The 7.2 magnitude earthquake, November 1975, Island of Hawaii

Abstract

The largest earthquake in over a century struck Hawaii the morning of November 29, 1975, at 4:48 AM HST. The earthquake was of magnitude 7.2 on the Richter scale. It was centered about 5 km beneath the Kalapana area on the southeastern coast of Hawaii, the largest island of the Hawaiian chain (Fig. 1) and was preceded by numerous foreshocks. The event was accompanied, or followed shortly, by a tsunami, large-scale ground movemtns, hundreds of aftershocks, an eruption in the summit caldera of Kilauea Volcano. The earthquake and the tsunami it generated produced about 4.1 million dollars in property damage, and the tsumani caused two deaths. Although we have some preliminary findings about the cause and effects of the earthquake, detailed scientific investigations will take many more months to complete. This article is condensed from a recent preliminary report (Tillings an others 1976)