USGS Volcano Hazards Program Volcano Update

HVO update page and observatory web site

Activity Summary: No significant change in hazards: At the summit, the lava lake rose slowly. At Pu`u `O`o vent in the middle east rift zone, the east lava pond overflowed yesterday afternoon and produced at least one lobe that started down the northeast flank of the cone. The Peace Day pali breakout flow progressed across the coastal plain while the main flow branch continued to enter the ocean in at least 2 locations spanning the Hawai`i Volcanoes National Park boundary. Gas emissions remained elevated.

Recent Observations at Kilauea summit: The summit tiltmeter network recorded weak inflation totaling more than 1.5 microradians since early Sunday (5/5). The summit lava lake started to rise at about 8:30 am yesterday morning. The most recent (preliminary) sulfur dioxide emission rate measurement was 500 tonnes/day on May 2, 2013; these measurements are a minimum and were made during a time of spattering (and elevated gas release); new measurements must await the return of moderate trade winds. The gas plume still carries a very small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair) out of the vent and deposits it on nearby surfaces. Seismic tremor levels remained at low values.

Ten earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 2 south of the summit caldera, 1 within the upper east rift zone, 1 within the middle east rift zone, 2 north of the east rift zone, and 4 on south flank faults. Since early March, the GPS receivers located on either side of the summit caldera recorded slow contraction.

Background: The summit lava lake is 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 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 receding during deflation and rising during inflation.

Recent Observations at the middle east rift zone vents: At Pu`u `O`o, the east lava pond started to overflow around 2:30 pm yesterday and continued through this morning to the south and out of site of the Pu`u `O`o Webcams; at 4:40 am this morning, the overflows extended into the field of view of the Pu`u `O`o East flank thermal camera (ETcam)and onto the northeast flank of Pu`u `O`o cone. The spatter cones glowed within Pu`u `O`o Crater overnight. The tiltmeter on the north flank of Pu`u `O`o cone recorded weak inflation starting at 10:30 am yesterday, an abrupt deflation just after 3 pm almost certainly related to the above-mentioned east pond overflow, and continued weak inflation through this morning. GPS receivers on the north and south flanks of Pu`u `O`o cone have been recording weak extension since mid-April along with increasing seismic tremor levels. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on April 26, 2013, from all east rift zone sources; these values have ranged between 150 and 450 t/d in 2013.

The Peace Day pali breakout that started Friday afternoon continued making progress across the coastal plain while the main branch of the Peace Day flow continued to enter the ocean at 2 persistent locations (inside and outside Hawai`i Volcanoes National Park).

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.

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. 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 in 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