More than 38 earthquakes in seismic swarm beneath summit of Mauna Loa

An estimated 38 small earthquakes have occurred beneath the summit of Mauna Loa volcano since 2 a.m. on Friday, Sept. 23, 2022. The US Geological Survey’s Hawaiian Volcano Observatory reports that the quakes are part of a small seismic swarm beneath the summit caldera region.

Most earthquakes through 10:30 a.m., have occurred in a cluster about 3.1 miles wide and -1.2 to 0.6 miles below the surface.  The magnitude has range has been up to 2.7.

The HVO reports that these earthquakes may result from changes in the magma storage system and/or may be part of normal re-adjustments of the volcano due to changing stresses within it.

“Seismic activity beneath Mauna Loa has been gradually increasing over the past two months,” according to HVO Scientist-in-Charge Ken Hon.  “Small earthquake swarms are considered a normal part of this increase in activity.  Currently there are no indications that magma is moving toward the surface and other monitoring systems are displaying normal behavior.  Levels of seismicity and deformation remain below those recorded during the winter of 2021.  HVO will continue to closely monitor this activity and report any significant changes.”

The USGS HVO reports that the five most recent magnitude 4 or greater earthquakes in Hawaiʻi have occurred at the following times and locations:

• 2022 Sept. 5—Magnitude 4.0—7 miles ENE of Pāhala, Island of Hawaiʻi
• 2022 Aug. 22—Magnitude 4.0— 6 miles E of Pāhala, Island of Hawaiʻi
• 2022 July 27—Magnitude 4.6—27 miles ESE of Nāʻālehu, Island of Hawaiʻi
• 2022 May 22—Magnitude 4.7—2 miles NW of Hōlualoa, Island of Hawaiʻi 
• 2022 April 15—Magnitude 4.6—6 miles E of Pāhala, Island of Hawaiʻi