USGS Volcano Hazards Program Volcano Update

HVO update page and observatory web site

Activity Summary: Eruption at two locations continued with no significant changes. Summit instruments recorded temporary stability while the lava lake level remained stable. At the middle east rift zone, the Kahauale`a 2 lava flow was active as scattered breakouts, some burning forest north of Pu`u `O`o. The Peace Day flow southeast of Pu`u `O`o hosts a single minor breakout above the pali. Gas emissions remained elevated.

Recent Observations at Kilauea summit: Summit tiltmeters recorded minor fluctuations and the lava lake level remained stable at a measured 41 m (135 ft) below the floor of Halema`uma`u Crater. Gas emissions continued to be elevated: the most recent sulfur dioxide emission rate measurement was 700 t/d on October 15, 2013 - the higher value represents a period in which spattering activity and gas release from the lava lake were active; however, these values are minimums because the data were acquired close to the vent where the plume is most dense and challenging to fully characterize. A moderate amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the spattering sinks) was probably carried out of the vent with the gas and deposited onto nearby surfaces.

Seismic tremor levels fluctuated with one dropout between 6:30 and 8 pm last night. Fourteen earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 2 within the Ka`oiki Pali area, 2 beneath Halema`uma`u Crater, 3 south of Halema`uma`u Crater, 3 within the upper east rift zone, 1 within the middle east rift zone (north of Pu`u `o`o), and 3 on south flank faults. GPS receivers spanning the summit caldera recorded line length changes that mimicked the short-term changes in tilt (DI tilt events) in addition to ~2 cm of extension over the past month; the long-term, cross-caldera measurements indicate continued extension at a rate averaging 10 cm/yr (4 in/yr) since March, 2010.

Background: The summit lava lake is within a nearly-cylindrical vent cavity with a diameter of ~160 m (520 ft) and 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 mostly below the inner ledge (~31 m or 100 ft below the floor of Halema`uma`u Crater on October 29, 2012) and has risen above and flooded the ledge in October 2012 and January 2013 before receding to greater depths. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation.

Recent Observations at the middle east rift zone vents: The tiltmeter at Pu`u `O`o cone recorded minor fluctuations. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on October 8, 2013, from all east rift zone sources; these values have ranged between 150 and 450 t/d in 2013 and are made at a greater distance from the sources where the plume is more easily characterized. GPS receivers on the north rim and south flank of Pu`u `O`o cone recorded minor fluctuations over weak extension (less than 1 cm over the past month). The Pu`u `O`o vent primarily feeds the Kahauale`a 2 flow to the north; the older Peace Day flow to the southeast may have a single, weakly active breakout.

Spatter cones on the north and south portion of the Pu`u `O`o crater floor displayed persistent glow while the northeast spatter cone continued to feed the Kahauale`a 2 lava flow extending 5.8 km (3.6 mi) to the north (mapped on 10/21). On Monday, October 21, HVO geologists found the breakouts active in only the northern half of the flow with a narrow finger extending northeast into the forest. The Kahauale`a 2 flow was also burning forest at other contact points along its northern edge.

The Peace Day flow was confirmed weakly active above the pali. On Monday, October 21, HVO geologists mapped a small breakout consisting of two lobes from the Peace Day tube about 3 km (1.9 mi) southeast of Pu`u `O`o that had minor pahoehoe activity.

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 (Peace Day 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. The Kahauale`a flow, which started from the spatter cone/lava lake at the northeast edge of the Pu`u `O`o crater floor in mid-January, 2013, was dead by late April, but a new flow (Kahauale`a 2) became active in the same general area in early May. 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; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Lava deltas, which can collapse into the ocean without warning, are extremely hazardous and should be avoided. 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 - Most of the flow field is 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, active flows-when present-can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road within Hawai`i Volcanoes National Park. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; Park access and viewing information can be found at Hawai`i Volcanoes National Park is closed as of October 1, 2013, due to a lapse in appropriations.

Update in Common Alerting Protocol (CAP) format