Early warning of geohazards using space technology

The societal impact of geological hazards is enormous. Every year volcanoes, earthquakes, landslides and subsidence claim thousands of lives, injure many thousands more, devastate peoples' homes and destroy their livelihoods. The costs of damaged infrastructure are taken higher still by insurance premiums and run into the billions in any currency. This affects rich and poor alike, but with a disproportionate impact on the developing world. As the human population increases and more people live in hazardous areas, this impact grows unsustainably. It must be reduced and that requires increased understanding of the geohazards, improved preparedness for disasters and better ways to manage them when they occur. The inter-related disasters that comprise geohazards are all driven directly by geological processes and share ground deformation as a common thread. This means that they can be addressed using similar technology and understood using related scientific modelling processes. Geohazards are a complex phenomenon and no one method can provide all the necessary information and understanding. It is essential that Earth Observation data are integrated with airborne data, in-situ observations and associated historical data archives, and then analysed using GIS and other modelling tools if these hazards are to be understood and managed. Geohazards occur in one form or another in every country. They do not respect national boundaries and have the potential to cause changes in the atmosphere that will be truly global in effect, requiring a global observing infrastructure to monitor them. The current situation in space research of early warning of geohazards indicates a few phenomena, related with geohazard processes: Earth's deformation, surface temperature, gas and aerosol emission, electromagnetic disturbances in ionosphere. Both horizontal and vertical deformations scaled about tens centimetres and meters measured after the shock. Such deformations are recorded by InSAR technique with confidence. Pre-earthquake deformation are rather small - centimetres. A few cases of deformation mapping after the shock using satellite data are known at present time. Volcanoes, landslides and subsidence indicate clear deformations in centimetre scale before the event. Future development lays in precision SAR systems with medium spatial resolution and combination with GPS technique. Temperature growth is one of the reliable signs of preparing volcano eruption. A few current operational systems using geostationary and polar satellites for volcano monitoring are on duty. There are numerous observations of surface and near surface temperature growth on 3-5 Ñ prior to Earth's crust earthquakes. Modern IR satellite systems simply record such thermal anomalies. Methods of earthquake predictions are developing using thermal IR survey. Gas emission before the eruption is well-known phenomena. A few cases of gas and aerosol content change in atmosphere before the earthquake were described. Satellite methods allow to restore the concentrations of gases in atmosphere: O3, CH4, CO2, CO, H2S, SO2, HCl and aerosol. However the spatial resolution and sensitivity of modern systems are still low. First promising results were obtained only for ozone. Electromagnetic researches of ionosphere in relation with earthquake are widely spread now. Stable statistical estimations of ionosphere-lithosphere relation were obtained. A few new ionospheric satellites are prepared for launch. Other auxiliary space technologies are developed: oxygen luminescence, unusual clouds, atmosphere sounding. Thus, we can declarate the need of Integrated Global Observation Strategy for Geohazards - IGOS-Geohazard. Such initiative is developed now under UNESCO patronage.