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 stable conditions and the lava lake continued to circulate while its level remained stable. At the middle east rift zone, the Kahauale`a 2 lava flow was slowly expanding as multiple breakouts burning small patches of forest north of Pu`u `O`o. Southeast of Pu`u `O`o, scattered active breakouts were seen on the pali and coastal plain with breakouts just inland of the former ocean entry; lava was not entering the ocean. Gas emissions remained elevated.

Recent Observations at Kilauea summit: Summit tiltmeters recorded minor fluctuations, and one minor offset at 7:15 am yesterday, and the lava lake level remained fairly stable at about 48 m (157 ft) below the Halema`uma`u Crater floor. Elevated gas emissions continued: the most recent sulfur dioxide emission rate measurement was 1,100 t/d on September 3, 2013 - the higher value represents a period in which spattering activity and gas release from the lava lake were active; however, this value is a minimum because the data were acquired close to the vent where the plume is most dense and challenging to fully characterize. A small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair) was carried out of the vent with the gas and deposited onto nearby surfaces.

Seismic tremor levels remained low. Sixteen earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 1 within the lower southwest rift zone, 1 just west of the summit caldera, 1 within the upper east rift zone, and 13 on south flank faults. GPS receivers on opposite sides of the summit caldera recorded changes that mimicked the summit tilt in the short term (extension while summit tiltmeters record inflationary tilt and contraction during deflationary tilt) over a longer-term trend of weak contraction similar to the brief contraction at the end of July.

Background: The summit lava lake is within a 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 September 3, 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 recorded minor fluctuations in the short term but no longer-term trend. The Pu`u `O`o vent fed two lava flow fields - the Kahauale`a 2 flow to the north and the Peace Day flow to the southeast.

Spatter cones on the north and south portion of the crater floor of Pu`u `O`o showed continued incandescence while the northeast spatter cone continued to feed the Kahauale`a 2 lava flow extending 3.2 km (2 mi) to the north. Similar to past weeks, PNcam views showed scattered active breakouts on the Kahauale`a 2 flow and burning along the forest line north of Pu`u `O`o. Lava seems to be filling in this area rather than advancing in any one direction.

On the coastal plain more than 7 km (4.3 mi) southeast of Pu`u `O`o, active breakouts from the Peace Day flow occurred in a few locations between at the base of the pali and the coastline. Minor breakouts inland of the former Kupapa`u delta were fed by the older main lava tube while breakouts to the west in the mid-coastal plain were fed by a western branch of the Peace Day lava tube system; lava was not entering the ocean.

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 (see HAZARD ALERT above). 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. A small part of the western flow field near the coast may be within Hawai`i Volcanoes National Park (see below for access info). Under favorable weather conditions, active flows-when present-can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093). 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

Update in Common Alerting Protocol (CAP) format