Mauna Loa stable despite small-magnitude earthquakes

Shallow seismicity (less than 2.5 mi or 4 km depth) beneath Mauna Loa’s summit and upper-elevation flanks has been stable over the past month with approximately 15 small-magnitude earthquakes (below M3.0) detected.

A total of approximately 40 earthquakes were detected on the volcano across all depths, comparable to the number detected in the previous month.

Starting in July 2023, there had been an elevated rate of earthquakes deeper than 8 mi (13 km) beneath and southwest of Mauna Loa’s summit caldera, then this area saw a deep earthquake swarm in late October and early November. Since then, however, the rate of deep earthquakes has returned to background levels.

Data from Global Positioning System instruments on Mauna Loa indicate inflation as magma replenishes the summit reservoir system. 

Gas and temperature data from a station on Mauna Loa’s Southwest Rift Zone show no significant changes in the past month.

HVO continues to closely monitor Mauna Loa and will issue another update in one month, or earlier should conditions change significantly.