NAʻALEHU – A magnitude-4.5 earthquake located in the Kaʻū District shook the Island of Hawaii on Saturday, May 9, at 2:18 a.m., HST.
The quake was centered 5 miles north of Naʻalehu at a depth of 6 miles, according to Wes Thelen, the Seismic Network Manager for the USGS Hawaiian Volcano Observatory. There were three aftershocks (magnitudes 1.6, 1.5, 1.4) of the earthquake were recorded as of 3:30 a.m., HST. Scientists say additional aftershocks are possible and could be felt.
Over 70 reports claimed to feel the earthquake within an hour of the event. Light shaking has been reported across the island. At these shaking intensities (Intensity IV), damage to buildings or structures is not expected, scientists said.
Over the past 30 years, the area north of Nāʻālehu has experienced 6 earthquakes, including today’s event, with magnitudes greater than 4.0 and at depths of 5–13 km (3.1–8.1 mi). This area of Kaʻū is a seismically active region where a magnitude-6.2 earthquake occurred in 1919. Areas adjacent to this morning’s event experienced earthquakes of magnitudes 6.0, 7.1, and 7.9 in 1868.
The depth, location, and recorded seismic waves of today’s earthquake suggest a source on the large fault plane between the old ocean floor and overlying volcanic crust, a common source for earthquakes in this area. USGS Hawaiian Volcano Observatory
The earthquake caused no detectable changes in Kīlauea Volcano’s ongoing eruptions, on Mauna Loa, or at other active volcanoes on the Island of Hawaiʻi, says USGS. A magnitude-3.1 earthquake that occurred in Kīlauea Caldera about one minute before the magnitude-4.5 earthquake was unrelated to the Naʻalehu event.
The Big Island has been experiencing elevated seismicity beneath Kīlauea’s summit and upper East and Southwest Rift Zones the past few weeks.