SEISMO-GEOLOGICAL SIGNATURES FOR IDENTIFYING M≥7.0 EARTHQUAKE RISK AREAS AND THEIR PREMILIMARY APPLICATION IN MAINLAND CHINA |
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| Authors: | XU Xi-wei WU Xi-yan YU Gui-hua TAN Xi-bin LI Kang |
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| Institution: | Key Laboratory of Active Tectonics and Volcanos, Institute of Geology, China Earthquake Administration, Beijing 100029, China |
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| Abstract: | High-magnitude earthquake refers to an earthquake that can produce obvious surface ruptures along its seismogenic fault and its magnitude M is at least equal to 7.0. Prediction and identification of locations, where the high-magnitude earthquakes will occur in potential, is one of the scientific goals of the studies on long-term faulting behavior of active faults and paleo-earthquakes, and is also the key problem of earthquake prediction and forecast. The study of the geological and seismological signatures for identifying M≥7.0 earthquake risk areas and their application is an important part of seismic prediction researches. It can not only promote the development of earthquake science, especially the progress of earthquake monitoring and forecasting, but also be positive for earthquake disaster prevention and effective mitigation of possible earthquake disaster losses. It is also one of the earthquake science problems which the governments, societies and the scientific communities are very concerned about and need to be addressed.
Large or great earthquakes, such as the 2008 Wenchuan earthquake(M8.0), the 2010 Yushu earthquake(M7.1), the 2013 Lushan earthquake(M7.0)and the 2015 Gorkha earthquake(MW7.8), have unceasingly struck the Qinghai-Tibet Plateau and its surrounding areas, which have been attracting attention of a large number of geoscientists both at home and abroad. Owing to good coverage of the seismic networks and GPS sations, a lot of high-quality publications in seismicity, crustal velocity structure, faulting beihavior have been pressed, which gives us a good chance to summarize some common features of these earthquakes. In this paper, seismogenic structural model of these earthquakes, faulting behavior of seismogenic faults, crustal mechanical property, recent straining environment and pre-earthquake seismicity are first analyzed, and then, five kinds of common features for the sismogenic faults where those earthquakes occurred. Those five kinds of commom features are, in fact, the geological and seismological signatures for identifying M≥7.0 earthquake risk areas. The reliability of the obtained sigatures is also discussed in brief. At last, based on the results of 1:50000 active fault mapping, and published seismic tomography and fault-locking studies, an experimental identification of the risk areas for the future large/great earthquakes in the North China and the Qinghai-Tibet Plateau is conducted to test the scientificity and applicability of these obtained sigantures. |
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| Keywords: | high-magnitude earthquake seismo-geological signature earthquake risk area mainland China |
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