was recorded Koyna earthquake by an of Deс. 10, 1967 of magnitude of about 7.0 (Richter scale) AR-240 accelerograph in 1A gallery of Koyna dam. Various investi- gators (4, 6) have computed maximum acceleration responše spectra, spectrum intensities etc. ration. for the earthquake, assuming that this accelerogram represents true ground accelethis earthquake, However, it is of great interest to know the true ground acceleration during Such an informationspecially when it has been recorded almost in its epicentral region. forces for aseismic would be of immense importance to study the nature of seismic design of structures in the epicentral region of similar earthquakes.