Anomalous seismic activities in the Sichuan--Yunnan region and its adj acent areas before the Lushan MS7 .0 earthquake by the pattern informatics method
Zhang Xiaotao
Zhang Yongxian
Xia Caiyun
Wu Yongjia
Yu Huaizhong
Abstract：The Pattern Informatics (PI )method is a new approach for earth-quake prediction based on statistical physics.This method can detect the re-gions where seismicity significantly deviates from the normal state (i.e.,seismic quiescence or seismic activation),known as “seismic hotspots”,via strict sta-tistical tests.Previous results show that PI is effective for medium- to long-term earthquake prediction.In this paper,after declustering and choosing complete-ness magnitude,the PI method was applied to earthquake catalogue from China Earthquake Networks Center since 1970,to detect the existence of seismic hotspots before the Lushan MS7.0 earthquake on April 20,2013.Based on suit-able parameters (with grid size of 2°×2°and forecast window of 9 years)with higher prediction efficiency according to the previous researches of western Chi-na,we obtained the evolution of PI anomaly during the period from Wenchuan MS8.0 earthquake to Sichuan Lushan MS7.0 earthquake.The results showed that obvious seismic hotspots appeared in the convergent region (29°-31°N, 101°-105°E)of the Xianshuihe,Longmenshan and An’ninghe faults from 2009 to 2010.These seismic hotspots shrank to the range of (29°-31°N,101°-103° E)during the years of 2011-2012 and disappeared after 2012,then the 2013 Lushan MS 7 .0 earthquake occurred.In another evaluation of the evolution of PI anomaly by using a different set of calculation parameters (with grid size of 1°× 1°and forecast window of 9 years),the results showed that there was a hotspot from 2009 to 2010 covering the southern Xinjin--Chengdu--Deyang fault,south-ern segment of Longquanshan western edge fault,Mabian--Yanjin fault,Ebian fault,and Tianquan--Yingjing fault (29°-30°N,103°-104°E).After 2011, this hotspot disappeared and the Lushan MS7.0 earthquake occurred in 2013. We also discussed the potential seismic risk in the studied area as well as the in-fluence of calculated parameters on the prediction efficiency.
Keywords：pattern informatics methodseismic hotspotLushan MS 7 .0 earth-quakeSichuan--Yunnan and its adj acent regions
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 780-789 )