USGS-HVO Lowers Alert Levels on Both Kilauea and Mauna Loa, Dec 13th

USGS - This morning, the USGS Hawaiian Volcano Observatory lowered the alert level and aviation color codes for BOTH Mauna Loa and Kīlauea. At this time, NO lava is erupting onto the surface at either volcano. Mauna Loa and Kīlauea have separate magmatic systems and are not connected at a shallow level. But it remains possible that the volcanoes can influence one another through stresses associated with their eruptions—essentially, when one volcano expands or contracts, it can put pressure on (or take pressure off!) the other volcano. An analogy to describe this is a person standing on a crowded commuter bus during peak hours, feeling a little squeezed and stressed. Once the bus empties out, the person can relax a little and take up more space. In this case, it is possible that Kīlauea has responded to Mauna Loa’s eruption despite the lack of a direct connection. Removal of magma from Mauna Loa’s reservoir by the recent eruption may have allowed Kīlauea to relax. Because Kīlauea’s eruption was occurring at such a low rate, it could have been more susceptible to the small changes in stress that were caused by Mauna Loa’s eruption. However, it is also possible that the change in Kīlauea’s eruptive behavior is a coincidence—with such low levels of activity at Kīlauea prior to Mauna Loa’s eruption, it is difficult to be certain. And of course this may only represent a temporary pause in Kīlauea’s activity. Historical records at Mauna Loa, however, suggest that the eruption there has ended—no previous eruptions have suddenly restarted after reaching the low levels of activity we see today. Scientists will continue to monitor both volcanoes closely and issue updates as needed. To recap: Mauna Loa began erupting at around 11:30 pm on Sunday, November 27. After a few-hour summit phase, the eruption localized on the Northeast Rift Zone at about 6 AM on November 28, and high levels of lava output fed multiple lava flows until activity focused on a single vent -- Fissure 3. Eruptive activity waned significantly on December 8, and by December 10 lava supply to the vent had ceased and SO2 emissions were at near-background levels. Scientists estimate that about 230 million cubic meters (yards) of lava erupted, covering about 43 square kilometers (about 16.5 square miles). Lava in the lava channel fed by fissure 3 flowed 19 km (12.1 mi) and reached to within 3 km (2 miles) of the Daniel K. Inouye Highway (Saddle Road) before stalling. Kīlauea’s eruption began on September 29, 2021, and steadily filled the collapse pit that formed in 2018, adding lava to a previous eruption that occurred during December 2020 – May 2021. The lava depth in the collapse crater is now about 365 meters (1200 feet). Prior to the Mauna Loa eruption, there were signs that lava lake activity was declining based on waning output. By December 9, 2022, no more lava was erupting, and SO2 emissions had returned to near-background levels. [Photo shows Kīlauea’s summit lava pond on December 10 (USGS photo by Joe Bard).]