USGS Volcano Hazards Program Volcano Update


HVO update page and observatory web site


Activity Summary: Eruption continued at two locations: At the summit, the lava lake level resumed rise/fall events. At Pu`u `O`o, glow was generally visible from the usual sources within the crater floor. Lava flows southeast of Pu`u `O`o were active within two branches on the coastal plain and there was no evidence of an ocean entry visible in the webcams. Seismic tremor levels were low, and gas emissions were elevated.

Recent Observations at Kilauea summit: The summit tiltmeter network recorded a brief period of minor deflation between 5 and 6 pm yesterday but no other significant changes. Rise/fall events resumed with the first between 2:30 and 5 am this morning and the lava lake may have risen slightly over the past day. The most recent (preliminary) sulfur dioxide emission rate measurement was 600 tonnes/day on November 20, 2012; this value is at the low end of measurements made between rise/fall events but still constitutes a background level of emissions. A small amount of ash-sized tephra (including fresh spatter bits and Pele's hair) was carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels remained at low values. Eleven earthquakes were strong enough to be located beneath Kilauea: 1 at the west edge and 1 at the south edge of the summit caldera, 1 within the upper east rift zone, 1 within the middle east rift zone, and 7 on south flank faults. The GPS network recorded weak contraction across the summit caldera over the past few days mimicking summit tilt.

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 were most active in the easternmost of two branches within the abandoned Royal Gardens subdivision and private property to the east of Hawai`i Volcanoes National Park. Yesterday, HVO geologists mapped the front of the eastern branch across the coastal plain, along the easternmost boundary of Hawai`i Volcanoes National Park, to be about 175 m (575 ft) from the coast (see map). The shorter western branch appeared far less active on the ground yesterday and in Webcams overnight. There was no ocean entry plume visible in any of the webcams through this morning; however, the flows were advancing into an area with a slightly steeper seaward slope and, if they continue at their current rate, could reach the ocean in the next few days.

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, strong glow could be seen from the spatter cone in the north part and the circulating lava lake perched in the northeast part of the crater floor; 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 very weak inflation until just after midnight; GPS receivers on opposite sides of the crater recorded neither extension nor contraction over the past few days. Seismic tremor levels near Pu`u `O`o were low. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on November 20, 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