
Seismic imaging of aftershock gap between Lushan and Wenchuan earthquakes
GAO Lina
Global Geology ›› 2017, Vol. 20 ›› Issue (2) : 112-117.
Seismic imaging of aftershock gap between Lushan and Wenchuan earthquakes
New Vp and Vs models of the aftershock gap between the 2013 Lushan and 2008 Wenchuan earthquakes were obtained using 7190 events recorded by 102 stations in the southeastern margin of the Tibetan Plateau. The new velocity models and event locations were inverted by the regional-scale version of double-difference tomography algorithm. The new velocity structure shows that the aftershock gap is an obviously low-velocity zone in the upper crust, whereas the aftershock regions of the Lushan and Wenchuan earthquakes show high-velocity anomalies. The low-velocity anomaly of the aftershock gap in the upper crust may indicate that the materials of the gap are weak and ductile, which is not prone to accumulate stress and cause big earthquakes. As a result, it is less likely that the big earthquakes will occur in the gap in the future.
aftershock gap / Wenchuan earthquake / Lushan earthquake / double-difference tomography
Bai D H, Unsworth M J, Meju M A, et al. 2010. Crustal deformation of the eastern Tibetan plateau revealed by magnetotelluric imaging. Nature Geoscience, 3(5): 358-362.
Burchfiel B C, Royden L H, van der Hilst R D, et al. 2008. A geological and geophysical context for the Wenchuan earthquake of 12 May 2008, Sichuan, People's Republic of China. GSA Today, 18(7). doi: 10.1130/GSATG18A.1.
Hu S B, He L J, Wang J Y. 2000. Heat flow in the continental area of China: a new data set. Earth and Planetary Science Letters, 179(2): 407-419.
Liu Q Y, van der Hilst R D, Li Y, et al. 2014. Eastward expansion of the Tibetan Plateau by crustal flow and strain partitioning across faults. Nature Geoscience, 7(5): 361-365.
Nishimura N, Yagi Y. 2008. Preliminary results of coseismic-slip for the 2008 Mw 7.9 Wenchuan Earthquake Southwest
[JP2]China, 2008. http://www.geol.tsukuba.ac.jp/~nisimura/20080512/.
[JP]
Pei S P, Zhang H J, Su J R, et al. 2014. Ductile gap between the Wenchuan and Lushan earthquakes revealed from the two-dimensional Pg seismic tomography. Scientific reports, doi: 10.1038/srep06489.
Wang Z, Wang J, Chen Z L, et al. 2011. Seismic imaging, crustal stress and GPS data analyses: Implications for the generation of the 2008 Wenchuan Earthquake (M7. 9), China. Gondwana Research, 19(1): 202-212.
Wang Z, Su J R, Liu C X, et al. 2015. New insights into the generation of the 2013 Lushan Earthquake (Ms 7.0), China. Journal of Geophysical Research: Solid Earth, 120. doi:10.1002/2014JB011692.
Xu L L, Rondenay S R, van der Hilst R D. 2007. Structure of the crust beneath the southeastern Tibetan Plateau from teleseismic receiver functions. Physics of the earth and planetary interiors, 165(3): 176-193.
Xu X W, Wen X Z, Han Z J, et al. 2013. Lushan MS 7.0 earthquake: a blind reserve-fault event. Chinese Science Bulletin, 58: 3437-3443.
Xu Z Q, Ji S C, Li H B, et al. 2008. Uplift of the Longmen Shan range and the Wenchuan earthquake. Episodes, 31(3): 291-301.
Zhang H J, Roecker S, Thurber C H, et al. 2012. Seismic imaging of microblocks and weak zones in the crust beneath the southeastern margin of the Tibetan Plateau. http://www.doc88.com/p-370140396938.html
Zhang H J, Thurber C H. 2003. Double-difference tomography: The method and its application to the Hayward Fault, California. Bulletin of the Seismological Society of America, 93(5): 1875-1889.
Zhang H J, Thurber C H. 2006. Development and applications of double-difference seismic tomography. Pure and Applied Geophysics, 163(2/3): 373-403.
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