Geohazard activity intensity evaluation: theory, methods and practice

In order to research into the principle, methods and evaluation index system of geohazard activity intensity, this paper has briefly analyzed the major indexes and parameters which influence the earthquake activity intensity from two aspects, namely basic definition of earthquake activity intensity and quick evaluation. Referring to the earthquake magnitude classification, the maximum areal density was thus proposed to be the basis of geo-hazards activity intensity evaluation, therefore 8 levels of GHI (geohazard index) system has been set up. Two basic ways of quick areal density estimation are also put forward namely grid method and natural slope statistic method. In combination of practical case studies of geohazards triggered by the Wenchuan earthquake, geohazards triggered by the heavy rainfall in Ningshan County, Shaanxi in 2003, and geohazards of Baoji City, Shaanxi Province, remaining problems of evaluation index system, maximum areal density estimation and other representative aspects are also discussed, it′s also emphasized that GHI leveling is still at its early stage, which requires for further improvements during pratices.