USGS Volcano Hazards Program Volcano Update


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Activity Summary: Eruption continued at two locations. At the summit, tiltmeters recorded deflation and the lava lake level dropped. At Pu`u `O`o, glow was visible from the usual sources within the crater floor. Lava flows southeast of Pu`u `O`o advanced across the coastal plain in two branches with the younger west branch being more active while the east branch was slowing without having reached the ocean. Seismic tremor levels were low, and gas emissions were elevated.

Recent Observations at Kilauea summit: The summit tiltmeter network recorded weak deflation (a little more than 1 microradian over the past day) and the summit lava lake level dropped slowly. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on November 15, 2012; this value is at the low end of measurements made between rise/fall events but still constitutes a background level of emissions. Although not measured this morning, a small amount of ash-sized tephra (including fresh spatter bits and Pele's hair) was probably carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels remained at low values and upper east rift zone seismicity was at background values. Seven earthquakes were strong enough to be located beneath Kilauea: 3 within the upper east rift zone, 1 beneath Pu`u `O`o, and 3 on south flank faults. The GPS network recorded weak extension (about 1 cm) across the summit caldera since November 8.

Background: The summit lava lake is deep within an ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 40 m to more than 200 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. The surface level of the lava lake has again dropped below the inner ledge (~31 m or 100 ft below the floor of Halema`uma`u Crater on October 29, 2012) and has not risen above and flooded the ledge since October 28. The lake level responds to summit tilt changes with the lake receding during deflation and rising during inflation.

Recent Observations at the middle east rift zone vents: Surface flows continued to be active in two branches within the abandoned Royal Gardens subdivision, with the eastern branch slowed in its seaward advance across the coastal plain near the easternmost boundary of Hawai`i Volcanoes National Park; Yesterday, UHH personnel reported the most seaward active flows were 600 m (2,000 ft) from the coast with a stagnant front 290 m (950 ft) from the coast. The western branch was more vigorous and continued to advance rapidly across the coastal plain in plain view of mobile cam 2 (light grey during the day and incandescent at night); the western branch is diverting supply from the eastern branch causing it to slow and stall. There was no ocean entry.

HAZARD ALERT: Lava entering the ocean builds lava deltas. The lava delta and adjacent areas both inland and out to sea are some of the most hazardous areas on the flow field. Frequent delta/bench collapses give little warning, can produce hot rock falls inland and in the adjacent ocean, and can produce damaging local waves. The steam plume produced by lava entering the ocean contains fine lava fragments and an assortment of acid droplets that can be harmful to your health. The rapidly changing conditions near the ocean entry have been responsible for many injuries and a few deaths.

At Pu`u `O`o, no changes: strong glow could be seen from the spatter cone in the north part; the lava lake perched in the northeast part of the crater floor could be seen circulating; weaker glow was intermittently visible from both sources in the south part of the floor. The tiltmeter on the north flank of Pu`u `O`o cone recorded weak deflation mimicking summit tilt. Seismic tremor levels near Pu`u `O`o were low. The most recent (preliminary) sulfur dioxide emission rate measurement was 250 tonnes/day on November 14, 2012, from all east rift zone sources.

Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Pu`u `O`o Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December 2011. Since late December 2011, the flows have remained intermittently active on the pali and the coastal plain but have not entered the ocean. In general, activity waxes with inflation and wanes with deflation.

Hazard Summary: East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary: East rift zone flow field - The active lava flows were within the closed-access Kahauale'a Natural Area Reserve (NAR) and the abandoned Royal Gardens subdivision and can only be viewed from the air. Under favorable weather conditions, these flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093). Pu`u `O`o Cone, the strip of coastal plain nearest the ocean, and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Update in Common Alerting Protocol (CAP) format