No Tsunami Expected After 4.1 Mauna Loa Earthquake on Hawai‘i Island

PC: Hawaiian Volcanoes Observatory.

There is no tsunami expected after a 4.1 preliminary magnitude earthquake reported at 7:44 a.m. on Friday, Dec. 4, 2020 on the Western Flank of Mauna Loa on Hawaiʻi Island.

The Pacific Tsunami Warning Center issued a local tsunami information statement saying no tsunami is expected, however some areas may have experienced shaking.

The quake was documented by the USGS Hawaiian Volcano Observatory. The HVO reports that the quake was centered about 22 km (14 miles) east-northeast of Hōnaunau-Nāpōʻopoʻo, at approximately 5 km (3 miles) below sea level.

In the first hour following the earthquake, there were more than 130 “felt” responses on the USGS “Did You Feel It?” website, with most reports coming out of Kailua-Kona and Naʻalehu.

According to HVO acting Scientist-in-Charge David Phillips, the earthquake had no apparent effect on Kīlauea or Mauna Loa volcanoes. “We do not currently observe any changes in activity at Kīlauea or Mauna Loa as a result of this earthquake. Please be aware that aftershocks are possible and may be felt. HVO continues to monitor Kīlauea and other Hawaiian volcanoes for any changes.”

The HVO reports that today’s earthquake “does not represent a significant departure from the seismic activity rate for the past year,” so the Volcano Alert Level for Mauna Loa will remain at Advisory.

According to the HVO, other Mauna Loa monitoring data streams show no significant change in deformation rates or patterns that would indicate increased volcanic hazard at this time.

The earthquake this morning occurred in a location that has exhibited seismicity over the past several years. Earthquakes in this location, approximately 5 km (3 miles) northwest of Mauna Loa summit, are generally less than 8 km (5 miles) below the surface and smaller than magnitude-2, the HVO reports.