ANALYSIS AND THINKINGS ABOUT THE ORIGIN AND BACKGROUND OF 2010 YUSHU EARTHQUAKE

The 2010 Yushu earthquake, originated in Qinghai, struck on April 14, 2010, and registered a magnitude of M_S 7.1. This paper discusses the origin and background of the earthquake and gives some advices about post-disaster reconstruction. Considering the geotectonic settings, the authors attributes the origin of 2008 Wenchuan earthquake and 2010 Yushu earthquake to the Indian plate' s wedging in Qinghai-Tibet Plateau, which driving the material of curst-mantle under QinghaiTibet Plateau creeping to east and then caused the earthquakes. The Qinghai-Tibet Plateau consists of several different blocks, they were collaged together in Mesozoic and Cenozoic. The movement and collision of these blocks extruded by the Indian plate are the main reasons of those earthquakes around Qinghai-Tibet Plateau in last several years. Just because the eastward movement of Kunlun block leading to the sinistral slip of Yushu-Xianshuihe Fault, then caused the 2010 Yushu earthquake. Until now, the eastward movement of Kunlun block had caused three earthquakes with the magnitude of M_S 7 to M_S 8, massive accumulated energy had been released. So, the emphasis should be focused on the southeastward moving Qiangtang-Litang block and a strict surveillance must be kept on it. Learned from 2008 Wenchuan earthquake, the region with less movement by GPS always tend to be a center of energy accumulating because the block is resisted by other hard blocks, and is likely to be the region where earthquake will strike. The authors proposed that the following areas could be struck by earthquakes: Yuxi, Tonghai and Shiping areas in the south of Kunming; Dali area; Yanyuan and Yantang areas of western Sichuan Province; Ya' an, Luding and Kangding areas, which are the cross section of Yushu-Xianshuihe Fault and Longmen Mountain Fault. All of the four areas locate on the frontier of southward arciform thrust-nappe structure zones formed in late Cenozoic, and they likely to be the stress concentration regions when obstructing the movement of Qiangtang-Litang block. High attention with dynamic monitoring should be paid to in these areas suggested.