Volcano Activity Update: Dec. 28, 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, ranging about 102 to 116 feet below the vent rim. On the East Rift Zone, the 61g lava flow remained active downslope of Pu‘u ‘Ō‘ō, with scattered breakouts on the pali and coastal plain, but no ocean entry. The 61g flows do not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. Rates of deformation and seismicity remain above long-term background levels, but rates are decreased from earlier in the year. Similar decreases have occurred in the past during the ongoing period of unrest; it is uncertain if these lower rates will persist or will pick up again in the near future. Small-magnitude earthquakes occurred beneath the summit caldera and upper Southwest Rift Zone at depths less than three miles. A few deeper earthquakes were scattered beneath the volcano’s southeast and west flanks at depths of three to 12 miles. GPS and 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.

One earthquake with three or more felt reports occurred in the Hawaiian Islands this past week: a magnitude-3.1 earthquake four miles west of Kalaoa at a depth of six miles on Dec. 26 at 2:50 a.m. HST.

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.