Satellite Hyper-spectrum Information Of Gas Geochemistry Related To Earthquakes

Large earthquakes usually cause tremendous calamity to humankind. Earthquake monitor and studying is one of the most important ways to retrieve the geological disaster. Satellite remote sensing technology plays an important role on earthquake monitor and studying. With development of hyper-spectrum remote sensing technology, it is possible for us to obtain more new signals of geochemistry related to earthquake in recent years in order to study seismic activity and to predict the place where an impending earthquake will occur.Variations of CO total column and CO volume mixing ratio, CH4 and CO₂ volume mixing ratios, H₂O and O₃ total column with time in the areas around the epicenters of 12 May 2008 Wenchuan MS 8.0 earthquake, 4 April 2010 Baja California MW 7.2 earthquake in Mexico and 4 April 2010 MS 7.1 earthquake were extracted from satellite hyper-spectrum remote sensing data (AIRS). The geochemical variations of CO, H2O and earthquake activities were correlated.Those large earthquakes occurred in the different geographical regions. The gas geochemical information extracted from the data in the regions before, when and after the earthquake occurrences is characterized by the following:(1) CO total column in the area around the epicenter was well correlated to the Wenchuan MS 8.0 earthquake and the aftershocks.(2) CO total column increased to the value of 2⁴×1017mole/cm² higher than the corresponding mean values in 2008²009 about one month before the Baja California earthquake. CO total column and CO volume mixing ratio near-surface fluctuated, and their standard deviations of 8-day average enlarged and approached about 2 times as high as the non-seismic period before and after the earthquake.(3)Vapor total column after main event of Yushu earthquake was correspondingly higher than the average of two years before the earthquake occurrence. CO total column also increased before and after the earthquake. Brightness and surface temperature retrieved using MODIS L1B data associated with Yushu earthquake shows that the values of brightness and surface temperature were higher along the NW fault zones than in the un-faulted areas before the main shock. The higher values of surface temperature were larger than the corresponding daily mean values of ten years before, which is similar to the phenomena that measured values of air temperature before the Yushu earthquake were higher than the corresponding daily average of last ten years.Results indicated that the variations of gas geochemistry and temperature associated with the large earthquakes can be mainly attributed to the increasing leakage of gases from the lithosphere under the action of stress related to the earthquake and degassing along faults during earthquake generation. Additionally, electrochemical reactions in atmosphere caused by the earthquake may contribute to the geochemical variations. Our results indicate to retrieve the geochemical information of CO associated with earthquake using satellite hyper-spectral remote sensing data favors monitoring and prediction for earthquake.