Maximum Expected Magnitude Assessment in a Geo Computer Environment: Case Study

Different approaches to seismic hazard assessment are compared. Each of them could be applied more or less successfully for territories which are stable in time and have a high level of seismic activity. A long-term seismic catalogue, not only including historical but also paleoearthquake data, is an essential requirement. But, in practice, such an ideal situation is very rare. Initial data is usually poor and short-term. Seismic hazard assessment could be more complicated for regions which are transient between relatively stable platforms and active mountain massifs. A new step in geoinformation technology for seismic hazard assessment based on a GEO computer environment is presented, its application is illustrated by the real case hazard evaluation for the territory of the Stavropol region, which is situated between the Russian platform and the Great Caucasus. The regional catalogue covers a time period of about 150 years. Though the region under consideration is not large, seismic activity is variable in space, from almost aseismic zones to rather active areas. GEO allows us to incorporate different techniques and all available information in the analysis, including those which are very difficult to formalize. The space distribution of the maximum expected earthquake magnitude is determined as a function of geological and geophysical data. An important feature of GEO is that it makes it possible to control the result of complicated algorithms through some relatively simple physical reasons.