Scientists Say Hawaiʻi Earthquake Unrelated To Volcano

Apr 16, 2019

Map of the 5.3 magnitude earthquake on Saturday, April 15, 2019
Credit Hawaii Volcano Observatory / USGS

KALAOA, Hawaii — A weekend earthquake that struck Hawaiʻi was not related to volcanic activity, scientists said.

The 5.3-magnitude earthquake Saturday was not caused by magma moving underground, Researchers at the Hawaiian Volcano Observatory said.

The quake around 5 p.m. about 8.7 miles (14 kilometers) northwest of Kalaoa was due to movement of the crust under the Big Island, scientists said.

The earthquake caused no detectable changes in activity at Kīlauea and Mauna Loa volcanoes and a tsunami was not triggered, according to the observatory.

The quake was located at a depth of about 9.3 miles (15 kilometers), 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 Oʻahu.

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 Hawaiʻi observatory said.