利用概率密度分布提取流体观测资料中的高频异常信息——以2008年汶川8.0级地震为例

Extracting high-frequency anomaly information from fluid observational data:a case study of the Wenchuan M_S8.0 earthquake of 2008

随着地下流体观测技术的提高,尤其是地下流体观测数字化改造以后,观测资料的采样频率明显提高,这些高频采样的观测资料中蕴含着丰富的构造信息,如何从分钟值甚至更高频率采样的观测资料中提取有用的异常信息,是目前从事地震地下流体资料分析人员最为关注的科学问题之一.本文引入概率密度分布法,分析了2008年汶川8.0级地震前南北地震带及其附近区域72个测点的数字化水位和水温分钟值采样高频观测资料,结果显示:汶川8.0级地震前有16个测点水位和14个测点水温出现高频异常信息,出现高频信息异常的观测点多集中在滇西南构造带,异常出现的时间呈现出由南向北推移的特征.据此认为概率密度分布法在流体资料的高频异常信息提取方面具有一定的可靠性与适用性,可为数字化高频观测资料异常提取提供借鉴.

With improvement of underground fluid observation technology,the sampling frequency of data has been obviously improved,especially after the digital transformation.There is a great deal of tectonic information in high-frequency observational data.It is a key problem how to extract the useful high-frequency information from theses data.We introduced the PDF（probability density distribution）method,and analyzed the observed fluid data of water level and water temperature at 72 stations in the area of the north-south seismic zone before the Wenchuan MS8.0earthquake on 12 May,2008.The analysis results show that 16 water level and 14 watertemperature data had the high-frequency anomalies before the MS8.0earthquake,and the points with abnormal information were concentrated in the tectonic belts of southwest Yunnan.The high-frequency anomalies appeared from south to north over time.On the basis of these results we considered that the PDF method has certain reliability and applicability to extract the highfrequency anomaly information from observational data of fluid.It can provide a reference for information extraction of high-frequency digital observation.