The Hawaiian Volcano Observatory recorded a magnitude-4.0 earthquake beneath Hawaii Island at 4:25 a.m. Tuesday.
The earthquake occurred underneath Moku‘aweoweo, Mauna Loa’s summit caldera, at a depth of 1.2 km (0.74 mi).
The USGS “Did you feel it?” website received only one felt report within an hour of the earthquake. This report described light shaking (Intensity III). The lack of felt reports is consistent with the remote location and shallow depth of the earthquake.
The earthquake appears to be isolated. As of 6:30 a.m., no aftershocks have been observed.
Magnitude-4 or greater earthquakes occurred in the summit of Mauna Loa six to seven months prior to the volcano’s two most recent eruptions in 1975 and 1984. Tuesday’s isolated earthquake, however, 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 HVO’s Scientist-in-Charge, Christina Neal, the earthquake had no apparent effect on Kilauea Volcano’s ongoing eruptions.