No Tsunami After 4+ Earthquake at Mauna Loa Summit

There is no tsunami threat to Hawaiʻi after a preliminary magnitude 4.1 earthquake reported at 4:26 a.m. on Tuesday, Sept. 6, 2016 in the summit region of the Mauna Loa Volcano on Hawaiʻi Island, according to the Pacific Tsunami Warning Center.

The USGS reports that the quake was located:

• 28 km (17 mi) E of Honaunau-Nāpoʻopoʻo, Hawaiʻi
• 46 km (28 mi) ESE of Kailua-Kona, Hawaiʻi
• 60 km (37 mi) WSW of Hilo, Hawaiʻi
• 66 km (40 mi) WSW of Hawaiian Paradise Park, Hawaiʻi
• 312 km (193 mi) SE of Honolulu, Hawaiʻi

According to the US Geological Survey’s Hawaiian Volcano Observatory, the earthquake occurred underneath Moku‘āweoweo, Mauna Loa’s summit caldera, at a depth of 1.2 km (0.74 mi). The USGS “Did you feel it?” Web site reported receiving only one felt report within an hour of the earthquake, consistent with the remote location and shallow depth of the earthquake.

According to the HVO, “deformation monitoring instruments registered the earthquake but show no significant change in deformation rates or patterns that would indicate increased volcanic hazard at this time.”

The agency states that “Magnitude-4 or greater earthquakes occurred in the summit of Mauna Loa 6-7 months prior to the volcano’s two most recent eruptions” in 1975 and 1984, “However, today’s isolated earthquake does not represent a significant departure from the seismic activity rate for the past year.”

For that reason, there was no change to the Volcano Alert Level of “Advisory” for Mauna Loa.

Mauna Loa earthquake shake map (intensity) image credit: NOAA/USGS/PTWC

Mauna Loa earthquake image credit: NOAA/USGS/PTWC