USGS MAUNA LOA AFTERNOON UPDATE FOR DAY 9

The Northeast Rift Zone eruption of Mauna Loa continues. One active fissure, fissure 3, is feeding a lava flow downslope. Fissure 3 is generating a lava flow traveling to the north toward the Daniel K. Inouye Highway (Saddle Road) that has reached relatively flatter ground and slowed down significantly over the past several days, as expected. The Hawaiian Volcano Observatory has not made observations of the eruption since this morning due to weather obscuring views and preventing fieldwork. As of 5:00 a.m. today, December 6, the flow front was about 1.93 mi (3.1 km) from the Daniel K. Inouye Highway (Saddle Road). The lava flow advanced at an average rate of about 68 feet per hour (21 meters per hour) over the 24 hour period prior to this morning; this rate is about twice the rate for the past several days. Over shorter periods yesterday, the advance rate varied from 62 to 90 feet per hour (18.8 to 27.4 m per hour). The lava flow remains active and is continuously supplied from the fissure 3 vent. Lava flow advance rates may be highly variable over the coming days and week. Lava flows advance more slowly, spread out, and inflate on the flat ground between Mauna Loa and Mauna Kea. Individual lobes may advance quickly, and then stall. Additional breakouts may occur if lava channels get blocked upslope. There are many variables at play, and the direction and timing of flow advances are expected to change over hours to days, making it difficult to estimate when or if the flow will impact Daniel K. Inouye Highway. Sulfur dioxide (SO2) emission rates of approximately 120,000 tonnes per day (t/d) were measured on December 4, 2022, and remain elevated at this time. Volcanic gas is rising high and vertically into the atmosphere before being blown to the west at high altitude, generating vog (volcanic air pollution) in areas downwind. The International Volcanic Health Hazard Network has detailed information about vog: https://vog.ivhhn.org/. Forecasts for the dispersion of vog can be found on the Mauna Loa Vog Forecasting Dashboard: https://vog.ivhhn.org/content/mauna-loa-eruption. Pele's hair (strands of volcanic glass) fragments are being wafted great distances and have been reported as far Honoka‘a. Tremor (a signal associated with subsurface fluid movement) continues beneath the currently active fissure. This indicates that magma is still being supplied to the fissure, and activity is likely to continue as long as we see this signal. There is no active lava within Moku'āweoweo caldera nor the Southwest Rift Zone. We do not expect any eruptive activity outside the Northeast Rift Zone. ---- END OF USGS UPDATE ---- Map from USGS: Helicopter overflights on November 30, December 1, December 2, and December 5, 2022, allowed for aerial visual and thermal imagery to be collected of the Northeast Rift Zone eruption of Mauna Loa. These maps show evolution of the lava flow from fissure 3 over those days. The scale of the thermal map ranges from blue to red, with blue colors indicative of cooler temperatures and red colors indicative of warmer temperatures.