A Novel Approach for Estimating Debris Flow Velocities from Near-Field Broadband Seismic Observations  

作　　者：YU Dan LI Zhengyuan HUANG Xinghui FAN Junyi XU Qiang 

机构地区：[1]China Earthquake Networks Center,Beijing 100045,China [2]State Key Laboratory of Geohazard Prevention and Geo-environment Protection,Chengdu University of Technology,Chengdu 610059,China

出　　处：《Earthquake Research in China》2020年第3期418-429,共12页中国地震研究（英文版）

基　　金：sponsored by the 973 Program(2013CB733206);the 863 Program(2012AA121300)。

摘　　要：On August 7^(th),2010,Sanyanyu and Luojiayu debris flows triggered by a heavy rain have lashed Zhouqu City around midnight,leading to catastrophic destruction which killed 1765 people and resulted in enormous economic loss.The ZHQ Seismic Station is located approximately 170 m west of the outlet of the Sanyanyu Gully.The seismometer deployed at the seismic station started recording seismic signals of ever-enlarging amplitude around 10 minutes before the debris flow rushed out of the Sanyanyu Gully,showing ever approaching seismic source,i.e.the debris flow.In this study,we analyze this seismic event and propose an inversion algorithm to estimate the velocity of the debris flow by searching the best-fitting pairs of envelopes in the synthetic seismograms and the corresponding field seismic records in a least-square sense.Inversion results reveal that,before rushing out of the outlet,the average velocity of the debris flow gradually increased from 6.2 m/s to 7.1 m/s and finally reached 15 m/s at approximately 0.5 km above the outlet and kept this value since then.Obviously,the ever-increasing velocity of the debris flow is the key factor for the following disasters.Compared with other studies,our approach can provide the velocity distribution for the debris flow before its outbreak;Besides,it has the potential to provide technological support for a better understanding of the disaster process of a debris flow.

关 键 词：Sanyanyu debris flow Broadband seismic signals INVERSION Debris flow velocities 

分 类 号：P642.23[天文地球—工程地质学]