USGS Volcano Hazards Program Volcano Update
Recent Observations at Kilauea summit: The summit tiltmeter network recorded slowing DI inflation that is now more than 4 microradians. The lava lake level also rose more slowly mimicking tilt. The most recent (preliminary) sulfur dioxide emission rate measurement was 700 tonnes/day on January 3, 2013; this value is a typical background emission rate between rise/fall events. A very small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair) was carried out of the vent in the gas plume and deposited on nearby surfaces.
Seismic tremor levels were low but quite variable in the morning. Five earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 2 within the middle east rift zone and 3 on south flank faults. GPS receivers located on opposite edges of the summit caldera recorded a small amount of extension over the past 2 days mimicking the tilt.
Background: The summit lava lake is deep 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 below the inner ledge (~31 m or 100 ft below the floor of Halema`uma`u Crater on October 29, 2012) and has not risen above and flooded the ledge since October 28, 2012. 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: Lava activity on the coastal plain continued to be weak. An approximately 1 km-wide (0.6 mi wide) lava flow remained active on the coastal plain with minor scattered surface activity near the coast straddling the easternmost boundary of Hawai`i Volcanoes National Park. Webcams recorded at least one sporadic ocean entry plume yesterday.
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.
The tiltmeter on the north flank of Pu`u `O`o cone recorded a little more than one microradian of inflation. Within Pu`u `O`o crater, glow was observed from the usual sources. GPS receivers on opposite sides of the crater recorded a small amount of extension mimicking tilt. Seismic tremor levels near Pu`u `O`o remained low. The most recent (preliminary) sulfur dioxide emission rate measurement was 250 tonnes/day on January 4, 2013, from all east rift zone sources.
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 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. 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 - The active 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, these flows 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 http://www.nps.gov/havo/planyourvisit/lava2.htm.
Update in Common Alerting Protocol (CAP) format