Depth estimates of large earthquakes on the island of Hawaii since 1940.

Abstract

Although hypocenters of earthquakes on the island of Hawaii are now routinely assigned to within 5km, depth was a poorly determined parameter until the early 1960's. However, the 1950-1960 period was very active both in volcanic eruptions and large earthquakes. Source depths for the 12 largest Hawaiian earthquakes (magnitude 6 or greater) since 1940 are estimated from the ratios of body and surface wave amplitudes recorded at Pasadena, California. In general, large earthquakes near the volcanic flanks and fault systems are shallow (= or < 20km). Two earthquakes of magnitude 6 occurred under the volcanoes Mauna Loa (in 1950) and Kilauea (in 1951); they preceded major eruptions by 3 days and 14 months, respectively, and had the largest depth estimates at 40-55km and 35-50km. -from Authors