Satellite monitoring of atmospheric methane concentration and its potential use in earthquake prediction and energy resources exploration

The abnormal increase of the ground temperature in seismic areas is one generally observed phenomenon prior to earthquakes, and it can be monitored by using satellite thermal infrared window channel and has been used as a kind of imminent precursor in earthquake prediction. Additionally, a successful test on searching petroleum enrichment zone by using such phenomenon detected with satellite thermal infrared window channel was carried out. The other phenomenon observed before earthquakes is the significant increases of concentrations of various gases in the atmosphere, such as CO/sub 2/, CH/sub 4/, and so on, due to large quantity of gases escaped from the crust in seismic areas, particularly, when the seismic areas are located in oil and natural gas enrichment places. In 1991 in the Chinese capital territory (38.5 N-41.0 N, 113.0 E-120 E) there were four earthquakes with magnitudes of M 3.8 to M 5.1. The observational data shown that the CH/sub 4/ concentrations in the surface atmosphere could be about 0.7 to 5 times higher than the normal value of 1.7 ppmv in Beijing several days to more than ten days before these earthquakes. So that the significant increase of atmospheric methane concentration in seismic areas may also be considered as a kind of earthquake precursor. Methane is an infrared absorbing gas, its concentration variation may cause changes of outgoing radiances at the top of the atmosphere, hence, it may also be possible to monitor such phenomenon from satellite with some properly selected channels and used as an possible precursor in earthquake prediction.