USGS Volcano Hazards Program Volcano Update


HVO update page and observatory web site


Activity Summary: Eruptions continued at two locations: At the summit, there was weak inflation and a small rise in lava lake level. Pu`u `O`o also inflated, and glow was visible from the usual sources on the crater floor. Lava flows were active on the coastal plain, and lava is entering the ocean near Kupapa`u. Seismic tremor levels were low, and gas emissions were elevated.

Recent Observations at Kilauea summit: The summit tiltmeter network recorded very weak inflation, with a slight increase in variability and only a little net inflation since December 2. The lava lake level was variable as well, rising a meter or two and partly inundating the lowest parts of the ledge on the south side of the lake several times over the past day. Overall, there was a small net increase in lake level. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on November 28, 2012. A small amount of ash-sized tephra (including fresh spatter bits and Pele's hair) was likely carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels have dropped back to November's low values. Eight earthquakes were strong enough to be located beneath Kilauea: 4 in the upper east rift, 2 on the middle east rift, 1 west of the summit, and 1 offshore beneath south flank faults. The GPS network recorded neither net extension nor contraction across the summit caldera since November 2.

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 has varied from about 25 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 remained 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, 2012. 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: Lava flows remained active in two branches on the coastal plain: a tiny western branch, and a larger eastern branch with scattered surface activity extending from the pali to the coast east of the easternmost boundary of Hawai`i Volcanoes National Park. An ocean entry marked by a weak and variable plume continues near Kupapa`u. Part of the eastern flow branch constitutes a second front, which is traveling along the east side of the flows currently entering the ocean and roughly mid-way across the coastal plain.

HAZARD ALERT: Lava entering the ocean builds lava deltas. The lava delta and adjacent areas are some of the most hazardous areas on the flow field. Frequent delta/bench collapses give little warning, can produce explosions capable of throwing both dense and molten rocks hundreds of meters (yards) in all directions (inland as well as out to sea), 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, glow could be seen emanating from several locations on the crater floor: the spatter cone on the northwest side of the crater beneath the webcams, the northeastern lava lake, and both spatter cones in the southeastern part of the floor. The tiltmeter on the north flank of Pu`u `O`o cone recorded slow inflation. GPS receivers on opposite sides of the crater recorded a minor amount of extension since November 23, mimicking tilt. Seismic tremor levels near Pu`u `O`o remain low. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on November 28, 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 and finally re-entered the ocean starting on November 24, 2012. 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