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

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.

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

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.

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

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.

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

2020 ◽  
Author(s):  
Pengfei Yu ◽  
Xuejun Qiao ◽  
Wei Xiong ◽  
Wei Chen ◽  
Zhaosheng Nie ◽  
...  
Keyword(s):  
Transition Zone ◽  
Strong Earthquake ◽  
Earthquake Swarm ◽  
European Space Agency ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Western China ◽  
Coseismic Deformation ◽  
Coulomb Stress Changes ◽  
Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Western China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Many strong earthquakes occurred in this region, such as the 1997 Jiashi strong earthquake swarm. In this study, Interferometric Synthetic Aperture Radar (InSAR) was used to obtain the coseismic deformation field from the ascending and descending Sentinel-1A satellite data of the European Space Agency. The results showed that the coseismic deformation was distributed along the Kalpingtag fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The long axis of the deformation was near the east-west direction. The maximum and minimal displacements along the line of sight (LOS) were 5.3 cm, 7.2 cm and -4.2 cm, -3 cm for the ascending and descending interferograms, respectively. The slip model inverted by the steepest descent method demonstrated that the rupture process of this earthquake is dominated by a thrust fault. The slips were concentrated in a depth of 3.5 ~ 6.5 km. The maximum slip was 0.29 m. The estimated total seismic moment was 1.728×1018 Nm, corresponding to a magnitude of Mw 6.09. The inversion revealed that the coseismic rupture was located at the transition zone between the shallow high-dip fault and the deep detachment fault. The geometry of the coseismic rupture is direct evidence of the deep attitude of the Kalping fault, indicating the possibility of independent earthquakes at the shallow ramp-to-flat transition zone of an orogenic belt. 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 another strong earthquake in this region in the future.

scholarly journals Source Model and Stress Disturbance of the 2017 Jiuzhaigou Mw 6.5 Earthquake Constrained by InSAR and GPS Measurements

2018 ◽  
Vol 10 (9) ◽  
pp. 1400 ◽  
Author(s):  
Shunying Hong ◽  
Xin Zhou ◽  
Kui Zhang ◽  
Guojie Meng ◽  
Yanfang Dong ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Source Model ◽  
Descent Method ◽  
Slip Distribution ◽  
Steepest Descent Method ◽  
Nonlinear Inversion ◽  
Fault Geometry ◽  
Seismogenic Fault ◽  
Jiuzhaigou Earthquake ◽  
Geometry Model

Seismogenic fault geometry, especially for a blind fault, is usually difficult to derive, based only on the distribution of aftershocks and interference fringes of Interferometric Synthetic Aperture Radar (InSAR). To better constrain the fault geometry of the 2017 Jiuzhaigou Mw 6.5 earthquake, we first carried out a nonlinear inversion for a single fault source using multi-peak particle swarm optimization (MPSO), Monte Carlo (MC), and Markov Chain Monte Carlo (MCMC) algorithms, respectively, with constraints of InSAR data in multiple SAR viewing geometries. The fault geometry models retrieved with different methods were highly consistent and mutually verifiable, showing that a blind faulting with a strike of ~154° and a dip angle of ~77° was responsible for the Jiuzhaigou earthquake. Based on the optimal fault geometry model, the fault slip distribution jointly inverted from the InSAR and Global Positioning System (GPS) data by the steepest descent method (SDM) and the MC method showed that the slip was mainly concentrated at the depth of 1–15 km, and only one slip center appeared at the depth of 5–9 km with a maximum slip of about 1.06 m, some different from previous studies. Taking the shear modulus of μ = 32 GPa, the seismic moment derived from the distributed slip model was about 7.85 × 1018 Nm, equivalent to Mw 6.54, which was slightly larger than that from the focal mechanism solutions. The fault spatial geometry and slip distribution could be further validated with the spatial patterns of the immediate aftershocks. Most of the off-fault aftershocks with the magnitude > M2 within one year after the mainshock occurred in the stress positive stress change area, which coincided with the stress triggering theory. The static Coulomb stress, triggered by the mainshock, significantly increased at the Tazang fault (northwest to the epicenter), and at the hidden North Huya fault, and partial segments of the Minjiang fault (west of the epicenter).

Multifault complex rupture and afterslip associated with the 2018 Mw 6.4 Hualien earthquake in northeastern Taiwan

2020 ◽  
Vol 224 (1) ◽  
pp. 416-434
Author(s):  
Dezheng Zhao ◽  
Chunyan Qu ◽  
Xinjian Shan ◽  
Roland Bürgmann ◽  
Wenyu Gong ◽  
...  
Keyword(s):  
Main Shock ◽  
Near Field ◽  
Active Faults ◽  
Fault Model ◽  
Body Waves ◽  
Coseismic Deformation ◽  
Coseismic Slip ◽  
Coulomb Stress Changes ◽  
Seismic Displacement ◽  
Stress Changes

SUMMARY We investigate the coseismic and post-seismic deformation due to the 6 February 2018 Mw 6.4 Hualien earthquake to gain improved insights into the fault geometries and complex regional tectonics in this structural transition zone. We generate coseismic deformation fields using ascending and descending Sentinel-1A/B InSAR data and GPS data. Analysis of the aftershocks and InSAR measurements reveal complex multifault rupture during this event. We compare two fault model joint inversions of SAR, GPS and teleseismic body waves data to illuminate the involved seismogenic faults, coseismic slip distributions and rupture processes. Our preferred fault model suggests that both well-known active faults, the dominantly left-lateral Milun and Lingding faults, and previously unrecognized oblique-reverse west-dipping and north-dipping detachment faults, ruptured during this event. The maximum slip of ∼1.6 m occurred on the Milun fault at a depth of ∼2–5 km. We compute post-seismic displacement time series using the persistent scatterer method. The post-seismic range-change fields reveal large surface displacements mainly in the near-field of the Milun fault. Kinematic inversions constrained by cumulative InSAR displacements along two tracks indicate that the afterslip occurred on the Milun and Lingding faults and the west-dipping fault just to the east. The maximum cumulative afterslip of 0.4–0.6 m occurred along the Milun fault within ∼7 months of the main shock. The main shock-induced static Coulomb stress changes may have played an important role in driving the afterslip adjacent to coseismic high-slip zones on the Milun, Lingding and west-dipping faults.

scholarly journals Coseismic Deformation and Speculative Seismogenic Fault of the 2017 MS 6.6 Jinghe Earthquake, China, Derived From Sentinel-1 Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Feng ◽  
Zechao Bai ◽  
Jinwei Ren ◽  
Shuaitang Huang ◽  
Lin Zhu
Keyword(s):  
European Space Agency ◽  
Image Data ◽  
Junggar Basin ◽  
Deformation Field ◽  
Slip Distribution ◽  
Coseismic Deformation ◽  
Dislocation Model ◽  
Seismogenic Fault ◽  
Geological Investigation ◽  
Maximum Deformation

A MS 6.6 earthquake struck Jinghe County in Bortala Mongol Autonomous Prefecture of Xinjiang Uygur Autonomous Region on August 9, 2017. The earthquake occurred near the eastern part of the Kusongmuxieke Piedmont Fault (KPF) in the southwest of Junggar Basin. Using two pairs of coseismic SAR image data from the ascending and descending tracks from Sentinel-1 (European Space Agency), we processed the interferograms to obtain the coseismic deformation field. We calculate the fault slip distribution of the earthquake based on the elastic half-space rectangular dislocation model with the available location, geometry from seismic data and the coseismic deformation data. The results show that the earthquake deformation field has the typical characteristics of thrust faulting. The uplift deformation field is about 28 km long and 20 km wide. The maximum displacements of InSAR line-of-sight to the ascending and descending tracks are 49 and 68 mm, respectively. The main slip is concentrated at the depth of 10–20 km. The inverted seismic moment is equivalent to a moment magnitude MW 6.3. This result is very similar to the slip distribution from the seismological inversion. The maximum deformation area and the distribution of aftershocks are both on the west side of the mainshock. They mutually confirm the characteristics of a unilateral rupture. According to stress triggering theory, the aftershocks within 1 month after the mainshock in the layer 10–14 km deep may have been triggered by the mainshock, and the transferred stress increases the seismic risk of the eastern section of the KPF fault. After more than 1 year, a MS 5.4 earthquake occurred to the southwest of the MS 6.6 Jinghe earthquake. Beacause the stress drop change (<0.01 MPa) is too small for the MS 5.4 earthquake to have been directly triggered. Based on the analysis of multisource data and the detailed geological investigation, the thrust Jinghenan fault which north of Kusongmuxieke Piedmont fault is inferred to be the seismogenic fault of the MS 6.6 Jinghe earthquake.

scholarly journals The Source Characteristics of the Mw6.4, 2016 Meinong Taiwan Earthquake from Teleseismic Data Using the Hybrid Homomorphic Deconvolution Method

2022 ◽  
Vol 12 (1) ◽  
pp. 494
Author(s):  
Boi-Yee Liao ◽  
Huey-Chu Huang ◽  
Sen Xie
Keyword(s):  
Total Duration ◽  
Large Earthquake ◽  
Radar Data ◽  
Source Model ◽  
Rupture Process ◽  
Vertical Deformation ◽  
Deconvolution Method ◽  
Synthetic Aperture Radar Data ◽  
Coulomb Stress Changes ◽  
Stress Changes

The kinematic source rupture process of the 2016 Meinong earthquake (Mw = 6.4) in Taiwan was derived from apparent source time functions retrieved from teleseismic S-waves by using a refined homomorphic deconvolution method. The total duration of the rupture process was approximately 15 s, and one slip-concentrated area can be represented as the source model based on images representing static slip distribution. The rupture process began in a down-dip direction from the fault toward Tainan City, strongly suggesting that the rupture had a unilateral northwestern direction. The asperity with an area of approximately 15 × 15 km2 and the maximum slip of approximately 2 m were centered 12.8 km northwest of the hypocenter. Coseismic vertical deformation was calculated based on the source model. Compared with the results derived from InSAR (Interferometric Synthetic Aperture Radar) data, our results demonstrated that the location with maximum uplift was accurately well detected, but our maximum value was just approximately 0.4 times of the InSAR-derived value. It reveals that there are the other mechanisms to affect the vertical deformation, rather than only depending on the source model. At different depths, areas west, east, and north of the hypocenter maintained high values of Coulomb stress changes. This explains the mechanism behind aftershocks being triggered and provides a reference for predicting aftershock locations after a large earthquake. The estimated seismic spectral intensities, including spectral acceleration and velocity intensity (SIa and SIv), were derived. Source directivity effects caused damage to buildings, and we concluded that all damaged buildings were located within a SIa value of 400 gal. Destroyed buildings taller than seven floors were located in an area with a SIv value of 30 cm/s. These observations agree with those on damages caused by the 2010 Jiasian earthquake (ML 6.4) in Tainan, Taiwan.

Preliminary Report on the 18 May 2020 Ms 5.0 Qiaojia Earthquake, Yunnan, China

2021 ◽  
Author(s):  
Zhen Fu ◽  
Changsheng Jiang ◽  
Fengling Yin ◽  
Lei Zhang ◽  
Xuanye Shen ◽  
...  
Keyword(s):  
Stress Field ◽  
Focal Mechanism ◽  
Negative Impact ◽  
Earthquake Hazard ◽  
Focal Mechanisms ◽  
Seismogenic Fault ◽  
Coulomb Stress Changes ◽  
Ludian Earthquake ◽  
Moderate Earthquake ◽  
Stress Changes

Abstract The 18 May 2020 Ms 5.0 Qiaojia earthquake occurred in Qiaojia County, Yunnan Province, ∼25  km away from the 3 August 2014 Ms 6.5 Ludian earthquake. This earthquake was well recorded by dense local seismic stations of the Qiaojia array constructed near the Xiaojiang fault zone. The focal mechanism of the mainshock exhibited strike-slip motion with a centroid depth of 8 km. We determined the seismogenic fault of the Qiaojia earthquake using aftershock relocation with local dense seismic arrays. The mainshock is located on a previously unmapped fault. Aftershocks clearly delineated east–west rupture plane, which was not revealed by the regional seismic network due to relatively sparse stations. The length and width of the aftershock zone are ∼5  km and 3 km, respectively. The focal mechanisms of 70 aftershocks with magnitudes ML≥1.0 showed similar focal mechanism with the mainshock. The stress field inverted from focal mechanisms of the aftershocks is consistent with the tectonic stress field. The coseismic and postseismic static coulomb stress changes show that the Ludian earthquake has a negative impact on the Qiaojia earthquake with a value of −0.01  MPa, implying that the Qiaojia earthquake was unlikely statically triggered by the Ludian earthquake. The Qiaojia earthquake sequence was characterized by low b-value and low-decay rate in the aftershock area, indicating high-seismic risk in this region. The dense seismic observation allows us to study the moderate earthquake in detail and provides us with valuable information of near-fault seismicity to analyze earthquake hazard and the potential of large earthquakes in the future.

scholarly journals Joint Inversion of GPS, Leveling, and InSAR Data for The 2013 Lushan (China) Earthquake and Its Seismic Hazard Implications

2020 ◽  
Vol 12 (4) ◽  
pp. 715 ◽  
Author(s):  
Zhicai Li ◽  
Yangmao Wen ◽  
Peng Zhang ◽  
Yang Liu ◽  
Yong Zhang
Keyword(s):  
Joint Inversion ◽  
Source Parameters ◽  
Estimation Method ◽  
Lushan Earthquake ◽  
Coseismic Deformation ◽  
Seismogenic Fault ◽  
Finite Fault ◽  
Stress Changes ◽  
Gps Leveling ◽  
2013 Lushan Earthquake

On 20 April 2013, a moment magnitude (Mw) 6.6 earthquake occurred in the Lushan region of southwestern China and caused more than 190 fatalities. In this study, we use geodetic data from nearly 30 continuously operating global positioning system (GPS) stations, two periods of leveling data, and interferometric synthetic aperture radar (InSAR) observations to image the coseismic deformation of the Lushan earthquake. By using the Helmert variance component estimation method, a joint inversion is performed to estimate source parameters by using these GPS, leveling, and InSAR data sets. The results indicate that the 2013 Lushan earthquake occurred on a blind thrust fault. The event was dominated by thrust faulting with a minor left-lateral strike–slip component. The dip angle of the seismogenic fault was approximately 45.0°, and the fault strike was 208°, which is similar to the strike of the southern Longmenshan fault. Our finite fault model reveals that the peak slip of 0.71 m occurred at a depth of ~12 km, with substantial slip at depths of 6–20 km. The estimated magnitude was approximately Mw 6.6, consistent with seismological results. Furthermore, the calculated static Coulomb stress changes indicate that the 2013 Lushan earthquake may have been statically triggered by the 2008 Wenchuan earthquake.

scholarly journals Rupture Kinematics and Coseismic Slip Model of the 2021 Mw 7.3 Maduo (China) Earthquake: Implications for the Seismic Hazard of the Kunlun Fault

2021 ◽  
Vol 13 (16) ◽  
pp. 3327
Author(s):  
Han Chen ◽  
Chunyan Qu ◽  
Dezheng Zhao ◽  
Chao Ma ◽  
Xinjian Shan
Keyword(s):  
Three Dimensional ◽  
Surface Displacement ◽  
Horizontal Displacement ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Coseismic Deformation ◽  
Slip Model ◽  
Displacement Fields ◽  
Coseismic Slip ◽  
The North

The 21 May 2021 Maduo earthquake was the largest event to occur on a secondary fault in the interior of the active Bayanhar block on the north-central Tibetan plateau in the last twenty years. A detailed kinematic study of the Maduo earthquake helps us to better understand the seismogenic environments of the secondary faults within the block, and its relationship with the block-bounding faults. In this study, firstly, SAR images are used to obtain the coseismic deformation fields. Secondly, we use a strain model-based method and steepest descent method (SDM) to resolve the three-dimensional displacement components and to invert the coseismic slip distribution constrained by coseismic displacement fields, respectively. The three-dimensional displacement fields reveal a dominant left-lateral strike-slip motion, local horizontal displacement variations and widely distributed near-fault subsidence/uplift deformation. We prefer a five-segment fault slip model, with well constrained fault geometry featuring different dip angles and striking, constrained by InSAR observations. The peak coseismic slip is estimated to be ~5 m near longitude 98.9°E at a depth of ~4–7 km. Overall, the distribution of the coseismic slip on the fault is highly correlated to the measured surface displacement offsets along the entire rupture. We observe the moderate shallow slip deficit and limited afterslip deformation following the Maduo earthquake, it may indicate the effects of off-fault deformation during the earthquake and stable interseismic creep on the fault. The occurrence of the Maduo earthquake on a subsidiary fault updates the importance and the traditional estimate of the seismic hazards for the Kunlun fault.

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