THE 1990 BOHOL EARTHQUAKE: TSUNAMI OBSERVATIONS AND EFFECTS AT BOHOL ISLAND, PHILIPPINES

The earthquake of February 8, 1990 offshore the Island of Bohol in the Central Philippines was a tsunamigenic event caused by crustal displacements along an unknown northeast-southwest trending fault. Isoseismal distribution confirmed such orientation with higher seismic intensities at the southeastern areas of Bohol Island. Subsequent field surveys, interviews with eyewitnesses and measurements of runup heights, support that significant tsunami inundation occurred along the southeastern coast of the island. Based on this investigation and review of historical data, we conclude that the source region of the 1990 tsunami was along an unknown offshore submarine structure.