No tsunami threat after two “moderate” Mauna Loa earthquakes, 4.6 and 5.0 M

(Update: 11:46 a.m., Oct. 14, 2022)

Scientists say two “moderate” earthquakes occurred within 24 seconds of each other at 9:07 a.m. on Mauna Loa’s flank, followed by a string of smaller aftershocks this morning.

The first 4.6 magnitude quake was located slightly offshore and south of Pāhala, and was about 8 miles deep. It was followed by a larger 5.0 earthquake just south of Pāhala that was 4.6 miles beneath Highway 11, according to scientists with the USGS Hawaiian Volcano Observatory.

Most of the aftershocks were 3.0 or smaller, but there were some larger ones up to magnitude-4.0 at 9:16 a.m. HVO experts say the aftershock sequence continues at a depth of 0–7 miles, and south of Pāhala, and anticipates aftershocks to continue for “several days to possibly weeks.”

“The two earthquakes occurred within 24 seconds of each other creating shaking of longer duration and possibly greater intensity than either of the earthquakes would have created on their own,” according to an HVO information statement.

The HVO reports that this sequence of earthquakes “appears to be related to readjustments along the southeast flank of Mauna Loa volcano.”

Scientists say there has been “no immediate effect on the continuing unrest beneath Mauna Loa summit,” which remains elevated. 

“On several occassions large earthquakes have preceded past eruptions of Mauna Loa, though these have typically been larger than today’s earthquakes.  It is not known at this time if this sequence of earthquakes is directly related to the ongoing unrest on Mauna Loa,” according to the HVO statement.

(Posted: 9:10 a.m., Oct. 14, 2022)

There is no tsunami expected after a preliminary magnitude 5.1 earthquake reported at 9:07 a.m. on Friday, Oct. 14, 2022 in the Mauna Loa area of Hawaiʻi Island. The Pacific Tsunami Warning Center and the Hawaiʻi Emergency Management Agency both report that there is no tsunami threat following the quake.

The Hawaiʻi Emergency Management Agency reports that a swarm of small earthquakes near Pāhala appears to have started with two larger shakes about 24 seconds apart in different sections of Mauna Loa’s flank.

The first quake was 4.6 in magnitude and occurred on the southeastern flank of Mauna Loa at 9:07 and five seconds; and the second, stronger 5.1 quake occurred at 9:07 and 29 seconds.

The USGS released the approximate distances of nearby places in relation to the events.

Nearby locations in relation to 5.1 quake:

• Pāhala, Hawaiʻi, 4 miles NNE
• Hawaiian Paradise Park, Hawaiʻi, 46.3 miles NE
• Kailua-Kona, Hawaiʻi, 46.8 miles NW
• Hilo, Hawaiʻi, 48.3 miles NE
• Honolulu, Hawaiʻi, 213.4 miles NW

Nearby locations in relation to 4.6 quake:

• Pāhala, Hawaiʻi, 4.9 miles N
• Hawaiian Paradise Park, Hawaiʻi, 46.4 miles NE
• Kailua-Kona, Hawaiʻi, 48.3 miles NW
• Hilo, Hawaiʻi, 48.8 miles NNE
• Honolulu, Hawaiʻi, 214.9 miles NW

The larger quake occurred at a depth of 7.4 km, and the smaller quake occurred at a depth of 13.4 km, according to the USGS.

An emergency notice indicates that some areas may have experienced strong shaking.

There were about 20 felt responses within the first 15 minutes of the earthquake recorded by the USGS Did You Feel It? website. The majority of felt reports came from the Kailua-Kona, Hilo, Volcano, and Nāʻālehu areas of Hawaiʻi Island.

The USGS Hawaiian Volcano Observatory reports that this past week, about 320 small-magnitude earthquakes were recorded below the summit and upper elevation flanks of Mauna Loa. The majority of these occurred at shallow depths less than 9 miles below sea level, according to the HVO’s latest Volcano Watch report.

Mauna Loa is not erupting and remains at Volcano Alert Level ADVISORY, according to the HVO’s latest update. “This alert level does not mean that an eruption is imminent or that progression to an eruption from the current level of unrest is certain,” the HVO reports.

*This is a developing story and more information will be posted as it becomes available.