caa a22 4500 445301228 CHVBK 20180317142558.0 cr unu---uuuuu 170323e20101101xx s 000 0 eng 10.1007/s11430-010-4026-8 doi (NATIONALLICENCE)springer-10.1007/s11430-010-4026-8 A shallow aftershock sequence in the north-eastern end of the Wenchuan earthquake aftershock zone [Elektronische Daten] [Yan Luo, SiDao Ni, XiangFang Zeng, Yong Zheng, QiFu Chen, Yong Chen] Previous studies show that mature faults are filled with fault gouge in the shallow part and thus cannot accumulate enough strain energy for earthquakes. Therefore most earthquakes are deeper than 5 km, except those events occurring on new faults or in intact rocks. From field observation, Wenchuan earthquake is found to rupture the free surface about 200 km, but the rupture may extend underground much further from teleseismic body waves inversion and aftershocks distribution. In the northeastern end of the rupture zone, deep rupture may induce stress increase near the free surface, and trigger shallow earthquakes. An M s 5.7 aftershock occurred at Qingchuan, northeast end of Wenchuan earthquake fault on July 24, 2008, featuring thrust mechanism with a 3 km source centroid depth. The shallow focal depth is confirmed with the sPL phase recorded at station L0205. As Rayleigh wave is well only developed for source depth less than 1/5 of epicentral distance, the observed large amplitude of Rg at a distance of 15 km implied depth of 3 km or less. Dozens of aftershocks' sPL waveforms are also analyzed to confirm the source depths less than 3 km. On the other hand, no surface ruptures are found by geological survey or InSAR studies. It is strongly suggested that these aftershock sequences initiate fresh rupture in intact rocks triggered by stress increase from the deep co-seismic rupture of the Wenchuan mainshock. Science China Press and Springer-Verlag Berlin Heidelberg, 2010 Wenchuan earthquake nationallicence shallow earthquake nationallicence focal depth nationallicence wave modeling nationallicence Luo Yan School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut Ni SiDao School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut Zeng XiangFang School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut Zheng Yong Institute of Geodesy and Geophysics, Chinese Academy of Sciences, 430077, Wuhan, China aut Chen QiFu Institute of Earthquake Science, China Earthquake Administration, 100036, Beijing, China aut Chen Yong Institute of Earthquake Science, China Earthquake Administration, 100036, Beijing, China aut Science China Earth Sciences SP Science China Press 53/11(2010-11-01), 1655-1664 1674-7313 53:11<1655 2010 53 11430 https://doi.org/10.1007/s11430-010-4026-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11430-010-4026-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Luo Yan School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut NATIONALLICENCE 700 1- Ni SiDao School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut NATIONALLICENCE 700 1- Zeng XiangFang School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China aut NATIONALLICENCE 700 1- Zheng Yong Institute of Geodesy and Geophysics, Chinese Academy of Sciences, 430077, Wuhan, China aut NATIONALLICENCE 700 1- Chen QiFu Institute of Earthquake Science, China Earthquake Administration, 100036, Beijing, China aut NATIONALLICENCE 700 1- Chen Yong Institute of Earthquake Science, China Earthquake Administration, 100036, Beijing, China aut NATIONALLICENCE 773 0- Science China Earth Sciences SP Science China Press 53/11(2010-11-01), 1655-1664 1674-7313 53:11<1655 2010 53 11430 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer