Kīlauea volcano on Big Island quiets down amid elevated unrest

Signs of elevated unrest continue at the summit of Kīlauea on the Big Island. However, during the past couple of days, the volcano has quieted down somewhat.

According to the Hawaiian Volcano Observatory’s 9:30 a.m. Aug. 18 update for Kīlauea, the number of earthquakes at the summit has decreased compared to the past three weeks of increased seismic activity. Increases in ongoing summit inflation also have stopped.

Just a few days ago, on the morning of Aug. 15, the volcano seemed to be rumbling louder, with a swarm of about 50 shallow earthquakes at depths of 1 to 2 miles in an area south of Halemaʻumaʻu crater. The swarm was likely caused by magma movement in the volcano’s south caldera region, which is consistently observed at the summit.

During the past two weeks, nearly 500 quakes of magnitude-3.2 and smaller have been recorded in the summit region, with a single magnitude-4.3 temblor on Aug. 13.

The observatory said it is unclear whether the recent decreases in activity are a short pause in the elevated unrest or a return to background levels.

There has been no active lava seen in Halemaʻumaʻu crater since June 19.

No unusual activity has been noted along Kilauea’s East Rift Zone or Southwest Rift Zone either, but steady rates of ground deformation and seismicity continue along both.

Sulfur dioxide (SO2) emissions from the summit remain low; the most recent rate of about 86 tonnes per day was measured Aug. 15. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone of the volcano remain below SO2 detection limits, indicating SO2 emissions from Puʻuʻōʻō are negligible.

Kīlauea’s alert level remains at Advisory. The Hawaiian Volcano Observatory continues to closely monitor the volcano.