Swarm of small quakes gently rattles Mauna Loa

Mauna Loa Volcano is not erupting, despite a swarm of small earthquakes detected Thursday, the US Geological Survey said.

A small swarm of shallow seismicity, that began at 1 a.m. Thursday, is occurring beneath the upper Ka‘oiki seismic zone, under Mauna Loa’s southeast flank and northwest of Kilauea’s summit. Other Mauna Loa monitoring data streams remain stable and show no signs of increased activity.

The U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) has recorded more than 40 earthquakes beneath the upper Ka‘oiki seismic zone, about 13 miles west-northwest of Volcano. These earthquakes are occurring in a cluster about a mile wide, half a mile to 4 miles below the surface.

The largest event in the sequence, so far, was a magnitude-3.5 earthquake, with the bulk of the events being less than magnitude-2 and not widely reported by residents. Reported felt events were described as weak shaking.

Clustering of shallow earthquakes in this region does not mean an eruption is imminent. HVO has recorded shallow earthquakes in this area for many decades across several eruptive cycles at both Kilauea and Mauna Loa. These earthquakes do not show any signs of magmatic involvement and are part of normal re-adjustments of the volcano due to changing stresses within it. Other monitoring data streams for Kilauea and Mauna Loa, including ground deformation, gas, and imagery, show no signs of increased activity.


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