FORK (SOUTH EAST OF DARAB, IRAN) EARTHQUAKE OF NOVEMBER ۶, ۱۹۹۰ A PRELIMINARY FIELD STUDY AND DOCUMENTATION

The Fork earthquake of magnitude Ms=۶.۶, Mb=۶.۲ occurred on November ۶, ۱۹۹۰ in the mountains about ۳۳۰ Km Southeast of Shiraz--south of Iran. It killed ۲۲ people, injured ۱۰۰ and caused widespread geotechnical and structural damages to several villages covering an approximate area of ۹۰۰ square Kilometers. Three hundred residence were totally destroyed, While ۲۰۰۰ houses were received damages ranging from ۳۰ to ۷۰ percent. The maximum intensity of the main shock just exceeded VI (MMI). The earthquake provided no evidence of surface faulting. A foreshock, approximately ۱۰-۲۰ seconds before the main destructive shock, gave an early warning and enough time for many people to run outdoors and save their lives. This seems to be the reason for the relatively low number of casualties. It seems that the Fork earthquake was another "Subsedimentary Zagros-Type Earthquake' case in the Zagros Active Folded Belt. This parer summarizes the macroseismic evidence of the Fork earthquake and discusses geotechnical and structural failures suffered in this earthquake