ATTENUATION RELATIONS FOR STRONG SEISMIC GROUND MOTION IN THE HIMALAYAN REGION

Strong motion data from various regions of India have been used to stu dy attenuation characteristics of horizontal peak acceleration and vel ocity. The strong ground motion data base considered in the present wo rk consists of various earthquakes recorded in the northern part of In dia since 1986 with magnitudes 5.7 to 7.2. Using these data, relations for horizontal peak acceleration and velocity, which are log(10)a = 1 .14 +/- 0.31M + 0.65 log(10) R log(10) v = 0.571 + 0.41M + 0.768 log(1 0) R have been proposed where a is the peak horizontal acceleration in cm/sec(2), v is the peak horizontal velocity in mm/sec, M is body wav e magnitude, and R is the hypocentral distance in km. The proposed rel ations are in reasonable agreement with the small amount of strong gro und motion data available for the northern part of India. The present results will be useful in estimating strong ground motion parameters a nd in the earthquake resistant design in the Himalayan region.