عبادلله قنبری - دانشیار دانشکده مهندسی عمران دانشگاه تبریز

The town of Bam with geographical coordinates of about 59o in eastern length and 28-29o latitude lies east south of Iran. Its distance to the border of Pakistan is about 370 km and to Tehran is about 6o, 51_ and 11__ and its height from high seas is 1050 m. Bam devastating earthquake with the magnitude of 6.5 degree on the scale of Richter which occurred on December 26 2003 caused killing of about 28000 people, wounding of 25000 persons. It made the rest 90 percent of residents in the town and its suburbs homeless, collapsing and devastating 85-90 percent of urban buildings and structures. The region of Bam is located between two large tectonic Lut depression at the north and Jazmourian depression at the south. Two main tectonic elements of Lut block and the zone of flysch extends to out of central Lut and includes the main part of eastern state of Iran. The block of Lut which Bam town resides in its western edge is an extended part with northern extension surrounded with different unstable faults which faults are often at the raw of seismic faults. Lut block extends to the more than 800 km from Jazmourian depression at the south to the region of Gonabad in Khorasan at the north. The average width of it in the central part and south is about 200-250 Km. Its western border is performed by an extended and main fault called Nayband. If we study the movement and action of Nyband fault, it is observed that it has experienced the segmentation of strike – slip fault, and faulting series of 1978-2004 is one of the most obvious type of segmentation which is observable on the ground and any segment of it has been activated at one time and this activity has been accomplished from north to the south, i.e. from Tabas city towards the country of Nayband (Nayband seismic fault is nominated through the same country) and from Nayband towards Shahdad and from there towards Bam.