ESTIMATION OF THE EARTHQUAKE INTENSITIES IN IRAN BASED ON GROUND EFFECTS (APPLICATION OF INQUA SCALE); 2 CASE STUDIES

The main criteria of so-called macroseismic intensity repose on the manner in which earthquake vibrations affect human beings and civil structures, as well as damage incurred by man-made structures which are strongly depended on the existence of human and/or the man-made objects and also depend on local economy and cultural setting. However, INQUA is a new scale evaluating earthquake entensity from the sole evidence inscribed in the environment itself such as fractures, collapses, landslides and rock-falls. The new insights available today into the response of the physical environment to seismicity can lead to intensity evaluations which are better description of the real strength of the causative earthquake. In this study, INQUA scale is introduced and applied for the first time in Iran to evaluate Bam (December, 2003) and Firuzabad, Kojur (May, 2004) earthquakes. Both of these earthquakes happened in places where the ground effects of earthquake were noticeable. (Bam is placed in the border of Southeastern Lut Desert of Iran and Firuzabad epicenter was located in a mountainous area in Central Alborz of Iran). The macroseismic intensity and isoseismal map of both earthquakes were prepared in INQUA scale. The epicentral intensity was at IX level for Bam earthquakes and VIII in case of Firuzabad which were conform to the EMS-985 intensity estimation.