4.0 Earthquake Part of Ongoing “Seismic Swarm” in Pāhala
A 4.0 magnitude (preliminary 4.4) earthquake reported at around 6:15 p.m. on Thursday, Jan. 14, is linked to a seismic swarm which started in August 2019, according to scientists with the US Geological Survey’s Hawaiian Volcano Observatory.
The Pacific Tsunami Warning Center reported that no tsunami was expected. The USGS “Did you feel it?” service received over 580 “felt” reports within the first hour of the earthquake.
HVO acting Scientist-in-Charge, David Phillips said the earthquake had no observable impact on the ongoing eruption at Kīlauea’s summit at the time an information statement was released (around 8 p.m.) on Thursday evening.
“This earthquake is part of the ongoing seismic swarm under the Pāhala area, which started in August 2019. Unlike most events associated with this swarm, this earthquake was widely felt across the Island of Hawai‘i, and as far away as Oʻahu,” said Phillips.
The HVO continues to monitor Hawaiian volcanoes for any changes.
According to the HVO, the quake was located beneath the south part of the Island of Hawai‘i, in the district of Kaʻū, and was centered about 5 miles northeast of Pāhala, at a depth of 21 miles.
Earthquakes beneath Kīlauea’s lower Southwest Rift Zone occur mostly at depths of 15-25 miles, beneath the town of Pāhala and extend about 6 miles offshore, according to the information statement.
“Earthquakes in this region have been observed at least as far back as the 1960s and are posited to be related to deep magma pathways under the island,” the HVO reports.
Moderate shaking, with maximum Intensity of V on the Modified Mercalli Intensity Scale, has been reported across parts of the Island of Hawai‘i. At that intensity, significant damage to buildings or structures was not expected.