Rupture processes and Coulomb stress changes of the 2017 Mw 6.5 Jiuzhaigou and 2013 Mw 6.6 Lushan earthquakes

Xin Lin,Xiangfang Zeng,Risheng Chu

doi:10.1186/s40623-019-1061-3

Xin Lin, Xiangfang Zeng + Show 1 more

Open Access

https://doi.org/10.1186/s40623-019-1061-3

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Abstract

Since the 2008 great Mw 7.9 Wenchuan earthquake, two destructive earthquakes, the 2013 Mw 6.6 Lushan earthquake and the 2017 Mw 6.5 Jiuzhaigou earthquake, struck the eastern margin of the Tibetan Plateau, causing many casualties and significant property damage. The rupture processes and Coulomb stress change of the Lushan and Jiuzhaigou earthquakes are investigated in this study. The general patterns of the slip models of the two events are similar, where the slip is concentrated around the hypocenter and the primary ruptured zone extends about 20 km along strike. The rupture zone of the 2017 Jiuzhaigou earthquake spans a depth range of 4–16 km with a peak slip of ~ 115 cm, whereas the rupture zone of the 2013 Lushan earthquake is concentrated at 8 to 20 km depth with a peak slip of 125 cm. The coseismic static Coulomb stress changes induced by the two events are computed with the obtained slip models. The Tazang fault and the northern extremities of the Minjiang and Huya faults were strongly loaded by the Jiuzhaigou earthquake, whereas the Lushan earthquake mainly affected its surrounding faults. Therefore, we infer that the seismic hazard potential in these regions has probably been increased further, and the Lushan earthquake did not contribute significantly the occurrence of the Jiuzhaigou earthquake. Additionally, we also compute the stress changes imparted by the 2008 Wenchuan earthquake. The computed stress changes in both events’ hypocenters exceed the trigger threshold (0.1 bar), which suggests that the Wenchuan earthquake played a pivotal role in the occurrence of these two earthquakes.

Highlights

On May 12, 2008, the disastrous Mw 7.9 Wenchuan earthquake occurred on the central-northern segments of the Longmen Shan fault zone near the eastern margin of the Tibetan Plateau
We explore the relationships among the Wenchuan earthquake, the Jiuzhaigou earthquake and the Lushan earthquake using teleseismic data
Regarding the Coulomb stress change, the Wenchuan earthquake produced a significant impact on the surrounding area

Summary

Introduction

On May 12, 2008, the disastrous Mw 7.9 Wenchuan earthquake occurred on the central-northern segments of the Longmen Shan fault zone near the eastern margin of the Tibetan Plateau. The earthquake caused large ground deformations and accumulation of stresses in a wide area (Parsons et al 2008; Toda 2008; Shen et al 2009; Hashimoto et al 2010; Luo and Liu 2010; Wan and Shen 2010; Nalbant and Mccloskey 2011; Wang et al 2011; Zhang et al 2015), resulting in nearly 70,000 fatalities and destroying millions of buildings Two strong earthquakes, the 2013 Mw 6.6 Lushan and the 2017 Mw 6.5 Jiuzhaigou earthquakes struck the eastern margin of the Tibetan Plateau and induced many casualties and significant property damage (https://reliefweb.int/disaster/eq-2013-00004 6-chn; https://edition.cnn.com/2017/08/08/asia/china-earthquake/index.html). The earthquake took place about 250 km northwest of the Wenchuan earthquake, whereas the Lushan earthquake occurred on the southern segment of the Longmen Shan fault zone (Fig. 1). Xie et al (2018) investigated the rupture process, and the Coulomb stress change of the Jiuzhaigou earthquake, but

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