Initial rupture processes of the 2008 Mw7.9 Wenchuan, China earthquake: From near-source seismic records

Gong, Meng; Xu, Xiwei; Shen, Yang; Huang, Bor-Shouh; Li, Kang

doi:10.1016/j.jseaes.2019.01.040

Cited by 6 publications

(3 citation statements)

References 24 publications

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“…Currently, how precise the seismic relocation results are for the earthquakes that occurred in the transition zone between orogenic belt and sedimentary basin is a subject of debate, mainly because the relocation algorithms cannot fully incorporate the effects of the subcrustal material heterogeneities and structural complexities. For example, even 12 years after the 2008 M W 7.9 Wenchuan earthquake, we still do not know the exact position of the hypocenter: the inferred depths vary considerably (8.4-19 km) (Gong et al, 2019). More specifically, initial rupture was found at S15 km depth based on a high-angle listric-reverse fault model of the Longmenshan fault system (Zhang et al, 2009, Zhang et al, 2012, whereas a much shallower depth of &10 km was also proposed based on a steep reverse fault model (Xu et al, 2009;Hubbard and Shaw, 2009;Gong et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…For example, even 12 years after the 2008 M W 7.9 Wenchuan earthquake, we still do not know the exact position of the hypocenter: the inferred depths vary considerably (8.4-19 km) (Gong et al, 2019). More specifically, initial rupture was found at S15 km depth based on a high-angle listric-reverse fault model of the Longmenshan fault system (Zhang et al, 2009, Zhang et al, 2012, whereas a much shallower depth of &10 km was also proposed based on a steep reverse fault model (Xu et al, 2009;Hubbard and Shaw, 2009;Gong et al, 2019). Usually, strong motion data (Zhang et al, 2012) and geodetic measurements (Shen et al, 2009;Feng et al, 2010) are used to get a precise estimate of the earthquake locations and to infer seismogenic structure, but the results are still biased because the models still miss enough details of the material and structural complexities.…”

Section: Discussionmentioning

confidence: 99%

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The 2020 M6.4 Jiashi Earthquake: An Event that Occurred Under the Décollement on the Kaping Fold-and-Thrust Belt in the Southwestern Tien Shan Mountains, China

et al. 2021

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The 2020 Jiashi M6.4 earthquake occurred in the Kaping fold-and-thrust belt, a major south-verging active thin-skin system in the southwestern Chinese Tien Shan Mountain, north of the Tarim Basin. Within 50 km from the epicentral area, seismic hazard is high, as suggested by the occurrence of the 1902 Mw 7.7 Artux (Kashgar) earthquake and 1997 Jiashi strong earthquake swarm. The seismogenic structure responsible for the 2020 event is not well constrained and is a subject of debate. We relocated the 2020 Jiashi earthquake sequence and assessed the relocation uncertainties, using eight seismic velocity models and based on detailed local and regional subcrustal structures from seismic profiles. Then we compared the temporal variation in the Gutenberg–Richter b-values of the 2020 sequence with those of the 1997, 1998, and 2003 earthquake sequences. Our results show that most events cluster at depths greater than 10 km, suggesting that the events most likely occurred beneath the décollement and inside the Tarim Craton. The spatiotemporal evolution of the sequence suggests that two groups of structures at depth were involved in the 2020 sequences: NW–SE-trending lateral strike-slip faults and E–W-trending reverse faults. The b-values of the 2020 sequence exhibits relatively stable temporal evolution, unlike those of the multi-shock sequence that occurred inside the Tarim Craton. It indicates that the 2020 sequence perhaps was influenced by the stress interaction with the 10 km thick overlying strata. Our study provides a new perspective on the seismogenic structure of the earthquakes that occurred because of reactivation of ancient structures developed in a stable craton.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The 2020 M6.4 Jiashi Earthquake: An Event that Occurred Under the Décollement on the Kaping Fold-and-Thrust Belt in the Southwestern Tien Shan Mountains, China

et al. 2021

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“…The field investigations (Xu et al, ) and deep drilling works (Li et al, ; Xue et al, ) try to investigate this earthquake by local observations. Based on previous studies, the general skeleton of the Wenchuan earthquake can be drawn, that the great earthquake occurred on a fault system with a complex geometry (Figure ), had a moment magnitude of Mw 7.9, and initialized at a depth of approximately 19 km (Zhang et al, ), although some debates may remain (Gong et al, ). Generally, the fault system consists of three main obvious rupture faults: the Beichuan Fault, Pengguan Fault, and Xiaoyudong Fault.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Rupture Simulations of the 2008 Mw 7.9 Wenchuan Earthquake by the Curved Grid Finite‐Difference Method

Zhang

Chen

2019

JGR Solid Earth

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Enough investigations and observations have been undertaken to suggest that the great 2008 Mw 7.9 Wenchuan earthquake of China ruptured in a highly complex pattern. The causative fault of the Wenchuan earthquake has a complex geometry, divided into several segments with offsets of a few kilometers. Modeling the dynamic rupture of this earthquake with geometrical complexity is a challenge. In this work, we simulated the dynamic rupture on the geometrically complex fault of the 2008 Mw 7.9 Wenchuan earthquake of China by the curved grid finite-difference method. In our modeling, a uniform background tectonic stress field with tapering at shallow depth and slip-weakening law with homogeneous friction coefficients are utilized. We found that the typical heterogeneous spatial distribution of the final seismic slip on the fault can be generated by the nonplanar complex geometry of the fault plane. Moreover, we discussed the geometrical effects of the Wenchuan earthquake on the rupture dynamics and strong ground motion. We found that the complexity of fault geometry results in the rupture complexity of the great Wenchuan earthquake. This work provides us with a new insight into the rupture dynamics of the Wenchuan earthquake.

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Initial rupture sequence and rupture history of the 2008 Wenchuan earthquake from a kinematic perspective

Yin,

Zeng,

Chen

et al. 2024

Nat Hazards

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A reasonable three-dimensional complex fault model was established by comprehensively considering the three-dimensional seismic structure model, aftershock distribution, and surface rupture investigation. Two possible rupture modes were adopted, and based on parallel non negative least squares method and multi time window technology, combined with far-eld, near-eld, GPS, and surface rupture data, the precise rupture process of the Wenchuan earthquake was inverted, and a reasonable rupture mode was provided. The results are as follows: (1) The occurrence of bilateral rupture at the intersection of the Beichuan fault and the Xiaoyudong fault is more in line with the actual situation for the Wenchuan earthquake. When the bilateral rupture occurs, dislocations that match the observed surface rupture are generated in the near surface area from Hongkou to Yingxiu. The synthetic records amplitude of the station in the near eld behind the rupture direction is closer to the observation record.(2) The joint inversion results show that the duration of the Wenchuan earthquake rupture reached 100s, and the released seismic moment was 1.058×10 21 N•m. There are 5 asperities on the fault plane, indicating that this earthquake is composed of at least 5 subevents. The slip is mainly distributed on the Beichuan Fault, indicating that the Beichuan Fault is the main rupture fault.

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Initial rupture processes of the 2008 Mw7.9 Wenchuan, China earthquake: From near-source seismic records

Cited by 6 publications

References 24 publications

The 2020 M6.4 Jiashi Earthquake: An Event that Occurred Under the Décollement on the Kaping Fold-and-Thrust Belt in the Southwestern Tien Shan Mountains, China

The 2020 M6.4 Jiashi Earthquake: An Event that Occurred Under the Décollement on the Kaping Fold-and-Thrust Belt in the Southwestern Tien Shan Mountains, China

Dynamic Rupture Simulations of the 2008 Mw 7.9 Wenchuan Earthquake by the Curved Grid Finite‐Difference Method

Initial rupture sequence and rupture history of the 2008 Wenchuan earthquake from a kinematic perspective

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