Big Island volcano rattled by more than 300 earthquakes during past 24 hours

More than 300 earthquakes have rumbled during the past 24 hours beneath the summit of Kīlauea volcano on the Big Island, mostly below the south caldera region and at depths of 1 to 1.8 miles.

The volcano is not erupting, but summit earthquake counts have increased as part of a sesimic swarm that began the afternoon of June 27 with magnitude-2.9 and magnitude 3.4 quakes.

The 300 quakes during the past day is more than triple the seismic rate from several days ago.

Inflation in the summit and upper rift zones continue to be moderately elevated, which as has been persistent since the end of the short-lived June 3 eruption.

Inflation continues around the summit, but rates have slowed.

Tiltmeters at Uēkahuna northwest of the summit and Sand Hill southwest of the summit each recorded approximately 1 microradian of net inflation during the past 24 hours.

The most recent measurement of the summit’s sulfur dioxide emission rate was about 75 tonnes per day June 28.

Any substantial increases in seismicity and/or deformation could result in a new eruption within or near the summit region, but there are no signs of an imminent eruption at this time.

Since the June 3 eruption, magma has been repressurizing the storage system beneath Halemaʻumaʻu and the south caldera region of the volcano, activating earthquakes in the upper East Rift Zone and in the caldera south of Halemaʻumaʻu.

It’s not possible to say whether this increase in activity at Kīlauea will lead to an intrusion or eruption in the near future, or simply continue as seismic unrest.

Changes in the character and location of unrest can occur quickly.

Earthquake activity and ground deformation in the middle and lower East Rift Zone and lower Southwest Rift Zone remain low.

Recent eruptions and ongoing unrest have been restricted to the summit and upper rift zone. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone — the site of 1983-2018 eruption — remain below detection limits for sulfur dioxide, indicating emissions are negligible.

The Hawaiian Volcano Observatory continues watch Kīlauea closely and provide daily updates about the volcano’s status.

Should activity change significantly, a Volcanic Activity Notice will be issued.