重力固体潮信号独立成分的谱相关解调与地震前兆信息提取  

Cyclic spectrum demodulation of independent composition of gravity tide signals and extraction of seismic precursor information

作　　者：高略 全海燕[1] GAO Lue;QUAN Hai-yan(Faculty of Information and Automation, Kunrning University of Science and Technology＇, Kunming 650500, Chin)

机构地区：[1]昆明理工大学信息工程与自动化学院,昆明650500

出　　处：《地球物理学进展》2018年第3期916-922,共7页Progress in Geophysics

基　　金：国家自然科学基金项目(41364002)资助

摘　　要：重力固体潮信号是一种多谐波的混合信号,为了提取其中所包含的地震前兆异常信息.本文结合重力固体潮的产生机制,建立了一种重力固体潮正交分解模型.在此基础上,利用独立分量分析算法实现重力固体潮信号的加性分解,然后针对独立分量中的调制关系,利用谱相关方法对其进行乘性解调.从而,完整地提取出了重力固体潮信号中丰富的潮汐谐波信息.进一步,引入理论计算值作为实际测量值的参考背景,在独立分量中凸显出原重力固体潮信号中的异常变化特征.通过对云南地区的实际震例研究表明,重力固体潮独立分量的异常特征与地震事件的时序存在密切的相关性.在地震发生前的1~5个月内,对应于重力固体潮信号长周期谐波系的独立分量在时域波形和循环相关谱方面均有明显的异常变化,而且普遍存在,充分反映了这一异常变化与地震前地壳内部能量的变化有关,很有可能就是重力固体潮信号中隐含的地震前兆信息.The gravity earth tide signal is a mixed harmonic signal.In order to extract the anomaly information of earthquake precursor contained in it. In this paper,an orthogonal decomposition model of tidal force is established according to the relationship between the moon and the sun relative to the earth＇s position. On this basis,the Independent Component Analysis（ ICA） algorithm is used to decompose the gravity tide signal to realize the orthogonal decomposition of the model. Then the cyclic spectrum method is used to multiplicative demodulation the signal. It can extract the tidal harmonic information in the gravity tide signal. Then,we use the corresponding theoretical value as a reference in the course of earthquakes analysis. The results show that the case study of Yunnan area,the phase of gravity solid tide and timing of seismic events are closely associated. During the period of 2 ~ 3 months before the earthquake,the long period harmonic component of the gravity tide signal will change obviously. This fully reflects the change of energy in the crust before the earthquake. In this work,it is proved that the gravity tide is of great significance in the earthquake triggering.

关 键 词：重力固体潮 正交分解模型 独立分量分析(ICA) 谱相关 地震前兆信息 

分 类 号：P312[天文地球—固体地球物理学]