Precursory Anomaly and Analysis of Cangyuan MS 5.5 Earthquake in Yunnan in 2015
XU Jiaqian
YANG Xiaolin
Abstract：Based on a comprehensive analysis of the focal mechanism solution, isoseismal line distribution of intensity and the trend of aftershock zones of Cangyuan M 5.5 earthquake on March 1st, 2015, it is believed that the west branch of Nanting River fault is the seismogenic structure of this earthquake. The study of spatiotemporal dynamics evolution of foreshock activities before earthquake shows that before earthquake the epicenter's range is about 150 km, small earthquake activities begin to increase and appear abnormal phenomena eight months before the principal earthquake, and the accumulative frequency of earthquake activities further accelerates development 3 months before earthquake, and reaches its maximum 13 days before earthquake, then enters the highly calm phase of the imminent earthquake before earthquake. There existed an identifiable seismogenic zones before earthquake, and according to the largest scale and the largest foreshock of this seismogenic zone, the future main shock magnitude can be quantitatively calculated. At the same time, the north east component of cave strain and water pipe tilted in Gengma county and Yun county appeared the annual variation; through the seismogenic process analysis of this earthquake, it is considered that the middle phase, short phase and temporary phase of the preparation of Cangyuan M 5.5 earthquake, are all trackable and computable, which provides a reference for the monitoring of destructive earthquakes in this area in the future.
Keywords：Cangyuan MS 5.5 earthquakePrecursory anomalyAnomaly characteristicNantinghe fault zone
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 39-47 )