Two magnitude 4 quakes shake Kilauea area

The Maui News

There were two magnitude 4-sized earthquakes within 15 hours of each other and a mile apart beneath Kilauea’s southern flank Thursday and Friday, the U.S. Geological Survey’s Hawaii Volcano Observatory reported.  A 4.6 quake struck at about 11:20 p.m. Thursday night about 4.3 miles below the earth’s surface in the Fern Forest area of Kilauea. It triggered an alert from the Maui County Emergency Management Agency that no tsunami was created by the quake.

Then at 2:19 p.m. Friday, a 4.3 quake in the same general area shook the island. It was centered about 3.5 miles south of ‘Pu’u O’o, about a mile north of Thursday night’s quake. This quake occurred about 4.4 miles beneath the earth’s surface.

Hawaii Volcano Observatory seismologist Ashton Flinders said the earthquake had no apparent effect on Kilauea or Maunaloa volcanoes.

“We do not see any immediate changes in activity at Kilauea or Maunaloa as a result of either this earthquake or the M4.6 earthquake last night,” Flinders said in a Friday news release. “It is not uncommon for aftershocks like these to happen in relatively short succession. Further aftershocks remain possible and may be felt.”

The observatory continues to monitor Kilauea and other Hawaii volcanoes for any changes.

Aftershocks are the result of crustal settling from larger earthquakes, such as the magnitude 6.9 quake that occurred on May 4, 2018. The location, depth and wave forms recorded from Friday’s earthquake are consistent with slippage along this southern flank fault, the observatory said.

While most earthquakes under Kilauea’s southern flank are caused by abrupt motion of the volcano to the southeast over the oceanic crust, some patches of the fault that did not slip during the larger earthquakes are primed to slip as subsequent aftershocks, the observatory said.

For more information, go to volcanoes.usgs.gov/hvo/earth quakes/.