Seismic activity reported at Kīlauea’s upper East Rift Zone

The Hawaiian Volcano Observatory is reporting an “abrupt increase” in seismic activity recently in the upper East Rift Zone of Kīlauea.

The earthquakes were accompanied by a “local deformation” at 11 a.m. July 22, marking the initial stage of magma intruding underground in the area. The activity is concentrated between Pauahi Crater and Maunaulu along Chain of Craters Road in Hawaiʻi Volcanoes National Park.    

At 3:30 a.m. July 23, a stronger pulse of seismic activity and local deformation began at the same time as deflation of Kīlauea summit. The summit has been steadily deflating since then as magma moves into the vertical, sheet-like body (dike) beneath the rift zone near Pauahi Crater, according to observatory officials.

Then, at 10 a.m. today, a third pulse of activity started as dike emplacement continued. Each pulse lasted approximately two to three hours, but seismic activity and deformation continued at levels well above normal between the pulses, officials said. 

In total, there have been nearly 1,000 earthquakes located in the upper East Rift Zone of Kīlauea over the past three days, officials reported. A quarter of those earthquakes exceeded magnitude-2 and the largest event was a magnitude-3.6.

Earthquakes have remained 0.6 to 1.8 miles beneath the surface. “As of 4:30 p.m. today, the dike continues to grow, and unrest may continue to wax and wane with changes to the input of magma into the area. An eruption is not currently imminent, but conditions could change rapidly,” officials said. 

Unrest has been restricted to upper rift zone. No unusual activity has been noted along Kīlauea’s middle and lower East Rift Zones or the Southwest Rift Zone. The Hawaiian Volcano Observatory continues to closely monitor Kīlauea for changes.

The observatory is operated by the US Geological Survey.