Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake

Shen, Zheng‐Kang; Sun, Jianbao; Zhang, Peizhen; Wan, Yizhao; Wang, Min; Bürgmann, Roland; Zeng, Yuehua; Gan, Weijun; Liao, Hua; Wang, Qingliang

doi:10.1038/ngeo636

Cited by 514 publications

(582 citation statements)

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“…Significant coseismic offsets and post-seismic deformation caused by the 2008 M W 7.9 Wenchuan earthquake were identified within the Sichuan Basin and the west of the Longmenshan fault (Shen et al 2009;Wang et al 2011). Therefore, removal of the effect of the Wenchuan earthquake on site velocities is prerequisite in deriving reliable site velocities.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Meng

et al. 2015

Earthq Sci

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The eastern margin of Tibetan Plateau is one of the most active zones of tectonic deformation and seismicity in China. To monitor strain buildup and benefit seismic risk assessment, we constructed 14 survey-mode global position system (GPS) stations throughout the northwest of Longmenshan fault. A new GPS field over 1999-2011 is derived from measurements of the newly built and pre-existing stations in this region. Sequentially, two strain rate fields, one preceding and the other following the 2008 M W 7.9 Wenchuan earthquake, are obtained using the Gausian weighting approach. Strain field over 1999-2007 shows distinct strain partitioning prior to the 2008 M W 7.9 Wenchuan earthquake, with compression spreading over around Longmenshan area. Strain field derived from the two measurements in 2009 and 2011 shows that the area around Longmenshan continues to be under striking compression, as the pattern preceding the Wenchuan earthquake, implying a causative factor of the sequent of 2013 M W 6.7 Lushan earthquake. Our GPSderived dilatation shows that both the Wenchuan and Lushan earthquakes occurred within the domain of pronounced contraction. The GPS velocities demonstrate that the Longriba fault underwent slight motion with the faultnormal and -parallel rates at 1.0 ± 2.5 mm and 0.3 ± 2.2 mm/a; the Longmenshan fault displayed slow activity, with a fault-normal rate at 0.8 ± 2.5 mm/a, and a fault-parallel rate at 1.8 ± 1.7 mm/a. Longriba fault is on a par with Longmenshan fault in strain partitioning to accommodate the southeastward motion of eastern margin of the Tibetan Plateau. Integrated analysis of principal strain tensors, mean principal stress, and fast directions of mantle anisotropy shows that west of Sichuan is characterized as mechanically strong crust-mantle coupling.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Meng

et al. 2015

Earthq Sci

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“…In this paper, we further confirm the main conclusion given by Cai et al (2011) with emphasis that they distribute unevenly. First, the southern part of the Longmenshan fault released more elastic energy by this type of events than the northern part, which is illustrated by both source inversion results of the main shock (e.g., Ji and Hayes 2008;Shen et al 2009) and the aftershock distribution shown in this paper.…”

Section: Characteristics Of the Fmssmentioning

confidence: 88%

“…Events 27, 53, 56, 87, and 114, low quality event 205 either, which located around Beichuan, might play similar role as well but might mainly for right-lateral strike-slip motion of the Longmenshan fault at Beichuan where was the second place of maximum energy releasing of the 2008 Wenchuan earthquake (e.g., Ji and Hayes 2008;Wang et al 2009;Liu-Zeng et al 2009;Shen et al 2009). So did events 49, 33, 123, 2, 111, 115, 116, and 201 but to the opposite site of Beichuan although 115, 116, and 201 might have been triggered mainly by the thrust events around Maoxian.…”

Section: Triggering Role Of Some Biggest Events Of Wes On Othersmentioning

confidence: 99%

“…A short pause between the motions of the two regions and intensity variation of the rupture along the Longmenshan fault during the 2008 Wenchuan earthquake, as well as great aftershock activity around Maoxian, are all manifestations for more complex triggering role. However, after realizing that the great energy released around Gaochuan-Beichuan in the main shock (e.g., Ji and Hayes 2008;Zhang et al 2009;Shen et al 2009;Wang et al 2011) and some aftershocks which might stand for releasing of the local elastic energy produced by the strike-slip motion around Beichuan in the main shock, we have to adjust our understanding and claim that low seismicity and diversity of the FMSs around Beichuan area after the main shock might be mainly the results of nearly fully energy releasing of it in the main shock although we still think that there is relatively less elastic energy accumulation in the middle part of the Longmenshan fault, keeping the judge that there is less risk of great earthquakes in the near future around there.…”

Section: Broken Barriers and Ready-to-be-broken Barriermentioning

confidence: 99%

“…The first peak was near Yingxiu-Hongkou, Wenchuan about 10-20 s after the initial burst, and the second energy peak came 50 s later near Beichuan. The largest thrust slip is found on the moderately dipping thrust fault near Yingxiu-Hongkou and the largest strike slip is located near Beichuan (e.g., Shen et al 2009;Wang et al 2011). Hu et al (2008) preliminarily determined 44 FMSs of strong aftershocks using P-wave first-motion polarities (PWFMP) and a revised Grid Search Method named CHNYTX ).…”

Section: Introductionmentioning

confidence: 99%

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Focal Mechanism Solutions of the 2008 Wenchuan earthquake sequence from P-wave polarities and SH/P amplitude ratios: new results and implications

Tian

Ning

Yu³

et al. 2013

Earthq Sci

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The 2008 Wenchuan earthquake, a major intraplate earthquake with M w 7.9, occurred on the slowly deforming Longmenshan fault. To better understand the causes of this devastating earthquake, we need knowledge of the regional stress field and the underlying geodynamic processes. Here, we determine focal mechanism solutions (FMSs) of the 2008 Wenchuan earthquake sequence (WES) using both P-wave first-motion polarity data and SH/P amplitude ratio (AR) data. As P-wave polarities are more reliable information, they are given priority over SH/

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Sensitivity of Coulomb stress change to the parameters of the Coulomb failure model: A case study using the 2008 M_w 7.9 Wenchuan earthquake

Wang

Freymueller

et al. 2014

JGR Solid Earth

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The Coulomb stress change has been widely employed to interpret mainshock-mainshock and mainshock-aftershock triggering as well as interactions amongst earthquake faults and volcanoes. This quantitative index is computed based on the Coulomb failure criterion and is a function of fault parameters including the source and receiver fault geometries, the friction coefficient on the receiver fault, and Skempton's coefficient of the host rock. Thus, for the robust determination of the Coulomb stress change, the sensitivity of the Coulomb stress change to these model parameters should be thoroughly assessed. However, notwithstanding numerous case studies, almost no systematic investigation of the sensitivity of the Coulomb stress change has been performed. Here we present an error estimator for the Coulomb stress change and then quantitatively investigate the sensitivity of the Coulomb stress change to the fault model parameters for the 2008 M w 7.9 Wenchuan earthquake. Our results indicate that for this case the Coulomb stress change is the most sensitive to the uncertainty in the dip angle of the receiver fault, while the influences of the uncertainties in the slip model of the source fault, the strike, and rake angles of the receiver fault, and the friction and Skempton's coefficients cannot be neglected. Accordingly, it is crucial to perform a realistic estimate of the uncertainty in the Coulomb stress change. By performing such calculation, future Coulomb stress analyses such as the stress triggering of earthquake sequence and the likelihoods of potential earthquakes could be based on more robust Coulomb stress change maps.

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Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake

Cited by 514 publications

References 17 publications

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Focal Mechanism Solutions of the 2008 Wenchuan earthquake sequence from P-wave polarities and SH/P amplitude ratios: new results and implications

Sensitivity of Coulomb stress change to the parameters of the Coulomb failure model: A case study using the 2008 M_w 7.9 Wenchuan earthquake

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Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake

Cited by 514 publications

References 17 publications

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Focal Mechanism Solutions of the 2008 Wenchuan earthquake sequence from P-wave polarities and SH/P amplitude ratios: new results and implications

Sensitivity of Coulomb stress change to the parameters of the Coulomb failure model: A case study using the 2008 Mw 7.9 Wenchuan earthquake

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Sensitivity of Coulomb stress change to the parameters of the Coulomb failure model: A case study using the 2008 M_w 7.9 Wenchuan earthquake