6.0 quake jolts west Hawaii, closes roads overnight

A magnitude-6.0 earthquake rattled West Hawaii late Friday, shutting down stretches of Highway 11, Nāpōopoo Road and Milolii Road overnight as rockslides and debris forced police to keep motorists away until crews could clear the roadway.

The quake struck at 9:46 p.m. HST on Friday, May 22, about 7 miles south of Hōnaunau-Nāpōopoo and 14 miles below sea level. The U.S. Geological Survey and the Hawaiian Volcano Observatory said the shaking reached Modified Mercalli intensity VII, or very strong shaking, with light to moderate damage possible across the west side of the island.

Residents from South Kona to Keauhou reported items falling from shelves, cracked walls and other damage inside homes and businesses. More than 2,662 felt reports came in within the first hour, and more than 2,500 residents and visitors submitted reports overall, giving emergency officials a detailed picture of how far the shaking spread.

By about 6:30 a.m. Saturday, all roads had reopened, though the County of Hawaii said debris piles could remain along the roadside until they were fully removed. The county and Big Island Police had earlier closed the affected stretches to keep drivers away from unstable rock and mud.

Power service also took a hit. Hawaiian Electric said about 70 of the roughly 1,000 customers affected by the earthquake were still without electricity at 10 a.m. Saturday, while about 20 customers in Keauhou were out because of a separate vehicle accident. The utility warned that downed power lines should be treated as energized and dangerous, and said people should stay at least 30 feet away.

Mayor Kimo Alameda said Kona Community Hospital reported only minor damage and no interruption to service. He also said KTA Super Stores in Keauhou had merchandise knocked to the floor but opened as usual. County officials urged residents and businesses to report damage so Civil Defense can identify priorities if state or federal disaster aid becomes available, and they reminded people to use caution around gas and power lines while checking their property.

The Hawaiian Volcano Observatory said the quake was not tied directly to volcanic activity and had no apparent impact on Mauna Loa or Kīlauea. It was caused instead by stress from bending of the oceanic plate under the weight of the Hawaiian Islands. Several aftershocks, most smaller than magnitude 3, had already followed, and more could come in the days ahead. USGS said the event fit a region that has seen 36 other magnitude-5-or-greater quakes within 100 kilometers over the last 50 years, including the 1975 Kalapana earthquake and the 2006 Kīholo Bay earthquake.