USGS Volcano Hazards Program Volcano Update


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Activity Summary: DI deflation started last night, while the summit lava lake level held steady. At Pu`u `O`o, the lava lake in the northeast pit was active and spots glowed in the west edge of the north pit; lava flows southeast of Pu`u `O`o continued to pool on the coastal plain at the base of the pali and made some seaward progress. Seismic tremor levels were low. Gas emissions were elevated.

Recent Observations at Kilauea summit: After nine days of inflation, the summit tiltmeters recorded the onset of DI deflation at about 8:30 PM last night. Deflation continues this morning. The base level of the lava lake dropped slightly yesterday morning, but has not changed since, even with the ongoing deflation. There were no rise and fall cycles as have occurred sporadically over the past several days. The most recent (preliminary) sulfur dioxide emission rate measurement was 1,200 tonnes/day on September 28, 2012; this value is rather high but not out of the range of values measured at the summit over the past several months; new measurements must await the return of moderate trade winds. Although not measured today, very small amounts of ash-sized tephra (fresh spatter bits and Pele's hair) were probably carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels were steady over the past 24 hours. The GPS receiver network recorded weak extension across the caldera since early August. 20 earthquakes were strong enough to be located beneath Kilauea: 5 within the upper southwest rift zone, 7 within the upper east rift zone, 6 beneath the summit, and 2 on south flank faults.

Background: The summit lava lake is deep within a ~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 50 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. Most recently, the surface level of the lava lake has remained below an inner ledge (~50 m or 165 ft below the floor of Halema`uma`u Crater on October 9, 2012), sometimes rising to flood the ledge. 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 accumulate close to the base of the pali within the abandoned Royal Gardens subdivision, with one branch extending seaward across the coastal plain. This branch has progressed to within about 1.6 km (1 mi) of the shoreline. A field excursion is planned for today to map the flows on the coastal plain. Flows also remain active high on the pali. These flows have been visible from the County Viewing Area located to the east in Kalapana and in mobile cam 3, while the flows on the coastal plain are best viewed by mobile cams 2 and 4.

The tiltmeter on the north flank of Pu`u `O`o cone recorded fluctuations on an inflationary trend until about 3:30 AM this morning, when the signal switched to DI deflation. Seismic tremor levels near Pu`u `O`o were low. The most recent (preliminary) sulfur dioxide emission rate measurement was 220 tonnes/day on September 28, 2012, from all east rift zone sources.

At Pu`u `O`o Crater, the lava lake in the northeastern pit continued to circulate; incandescence was again seen from points on the west edge of the crusted north pit. The skylight high on the tube system which had been glowing for the past few months is now dark, suggesting that it has been plugged.

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. Since late December, 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 new breakout 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, glow from these flows may be reflected in clouds which 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