USGS Volcano Hazards Program Volcano Update

HVO update page and observatory web site

Activity Summary: Conditions of unrest have stabilized: At the summit, there was weakening inflation with a lava lake whose level fluctuated with the presence or absence of spattering. At Pu`u `O`o vent in the middle east rift zone, inflation slowed, a new flow issued within the crater, and lava flows remained active on the flank of the cone to the northeast and north. The Peace Day pali flow remained active on 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 only 0.2 microradians of inflationary tilt over the past 24 hours and the summit lava lake remained at the same level with abundant, travelling spattering sources and minor temporary jumps when spattering was absent. This morning, weak trade winds seem to have returned and the plume is drifting to the southwest - new measurements must await the return of moderate trade winds. Gas emissions remain elevated with the plume carrying a very small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair) out of the vent and depositing it on nearby surfaces. Seismic tremor levels remained at low values with sporadic drops in value about every 3 hours when spattering on the lava lake ceased; conversely when there are two or more spattering areas on the lava lake, the tremor levels are nearly double the values when only one spatterer is present.

Thirteen earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 2 along the Ka`oiki Pali,5 within the upper east rift zone, 1 deep quake within the middle east rift zone, and 5 on south flank faults. Until early afternoon yesterday, minor earthquakes too weak to locate occurred more frequently, up to 9/hr, in the upper east rift zone. The GPS receivers located on either side of the summit caldera recorded slow extension in May following minor contraction through April.

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, lava flows continued to issue from the east lava pond area with most of the lava flowing to the northeast and north (visible in ETcam and PNcam) and a minor branch to the east (visible in ETcam and PEcam) on the flank of Pu`u `O`o cone. In addition, the southwest spatter cone (visible in PTcam and POcam) sporadically erupted lava starting just before 11 pm last night and continuing this morning. The east lava pond and the other spatter cones glowed within Pu`u `O`o Crater overnight. The tiltmeter on the north flank of Pu`u `O`o cone recorded about 0.5 microradians of abrupt deflationary tilt coincident with the southwest spatter cone flow mentioned above followed by general weak deflationary tilt through this morning. GPS receivers on the north and south flanks of Pu`u `O`o cone recorded about 2 cm (to May 8) of extension since late-April along with elevated 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 continued with scattered activity 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