IRAN STRONG MOTION NETWORK (ISMN) PROSPECTS AND ACHIEVEMENTS

Iran is one of the most seismically active countries with historical destructive earthquakes running dwelling, inducing casualties and taking lives. A review of the seismic history of Iran shows that this country is located in a high seismically active region, which covers the most parts of Iran. The earthquake hazard in Iran has created requirement for better understanding of seismic phenomenon and earthquake impacts on buildings. This had led to increase the research activities in geophysics, engineering seismology and earthquake engineering. One of the fundamental needs to earthquake engineering is the information and data about ground motion. For a safe seismic design, the earthquake ground motion data is required for the dynamic analysis of the structures. Iran strong motion network (ISMN) established for providing such data collection. ISMN has started its activities since 1973. At the end of 1992, this network was consisted of 274 analog accelerographs and grown up rapidly. At present time (January 2007) it consists of 1071 digital (SSA-2), and 28 analog (SMA-1) accelerographs. Most of the accelerograph units are concentrated in seismically active or in densely populated and industrialized areas. Since the installation of the first station, about 6260 accelerograms are recorded by this network. Among these, the maximum peak acceleration, which is about 1g (V component), is due to Bam earthquake (26 December 2003) that is recorded at Bam station, and Zanjiran earthquake (20 June 1994). The major number of accelerographs (88) has been installed in Fars province and 900 accelerograms obtained in this province up to now. The programs of Building and Housing Research Center (BHRC) for developing of ISMN In the next 5 years are, installation 250 new accelerographs in seismicity active area, monitoring another 20 structure, 80 dams, 20 power plant, bridge and life line, time synchronization for all accelerographs, and 100 satellite communication equipments.

Keywords:

Iran strong motion network (ISMN) , time synchronization , accelerographs