Seismic Anomaly Detection And Analysis Research Based On Multi-sensor Satellite Data

Earthquake is one of the most unexpected,destructive and hazardous disasters on the Earth.It broke out frequently since the beginning of this century,especially for medium-to-large earthquake,causing serious hazards to people and resulting in great loss on people's property.Earthquake detecting,predicting and warning is the major issues of seismology research.With the development of remote sensing technology and data assimilation techniques,the massive remote sensing data and assimilating data provide long-term,spatio-temporal continuous parameters in surface,atmosphere and ionosphere,as well as more reference and basis for earthquake anomaly monitoring and warning.In this paper,based on the coupling model of the "Lithosphere-CoversphereAtmosphere",this study use the Chile earthquake which broke out on February 27,2010,as a study case.Combining multiple parameters of surface and ionosphere,such as remote sensing data and assimilate data,we take different method to detect and analyze different parameters' anomalies before and after earthquake.Compared with standard deviation method,this research attempted to apply continuous wavelet transform(CWT)method to detect the abnormal characteristic in frequency and scale of surface latent heat flux parameter and also verified the validity of this method.In order to analyze the electromagnetic parameters' distribution information in frequency and scale and the correlation of different parameters,this paper first adopt the sliding correlation analysis and wavelet multi-scale decomposition method,combining with time-frequency analysis and CWT method.In addition,in order to remove the influence of solar activity,the season and the climate when detecting SKT anomalies,we extract the eighth order low frequency of the residual between raw observations and seventh order low frequency and calculated the K value.Finally,by comparing the results of different data processing methods,the evolution of characteristics in time,frequency and the different parameters' correlation,this paper analyzes the possible reason of geologic tectonic environment of the study area,explains the abnormal phenomenon and then provides the basis and reference for the study of earthquake warning methods.The experimental conclusions are as follows:1.Verified the validity of CWT and sliding correlation method in SLHF and plasma correlation analyzing.Standard deviation method,one-dimensional continuous wavelet transform and time-frequency joint analysis method can effectively detect the singularity and abrupt point of the seismic signal and also the energy anomaly at different scales and frequencies.Using sliding correlation analysis method,the study find out the decline tend of correlation between different parameters before the earthquake.2.The abnormal test results present different with the study areas' size.In the study area of 5 °,10 °,20 ° and 30 ° from the epicenter,the anomalies in different study areas were analyzed,and it is found that significant anomalies information could be detected in the study area from 5 ° to 20 ° from the epicenter.In the range of 30 °,the abnormality is not obvious.3.Several different parameters appeared anomalies before Chile earthquake.The results show that the anomaly information of different parameters of multi-source satellite data before strong earthquakes can be detected by different detection methods.The electron density,temperature,ion density and O+ density are abnormally increasing,and the electron temperature is abnormally decreasing.The correlation between O+ and He+,H+ and O+ is declining before the earthquake.4.SLHF and electromagnetic anomalies are different in frequency and scale distribution.By comparing the differences in the frequency and scale of the multiparameter anomalies,it is found that the surface latent heat flux anomalies are mainly distributed in the middle-to-low scale or middle-to-high frequency area.The anomalies of the electromagnetic parameters are generally distributed in the middle-to-high scale or middle-to-low frequency parts.5.Land and sea differences of SLHF anomalies and their relationship with plate tectonics.By analyzing the temporal and spatial distribution of SLHF before and after the earthquake,it is found that the flux in area of sea is generally higher than that of the land area,and the anomaly is mostly in the marine area.2-3 days after the earthquake,there are still high anomalies.In addition,the anomaly mainly distributes at the junction of the Nazca plate,the Antarctic plate and the South American plate.6.Skin temperature's "cold anomaly" phenomenon occurs before earthquake.Based on wavelet multi-scale decomposition,the eighth order low frequency of the residual is calculated.It is found that the SKT value decreases in the southern tip of South America plate before the earthquake.