Earthquake that rattled Big Island unrelated to volcanic activity, scientists say

KAILUA-KONA — The magnitude-5.3 temblor that struck Saturday evening just east of Kalaoa was unrelated to volcanic activity, scientists say.

“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, Hawaiian Volcano 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.”

The earthquake, recorded at 5:09 p.m. Saturday, was located about 12 miles east of Kalaoa at a depth of about 8 miles, according to HVO. It jolted the island, triggering rockfalls along highways 19 and 11, as well as a slip of the pali at Kealakekua Bay.

Three aftershocks were recorded within an hour of the earthquake, including a magnitude-3.0 event approximately 11 minutes following the mainshock. Through Monday afternoon, 15 aftershocks were recorded.

Light to strong shaking, with a maximum Intensity of VI on the Mercalli Intensity Scale in the area of Waikoloa, was reported across the Big Island and as far away as Oahu. The U.S. Geological Survey estimated shaking up to Intensity VII in the immediate vicinity of the epicenter.

The USGS “Did you feel it?” service received over 1,000 felt reports within the first hour of the earthquake, according to HVO. By Monday, that number topped 1,900.

Shiro said the earthquake caused no detectable changes in activity at Kilauea and Mauna Loa volcanoes, according to HVO. No tsunami was triggered.


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