High-frequency ground motion and source characteristics of the 2008 Wenchuan and 2013 Lushan, China, earthquakes

Pure & Applied Geophysics
By: , and 

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Abstract

The 2008 MW7.9 Wenchuan and the 2013 MW6.6 Lushan earthquakes, which both occurred on the Longmen Shan thrust belt, show some interesting similarities and differences. Whereas the Wenchuan earthquake entailed a rupture zone that extended about 300 km northeastward, with fault slip extending to the surface, the Lushan earthquake was the result of a buried and much more compact zone of rupture. The high-frequency ground motions, however, for these two earthquakes, as measured by the peak ground acceleration, were evidently influenced by neither the extent of rupture nor the presence or absence of surface rupture. The source parameters for these two earthquakes tend to confirm the idea that high-frequency ground motion is controlled by stress changes in the rupture zone that give rise to the radiated ground acceleration. The apparent stresses for the Wenchuan and Lushan earthquakes are about 0.5 and 0.75 MPa, respectively, and the stress drops, in the same order, are about 2.5 and 3.5 MPa. The ratios of average stress drop to apparent stress are in the range 4.5–5 for both events, consistent with expectations based on the Brune (J Geophys Res 75(26):4997–5009, 1970) source model.

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Publication type Article
Publication Subtype Journal Article
Title High-frequency ground motion and source characteristics of the 2008 Wenchuan and 2013 Lushan, China, earthquakes
Series title Pure & Applied Geophysics
DOI 10.1007/s00024-019-02291-4
Volume 177
Publication Date August 08, 2019
Year Published 2019
Language English
Publisher Springer
Contributing office(s) Earthquake Science Center
Description 13 p.
First page 81
Last page 93
Country China
Other Geospatial Lushan, Wenchuan
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