Relationship between the Earth tidal factor and phase lag of groundwater levels in confined aquifers and the Wenchuan M_s8.0 earthquake of 2008  

作　　者：SHI ZheMing WANG GuangCai 

机构地区：[1]School of Water Resources and Environment,China University of Geosciences [2]State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences

出　　处：《Science China Earth Sciences》2013年第10期1722-1730,共9页中国科学（地球科学英文版）

基　　金：supported by National Natural Science Foundation of China(Grant No.40930637);Special Project for Earthquake Science(Grant No.200808079);Subject Foundation of Ministry of Education for Doctor Candidates in Universities(Grant No.20100022110001)

摘　　要：This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland.These wells are also situated on several active fault zones and have exhibited considerable responses to the Wenchuan Ms8.0 earthquake of 2008 in China.We collected hourly records of water levels of these wells from 2007to 2009 and processed these data for analysis.The tidal factors,phase lags,and phase-difference changes of tidal residuals of each well were calculated.We found that when the Wenchuan quake happened,the tidal factors of the 4 wells were changing rapidly,while their phase lags and phase differences of tidal residuals declined swiftly,which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes. It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland. These wells are also situated on several active fault zones and have exhibited considerable respon- ses to the Wenchuan Ms8.0 earthquake of 2008 in China. We collected hourly records of water levels of these wells from 2007 to 2009 and processed these data for analysis. The tidal factors, phase lags, and phase-difference changes of tidal residuals of each well were calculated. We found that when the Wenchuan quake happened, the tidal factors of the 4 wells were changing rapidly, while their phase lags and phase differences of tidal residuals declined swiftly, which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.

关 键 词：tidal factor phase lag phase difference of tidal residual Wenchuan earthquake confined groundwater 

分 类 号：P641[天文地球—地质矿产勘探] P315[天文地球—地质学]