‐1 Synthetic Aperture Radar images to retrieve co‐ and post‐seismic deformation and to investigate the coseismic rupture behavior of the fault and the mechanisms of postseismic deformation. Based on the slip models of recent four nearby major earthquakes, we explored the local stress evolution, triggering mechanism of the 2020 event and future regional seismic hazards. Postseismic modeling reveals that afterslip on fault patches surrounding the ruptured co‐seismic patches is the main mechanism responsible for the near‐field deformation, with the poroelastic rebound relaxation only accounts for maximumly 25% of the ground displacement and limited impact on the overall deformation pattern. The Coulomb failure stress changes (ΔCFS) suggest that the 2020 Yutian earthquake was inhibited by the 2008 Mw 7.2 earthquake but facilitated by the 2012 Mw 6.2 and 2014 Mw 6.9 earthquakes, resulting in an overall ΔCFS with a large lateral gradient on the 2020 fault. Stress concentrations on nearby major faults indicate increasing chances of seismic hazards in the eastern section of the Altyn Tagh fault at 82.8°E, the western section of the Guozha Co fault at 81.5°E and the entire section of the Ashikule fault.

[1]  Qiang Chen,et al.  The 2021 Mw7.4 Maduo Earthquake: Coseismic Slip Model, Triggering Effect of Historical Earthquakes and Implications for Adjacent Fault Rupture Potential , 2022, Journal of Geodynamics.

[2]  Caijun Xu,et al.  The July 2020 Mw 6.3 Nima Earthquake, Central Tibet: A Shallow Normal-Faulting Event Rupturing in a Stepover Zone , 2021, Seismological Research Letters.

[3]  K. Tan,et al.  Slip Model of the 2020 Yutian (Northwestern Tibetan Plateau) Earthquake Derived From Joint Inversion of InSAR and Teleseismic Data , 2021, Earth and Space Science.

[4]  J. Zhuang,et al.  Stress Transfer Along the Western Boundary of the Bayan Har Block on the Tibet Plateau From the 2008 to 2020 Yutian Earthquake Sequence in China , 2021, Geophysical Research Letters.

[5]  Zhenhong Li,et al.  Triggered afterslip on the southern Hikurangi subduction interface following the 2016 Kaikōura earthquake from InSAR time series with atmospheric corrections , 2020 .

[6]  Bin Zhao,et al.  Normal Faulting Movement During the 2020 Mw 6.4 Yutian Earthquake: A Shallow Rupture in NW Tibet Revealed by Geodetic Measurements , 2020, Pure and Applied Geophysics.

[7]  J. Liu‐Zeng,et al.  Detailed mapping of the surface rupture of the 12 February 2014 Yutian Ms7.3 earthquake, Altyn Tagh fault, Xinjiang, China , 2020, Science China Earth Sciences.

[8]  Wenbin Xu,et al.  Source Model of the 2014 Mw 6.9 Yutian Earthquake at the Southwestern End of the Altyn Tagh Fault in Tibet Estimated from Satellite Images , 2020 .

[9]  Caijun Xu,et al.  Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E-W Thinning in Northern Tibet , 2020, Remote. Sens..

[10]  S. Toda,et al.  Long- and Short-Term Stress Interaction of the 2019 Ridgecrest Sequence and Coulomb-Based Earthquake Forecasts , 2020, Bulletin of the Seismological Society of America.

[11]  Y. Fialko,et al.  Finite Slip Models of the 2019 Ridgecrest Earthquake Sequence Constrained by Space Geodetic Data and Aftershock Locations , 2020 .

[12]  Milan Lazecký,et al.  LiCSBAS: An Open-Source InSAR Time Series Analysis Package Integrated with the LiCSAR Automated Sentinel-1 InSAR Processor , 2020, Remote. Sens..

[13]  Walter H. F. Smith,et al.  The Generic Mapping Tools Version 6 , 2019, Geochemistry, Geophysics, Geosystems.

[14]  Wenbin Xu,et al.  Changes in Groundwater Level Possibly Encourage Shallow Earthquakes in Central Australia: The 2016 Petermann Ranges Earthquake , 2019, Geophysical Research Letters.

[15]  Zhenhong Li,et al.  Generic Atmospheric Correction Model for Interferometric Synthetic Aperture Radar Observations , 2018, Journal of Geophysical Research: Solid Earth.

[16]  William D. Barnhart,et al.  Ramp-flat basement structures of the Zagros Mountains inferred from co-seismic slip and afterslip of the 2017 Mw7.3 Darbandikhan, Iran/Iraq earthquake , 2018, Earth and Planetary Science Letters.

[17]  Wanpeng Feng,et al.  Geodetic Constraints of the 2017 Mw7.3 Sarpol Zahab, Iran Earthquake, and Its Implications on the Structure and Mechanics of the Northwest Zagros Thrust‐Fold Belt , 2018, Geophysical Research Letters.

[18]  Jiajun Chen,et al.  Small Magnitude Co-Seismic Deformation of the 2017 Mw 6.4 Nyingchi Earthquake Revealed by InSAR Measurements with Atmospheric Correction , 2018, Remote. Sens..

[19]  Antonio Pepe,et al.  Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data , 2017 .

[20]  Zhenhong Li,et al.  Generation of real‐time mode high‐resolution water vapor fields from GPS observations , 2017 .

[21]  R. Bürgmann,et al.  Stress‐driven relaxation of heterogeneous upper mantle and time‐dependent afterslip following the 2011 Tohoku earthquake , 2016 .

[22]  Shuxin Yang,et al.  Coseismic Coulomb stress changes caused by the Mw6.9 Yutian earthquake in 2014 and its correlation to the 2008 Mw7.2 Yutian earthquake , 2015 .

[23]  C. Werner,et al.  Sentinel-1 support in the GAMMA Software , 2015 .

[24]  Kenneth W. Hudnut,et al.  Fault‐Slip Distribution of the 1999 Mw 7.1 Hector Mine Earthquake, California, Estimated from Postearthquake Airborne LiDAR Data , 2015 .

[25]  I. Ryder,et al.  Recent seismic and aseismic activity in the Ashikule stepover zone, NW Tibet , 2014 .

[26]  Du Peng,et al.  Seismic Activities and Earthquake Potential in the Tibetan Plateau , 2014 .

[27]  Haluk Ozener,et al.  Postseismic deformation following the Mw 7.2, 23 October 2011 Van earthquake (Turkey): Evidence for aseismic fault reactivation , 2014 .

[28]  Wanpeng Feng,et al.  The 2011 MW 6.8 Burma earthquake: fault constraints provided by multiple SAR techniques , 2013 .

[29]  Kate Huihsuan Chen,et al.  The role of a hidden fault in stress triggering: Stress interactions within the 1935 Mw 7.1 Hsinchu-Taichung earthquake sequence in central Taiwan , 2013 .

[30]  Xi-wei Xu,et al.  Normal- and oblique-slip of the 2008 Yutian earthquake: Evidence for eastward block motion, northern Tibetan Plateau , 2013 .

[31]  P. Segall,et al.  Challenging the rate‐state asperity model: Afterslip following the 2011 M9 Tohoku‐oki, Japan, earthquake , 2012 .

[32]  Caijun Xu,et al.  Postseismic motion after the 2001 MW 7.8 Kokoxili earthquake in Tibet observed by InSAR time series , 2012 .

[33]  T. Yasuda,et al.  Yutian normal faulting earthquake ( Mw 7 . 1 ) , NW Tibet : Non-planar fault modeling and implications for the Karakax Fault , 2011 .

[34]  James Jackson,et al.  The 2010 MW 6.8 Yushu (Qinghai, China) earthquake: Constraints provided by InSAR and body wave seismology , 2011 .

[35]  Zhenhong Li,et al.  Extension on the Tibetan plateau: recent normal faulting measured by InSAR and body wave seismology , 2010 .

[36]  Anthony Sladen,et al.  Seismic and aseismic slip on the Central Peru megathrust , 2010, Nature.

[37]  Zhenhong Li,et al.  Integration of InSAR Time-Series Analysis and Water-Vapor Correction for Mapping Postseismic Motion After the 2003 Bam (Iran) Earthquake , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[38]  C. Marone,et al.  Potential for earthquake triggering from transient deformations , 2008 .

[39]  Kristine M. Larson,et al.  Coseismic and early postseismic slip for the 2003 Tokachi‐oki earthquake sequence inferred from GPS data , 2008 .

[40]  Peizhen Zhang,et al.  Present‐day crustal motion within the Tibetan Plateau inferred from GPS measurements , 2007 .

[41]  H. Zebker,et al.  Persistent scatterer interferometric synthetic aperture radar for crustal deformation analysis, with application to Volcán Alcedo, Galápagos , 2007 .

[42]  A. Freed,et al.  Afterslip (and only afterslip) following the 2004 Parkfield, California, earthquake , 2007 .

[43]  James Jackson,et al.  Surface displacements and source parameters of the 2003 Bam (Iran) earthquake from Envisat advanced synthetic aperture radar imagery , 2005 .

[44]  Serkan B. Bozkurt,et al.  Forecasting the evolution of seismicity in southern California : Animations built on earthquake stress transfer : Stress transfer, earthquake triggering, and time-dependent seismic hazard , 2005 .

[45]  T. Wright,et al.  Surface displacements and source parameters of the 2003 Bam (Iran) earthquake from Envisat ASAR imagery , 2004 .

[46]  Roland Bürgmann,et al.  Evidence of power-law flow in the Mojave desert mantle , 2004, Nature.

[47]  T. Wright,et al.  InSAR Observations of Low Slip Rates on the Major Faults of Western Tibet , 2004, Science.

[48]  Y. Fialko.  Probing the mechanical properties of seismically active crust with space geodesy: Study of the coseismic deformation due to the 1992 Mw7.3 Landers (southern California) earthquake , 2004 .

[49]  Paul Segall,et al.  Space time distribution of afterslip following the 2003 Tokachi‐oki earthquake: Implications for variations in fault zone frictional properties , 2004 .

[50]  Jian Lin,et al.  Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearby thrust and strike-slip faults , 2004 .

[51]  Masayuki Kikuchi,et al.  Co‐seismic slip, post‐seismic slip, and largest aftershock associated with the 1994 Sanriku‐haruka‐oki, Japan, earthquake , 2003 .

[52]  Zhong Lu,et al.  Source model for the Mw 6.7, 23 October 2002, Nenana Mountain Earthquake (Alaska) from InSAR , 2003 .

[53]  Paul Segall,et al.  Post-earthquake ground movements correlated to pore-pressure transients , 2003, Nature.

[54]  John E. Vidale,et al.  Damage to the shallow Landers fault from the nearby Hector Mine earthquake , 2003, Nature.

[55]  Bernard Minster,et al.  Deformation on Nearby Faults Induced by the 1999 Hector Mine Earthquake , 2002, Science.

[56]  H. Zebker,et al.  Fault Slip Distribution of the 1999 Mw 7.1 Hector Mine, California, Earthquake, Estimated from Satellite Radar and GPS Measurements , 2002 .

[57]  Bertrand Meyer,et al.  Oblique Stepwise Rise and Growth of the Tibet Plateau , 2001, Science.

[58]  Thomas A. Hennig,et al.  The Shuttle Radar Topography Mission , 2001, Digital Earth Moving.

[59]  C. W. Chen,et al.  Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms. , 2000, Journal of the Optical Society of America. A, Optics, image science, and vision.

[60]  R. Stein.  The role of stress transfer in earthquake occurrence , 1999, Nature.

[61]  F. Rocca,et al.  Permanent scatterers in SAR interferometry , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[62]  Kenneth W. Hudnut,et al.  Poroelastic rebound along the Landers 1992 earthquake surface rupture , 1998 .

[63]  C. Werner,et al.  Radar interferogram filtering for geophysical applications , 1998 .

[64]  Ruth A. Harris,et al.  Introduction to Special Section: Stress Triggers, Stress Shadows, and Implications for Seismic Hazard , 1998 .

[65]  P. Rosen,et al.  Atmospheric effects in interferometric synthetic aperture radar surface deformation and topographic maps , 1997 .

[66]  N. Beeler,et al.  Transient triggering of near and distant earthquakes , 1997, Bulletin of the Seismological Society of America.

[67]  D. Wells,et al.  New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement , 1994, Bulletin of the Seismological Society of America.

[68]  Y. Okada.  Internal deformation due to shear and tensile faults in a half-space , 1992, Bulletin of the Seismological Society of America.

[69]  Chris Marone,et al.  On the mechanics of earthquake afterslip , 1991 .

[70]  Philip England,et al.  Extension during continental convergence, with application to the Tibetan Plateau , 1989 .

[71]  R. Armijo,et al.  Quaternary extension in southern Tibet: Field observations and tectonic implications , 1986 .

[72]  P. Molnar,et al.  Active tectonics of Tibet , 1978 .

[73]  Peter Molnar,et al.  Active faulting and tectonics in China , 1977 .

[74]  Zhenhong Li,et al.  Interferometric synthetic aperture radar atmospheric correction using a GPS-based iterative tropospheric decomposition model , 2018 .

[75]  W. Yong.  The mechanical effects of the 2008 M_s7.3 Yutian,Xinjiang earthquake on the neighboring faults and its tectonic origin of normal faulting mechanism , 2010 .

[76]  James Jackson,et al.  The 1994 Sefidabeh (eastern Iran) earthquakes revisited: new evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault , 2006 .

[77]  S. Acinas,et al.  Evidence of power-law flow in the Mojave desert mantle , 2004 .