KALAOA, Hawaii — A weekend earthquake that struck Hawaii was not related to volcanic activity, researchers at the Hawaiian Volcano Observatory said.
The scientists believe that the 5.3-magnitude earthquake, happening around 5 p.m. Saturday about 8.7 miles northwest of Kalaoa, was not caused by magma moving underground but was due to movement of the crust under the Big Island.
The earthquake caused no detectable changes in activity at Kilauea and Mauna Loa volcanoes and a tsunami was not triggered. The quake was located at a depth of about 9.3 miles, which is far deeper than a quake that might be caused by moving magma, according to an observatory official.
“Although the earthquake occurred under the east margin of Hualalai volcano, there is no indication at this time that the event is related to volcanic activity,” said geophysicist Brian Shiro, the observatory’s seismic network manager. “The location and depth of this event suggest it is likely related to flexure or settling of the crust beneath the weight of the island.”
More than 1,000 reports were sent to the U.S. Geological Survey’s “Did you feel it?” service, with residents filing reports across the Big Island, from Hilo in the east to Kailua-Kona in the west, and as far away as Oahu.
Three aftershocks were recorded within an hour of the earthquake, including a magnitude-3.0 event about 11 minutes after the initial quake. Through Monday afternoon, 15 aftershocks were recorded, the Hawaii observatory said.