USGS Volcano Hazards Program Volcano Update

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Activity Summary: DI inflation continued and the lava lake level hosted minor fluctuations on a slowly rising surface. At Pu`u `O`o, lava circulated in the east pit; glowing spots were seen in the west edge of the north pit; lava flows southeast of Pu`u `O`o pooled on the coastal plain at the base of the pali. Seismic tremor levels were low. Gas emissions were elevated.

Recent Observations at Kilauea summit: The summit tiltmeters recorded continued DI inflation through a third day and the lava lake level fluctuated a small amount while rising slightly; last night, this resulted in several overflows onto the inner ledge with the farthest out of the lake happening at about 3:30 am this morning. 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. Very small amounts of ash-sized tephra (spatter bits and Pele's hair) were carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels were low but increasing slowly with inflation. The GPS receiver network recorded weak extension across the caldera since early August. Eight earthquakes were strong enough to be located beneath Kilauea: 3 deep quakes west of the middle southwest rift zone, 1 west of the summit, 1 within the upper southwest rift zone, 1 within the upper east rift zone, 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 60 m to more than 150 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 lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.

Recent Observations at the middle east rift zone vents: More lava lobes reached the base of the pali yesterday within the abandoned Royal Gardens subdivision and pooled on the coastal plain without advancing significant seaward. The pali flows have been easily visible from the County Viewing Area located to the east in Kalapana and mobile cam 3 while the flows on the coastal plain are in view of mobile cams 2 and 4.

The tiltmeter on the north flank of Pu`u `O`o cone recorded minor fluctuations but the longer-term signal was still obscured by rain effects. 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 continued to circulate and the level remained fairly high in the east pit; glow persisted from spots on the west edge of the crusted north pit; the spot at the base of the southeast flank of Pu`u `O`o, marking a collapse in the roof of the lava tube feeding lava flows downslope, continued to shine brightly overnight in the Pu`u `O`o east cam.

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

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