Hawai‘i Volcano Activity Update: Dec. 21, 2017

Visitors observe Kīlauea summit lava lake last month from the Jaggar Museum observation deck, open 24 hours a day in Hawai‘i Volcanoes National Park. NPS photo/Janice Wei.

This past week, Kīlauea Volcano’s summit lava lake level fluctuated with summit inflation and deflation and ranged about 398 to 144 feet below the vent rim. On the East Rift Zone, the 61g flow remained active, with scattered breakouts downslope of Pu‘u ‘Ō‘ō, but not at the ocean entry. The 61g flows do not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. During the past week, small-magnitude earthquakes continued to occur beneath the volcano. Shallow seismicity was concentrated beneath the summit caldera and upper Southwest Rift Zone at depths less than three miles. Additional deeper seismicity three to 12 miles was scattered beneath the southeast flank of the volcano. Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements continue to show deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone. No significant changes in volcanic gas emissions were measured. Overall rates of deformation and seismicity have decreased towards long-term background levels. Similar decreases have occurred in the past during the ongoing period of unrest that started in 2014; it is unknown if these low rates will persist or if they will pick up again in the near future.

No earthquakes were reported to be felt in the Hawaiian islands during the past week.

The “Hawai‘i Volcano Activity Update” is a weekly article written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.

Call for summary updates at (808) 967-8862 (Kīlauea) or (808) 967-8866 (Mauna Loa); email questions to askHVO@usgs.gov.