GPS and InSAR Inversion for Coseismic Deformation Field and Slip Distribution of the Ms7.0 Jiuzhaigou Earthquake

Author(s):  
Huixia Li ◽  
Wenhao Wu ◽  
Hang Guo ◽  
Richard B. Langley
2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Feng ◽  
Zechao Bai ◽  
Jinwei Ren ◽  
Shuaitang Huang ◽  
Lin Zhu

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.


2020 ◽  
Author(s):  
Xiongwei Tang ◽  
Rumeng Guo ◽  
Jianqiao Xu ◽  
Heping Sun ◽  
Xiaodong Chen ◽  
...  

Abstract On 8 August 2017, an Ms 7.0 earthquake occurred on a buried fault extending to the north of the Huya fault. Based on the coseismic deformation field obtained from Interferometric Synthetic Aperture Radar (InSAR) data and a series of finite fault model tests, we proposed a brand new two-fault model composed of a main fault and a secondary fault as the optimal model for the Jiuzhaigou earthquake, in which the secondary fault is at a large obtuse angle to the northern end of the main fault plane. Results show that the slip distribution is dominated by sinistral slip, with a significant shallow slip deficit. The main fault consists of two asperities, which is bounded by an aftershock gap may representing a barrier. In addition, we find that most of the aftershocks were located down-dip of the high-slip areas and laid in stress shadows. We deduce that the aftershocks may be controlled by the background tectonic stress field, and may be related to the velocity-strengthening zones.


2015 ◽  
Vol 58 (2) ◽  
Author(s):  
Manuela Volpe ◽  
Simone Atzori ◽  
Antonio Piersanti ◽  
Daniele Melini

<p>We present a Finite Element inverse analysis of the static deformation field for the M<sub>w</sub>= 6.3, 2009 L’Aquila earthquake, in order to infer the rupture slip distribution on the fault plane. An univocal solution for the rupture slip distribution has not been reached yet with negative impact for reliable hazard scenarios in a densely populated area. In this study, Finite Element computed Green’s functions were implemented in a linear joint inversion scheme of geodetic (GPS and InSAR) and seismological (strong motion) coseismic deformation data. In order to fully exploit the informative power of our dense dataset and to honor the complexities of the real Earth, we implemented an optimized source model, represented by a fault plane subdivided in variable size patches, embedded in a high-resolution realistic three-dimensional model of the Apenninic seismo-tectonic setting, accounting for topographic reliefs and rheological heterogeneities deduced from local tomography. We infer that the investigated inversion domain contains two minima configurations in the solution space, i.e. a single- and a double-patch slip distribution, which are almost equivalent, so that the available datasets and numerical models are not able to univocally discriminate between them. Nevertheless our findings suggest that a two high-slip patch pattern is slightly favoured.</p>


2020 ◽  
Vol 12 (22) ◽  
pp. 3721
Author(s):  
Zhongqiu He ◽  
Ting Chen ◽  
Mingce Wang ◽  
Yanchong Li

The 2016 Kumamoto earthquake, including two large (Mw ≥ 6.0) foreshocks and an Mw 7.0 mainshock, occurred in the Hinagu and Futagawa fault zones in the middle of Kyushu island, Japan. Here, we obtain the complex coseismic deformation field associated with this earthquake from Advanced Land Observation Satellite-2 (ALOS-2) and Sentinel-1A Interferometric Synthetic Aperture Radar (InSAR) data. These InSAR data, in combination with available Global Positioning System (GPS) data, are then used to determine an optimal four-segment fault geometry with the jRi method, which considers both data misfit and the perturbation error from data noise. Our preferred slip distribution model indicates that the rupture is dominated by right-lateral strike-slip, with a significant normal slip component. The largest asperity is located on the northern segment of the Futagawa fault, with a maximum slip of 5.6 m at a 5–6 km depth. The estimated shallow slips along the Futagawa fault and northern Hinagu fault are consistent with the displacements of surface ruptures from the field investigation, suggesting a shallow slip deficit. The total geodetic moment release is estimated to be 4.89 × 1019 Nm (Mw 7.09), which is slightly larger than seismological estimates. The calculated static Coulomb stress changes induced by the preferred slip distribution model cannot completely explain the spatial distribution of aftershocks. Sensitivity analysis of Coulomb stress change implies that aftershocks in the stress shadow area may be driven by aseismic creep or triggered by dynamic stress transfer, requiring further investigation.


2016 ◽  
Vol 687 ◽  
pp. 210-222 ◽  
Author(s):  
Athanassios Ganas ◽  
Panagiotis Elias ◽  
George Bozionelos ◽  
George Papathanassiou ◽  
Antonio Avallone ◽  
...  

Author(s):  
Chunyan Qu ◽  
Ronghu Zuo ◽  
Xin Jian Shan ◽  
Guohong Zhang ◽  
Yingfeng Zhang ◽  
...  

On September 16, 2015, a magnitude 8.3 earthquake struck west of Illapel, Chile. We analyzed Sentinel-1A/IW InSAR data on the descending track acquired before and after the Chile Mw8.3 earthquake of 16 September 2015. We found that the coseismic deformation field of this event consists of many semi circular fringes protruding to east in an approximately 300km long and 190km wide region. The maximum coseismic displacement is about 1.33m in LOS direction corresponding to subsidence or westward shift of the ground. We inverted the coseismic fault slip based on a small-dip single plane fault model in a homogeneous elastic half space. The inverted coseismic slip mainly concentrates at shallow depth above the hypocenter with a symmetry shape. The rupture length along strike is about 340 km with maximum slip of about 8.16m near the trench. The estimated moment is 3.126×1021 N.m (Mw8.27),the maximum depth of coseismic slip near zero appears to 50km. We also analyzed the postseismic deformation fields using four interferograms with different time intervals. The results show that postseismic deformation occurred in a narrow area of approximately 65km wide with maximum slip 11cm, and its predominant motion changes from uplift to subsidence with time. that is to say, at first, the postseismic deformation direction is opposite to that of coseismic deformation, then it tends to be consistent with coseismic deformation.It maybe indicates the differences and changes in the velocity between the Nazca oceanic plate and the South American continental plate.


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