Volcano Update from Archive
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
Activity Summary: No significant change. Kilauea continued to erupt at its summit, where weak inflation and slow rising of the lava lake continued, and in the middle east rift zone, where the Pu`u `O`o vent fed two lava flows: to the northeast, the Kahauale`a lava flow continued to be active over older Pu`u `O`o flows and, to the southeast, the Peace Day flow was entering the ocean in two main locations spanning the National Park boundary. Gas emissions remained elevated.
Recent Observations at Kilauea summit: After being stable for the previous 24 hours, the summit tiltmeter network recorded slight inflation after noon yesterday and the lava lake continued to rise slowly reaching levels of about 31 m (100 ft) below the floor of Halema`uma`u Crater this morning. The most recent (preliminary) sulfur dioxide emission rate measurement was 700 tonnes/day on March 5, 2013; this value is within the range of higher emission rates during periods when lava sinks are spattering on the lake surface; new measurements must await the return of moderate trade winds. 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 - tremor values and SO2 concentrations near the vent sporadically dropped to near-zero values when spattering was largely absent suggesting that most of the gas releases through spattering. Five earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 1 south of the summit caldera, 2 within the upper east rift zone, and 2 on south flank faults. Since mid-February, the GPS receivers located on either side of the summit caldera have recorded short periods of extension and contraction across the summit area, mimicking the summit DI tilt events, but no significant longer-term trend.
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 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. 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: Within the Pu`u `O`o crater, the usual four spatter cones on the crater floor continued to glow at night. The tiltmeter on the north flank of Pu`u `O`o cone continued to record weak inflation. Seismic tremor levels near Pu`u `O`o remained low. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on March 4, 2013, from all east rift zone sources; these values have typically been between 200 and 300 t/d from November through January and 200-400 t/d through February. Two lava flows (Peace Day and Kahauale`a) were fed by lava tubes extending from Pu`u `O`o:
Peace Day lava flow activity on the pali and the coastal plain continued in several areas with no significant changes - a patch of active breakouts just above the pali about 5 km (3 mi) southeast from Pu`u `O`o (visible in occasional satellite images but not in our Webcams) that are visible from the Kalapana Viewing Area, and several branches on the coastal plain. The main branch of the Peace Day flow continued to enter the ocean at two main locations (inside and outside Hawai`i Volcanoes National Park); the ocean entry plumes were blowing to the southeast along the coast this morning. A flow branch to the west was active in scattered locations between the base of the pali and the mid-coastal plain (visible in mobile cam 2).
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 Kahauale`a flow remained active along the north base of the 2007 perched channel over older flows from the 30-year ongoing eruption and advanced more than 4 km (2.5 mi) to the northeast from Pu`u `O`o in the most recent satellite image acquired this past Saturday; based on its advance rate last week, the flow could have advanced another kilometer to the northeast by this morning. The flow continued to advance over 1980s-vintage Pu`u `O`o lava flows but was nearing the edge of those flows and forest within the Wao Kele o Puna land parcel this morning.
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 started from the spatter cone/lava lake at the northeast edge of the Pu`u `o`o crater floor in early February, 2013, and advanced north to the base of the cone before turning to the northeast and splitting at the base of the 2007 perched channel. 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 http://www.nps.gov/havo/planyourvisit/lava2.htm.
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php
Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.
A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/
HVO Contact Information:
Definitions of Terms Used:
DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.
fill-and-drain, rise/fall cycles/events or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake in starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward. In 2013, the character of these events has changed and are marked more by a lack of spattering sinks and less by a rise in lava level or tilt change during the low seismic tremor levels.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).
pali: Hawaiian term for cliff or precipice.
composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.
Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.
glow: light from an unseen source; indirect light.
incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.
The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.