Remote sensing and earthquakes: A review

The current situation in earthquake space research indicates a few phenomena related with earthquakes: Earth’s deformation, surface temperature growth, gas and aerosol exhalation, electromagnetic disturbances in the ionosphere. Both horizontal and vertical deformations scaled about tens centimetres and meters were measured after the earthquake events. Radar satellites using InSAR technique record such deformations with confidence. Pre-earthquake deformations are rather small – centimetres. A few cases of deformation mapping before and after the earthquake using satellite data are known at present time. Numerous observations have indicated an increase in surface and near-surface temperature of the order of 3–5 °C prior to earthquakes. Modern IR satellite sensors simply record such thermal anomalies. A few cases of gas and aerosol content change before the earthquake are also known. Remote sensing technologies allow us to retrieve the concentrations of gases in the atmosphere: O3, CH4, CO2, CO, H2S, SO2, HCl and aerosol. However the spatial resolution and sensitivity of modern sensors are still low. First promising results were obtained only for ozone, aerosol and humidity. Electromagnetic researches of ionosphere in relation with earthquakes are widely spread now. Stable statistical estimations of ionosphere-lithosphere relation were obtained, and a few new ionospheric satellites were launched recently.