3.9 Magnitude Earthquake Strikes Near Pāhala, Linked to Ongoing Seismic Swarm

More than 50 Ka'ū residents reported feeling the ground move within 30 minutes of a 3.9 magnitude earthquake that struck Sunday morning about 2 miles east-northeast of Pāhala, the latest jolt from a seismic swarm that scientists have called unlike anything previously recorded in Hawai'i.

The U.S. Geological Survey logged the quake at 11:41 a.m. HST at a depth of approximately 2 miles below sea level. No damage or injuries were reported, and the Hawaiian Volcano Observatory confirmed the event produced no apparent changes at either Mauna Loa or Kīlauea. USGS noted that aftershocks remain possible in the coming days to weeks.

The earthquake is tied to an ongoing swarm beneath the Pāhala area that has been active since August 2019. HVO scientists have tracked swarm activity to earthquakes occurring beneath Kīlauea's lower Southwest Rift Zone, under the town and extending roughly 6 miles offshore, at depths between 15 and 25 miles. The mechanism driving the swarm is posited to be deep magma pathways running beneath the island.

A USGS Volcano Watch article described the activity as "a unique occurrence that has not previously been observed in Hawai'i," even as earthquake records from the Pāhala region stretch back to the 1960s. The swarm has drawn sustained scientific scrutiny since it began, becoming one of the most closely watched seismic sequences on the island.

Sunday's quake follows a run of significant events in the sequence: a magnitude-5.8 in February 2024, a magnitude-4.8 in November 2024, and a magnitude-4.3 in December 2024 that was felt not only across the Big Island but also in Honolulu and Kailua on O'ahu, more than 200 miles from Pāhala.

Pāhala, a former sugar plantation community, is the largest town in the Ka'ū District with a population of 1,403 according to the 2020 Census, situated approximately 23 miles southwest of Hawai'i Volcanoes National Park. The park is home to HVO, where Scientist-in-Charge Ken Hon leads continuous monitoring of both the swarm and volcanic activity across the state.