M-4.1 Earthquake Rattles Kīlauea’s South Flank

Image courtesy of HVO.

A magnitude-4.1 earthquake struck the Big Island Monday.

The US Geological Survey’s Hawaiian Volcano Observatory (HVO) recorded the earthquake beneath Kīlauea Volcano’s south flank at 2:09 pm on Feb. 1.

The quake was centered about eight miles south of Fern Forest, near the Hōlei Pali area of Hawai‘i Volcanoes National Park at a depth of four miles.

Weak to light shaking, with maximum Intensity of IV on the Modified Mercalli Intensity scale, has been reported across the Island of Hawai‘i. At that intensity, damage to buildings or structures is not expected. The USGS “Did you feel it?” service received over 270 felt reports within the first hour of the earthquake.

According to HVO Deputy Scientist-in-Charge David Phillips, the earthquake had no immediate observable impact on the ongoing eruption at Kīlauea’s summit.

“This earthquake was widely felt across the Island of Hawai‘i,” Phillips said. “Please be aware that aftershocks are possible and may be felt. HVO continues to monitor Hawaiian volcanoes for any changes.”

Kīlauea’s south flank has been the site of over 30 earthquakes of magnitude-4.0 or greater during the past 20 years. Most are caused by abrupt motion of the volcano’s south flank, which moves to the southeast over the oceanic crust. The location, depth, and waveforms recorded as part of Monday’s earthquake are consistent with motion along the south flank detachment fault.

For information on recent earthquakes in Hawaii and eruption updates, visit the USGS Hawaiian Volcano Observatory website.