I.D Gupta - Central Water and Power Research Station, Pune (India)
V R.ambabu - Central Water and Power Research Station, Pune (India)
R.G Joshi - Central Water and Power Research Station, Pune (India)

Using strong-motion data recorded at small hypocentral discances in Koyna darn area, preliminary empirical scaling relations have been developed for evaluating peak acceleration, velocity and displacement due to given earthquake magnitude and distance. A set of nineteen three-component accelerograms corrected for instrument response and base line distortions is used for this purpose. Probability distribution of observed data abour the mean trends fitted by least square regression analysis is also studied to consider the scattering in the observed data. The presented results will provide a useful basis for evalating peak amplitudes with a specified level of risk to define .esign earthquake forces in areas with Koyna tyke geological setuc