Natural Hazards - Volcanoes

Recent Volcano Observatory Activity Reports

• Redoubt Status Report issued Nov 10, 2008 11:47 ADT Volcano Alert Level ADVISORY - Aviation Color Code YELLOW
  Seismicity remains low at Redoubt Volcano. Satellite views of the volcano were cloudy with no activity observed.

• Okmok Status Report issued Nov 10, 2008 11:47 ADT Volcano Alert Level ADVISORY - Aviation Color Code YELLOW
  Seismic activity at Okmok Volcano remains low. Satellite views of the volcano continue to be cloudy with no activity observed.

• HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE issued Nov 10, 2008 07:41 HST Volcano Alert Level WATCH - Aviation Color Code ORANGE
  This report on the status of Kilauea volcanic activity, in addition to maps, photos, and webcam images (available using the menu bar above), 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. Hawai`i County Viewing Area status can be found at 961-8093. Activity Summary for last 24 hours: No significant changes have occurred. Sulfur dioxide emission rates from the Halema`uma`u and the Pu`u `O`o vents remain high. Tephra production from the Halema`uma`u vent remains small. At the east rift eruption site, lava flows through tubes to the ocean; surface flows are active on the pali. Last 24 hours at Kilauea summit: Overnight, the vent glow is rarely visible and too weak to be recorded by the webcam. This morning, weak winds allow the plume to rise high over the crater rim before moving WSW over the Ka`u Desert. Sulfur dioxide emission rates remain elevated and variable. The most recent average measurement was 900 tonnes/day on November 7, compared to the 2003-2007 average rate of 140 tonnes/day. Variable but small amounts of tephra, mostly ash-sized spatter, continue to be produced and deposited downwind of the vent; during this morning's collection, sounds were muted with the distant surf sounds and small rockfalls still being heard. Kilauea caldera continues slow deflation. The network of tiltmeters within the caldera recorded minor oscillations with steady, weak, inward tilting. The GPS receiver networks (less sensitive than tiltmeters) recorded weak contraction (barely 1 cm per month). Seismic activity continued at low levels focused on the south caldera; tremor levels were at moderate values. A total of 9 earthquakes were located beneath Kilauea or nearby, including 5 beneath the south caldera and none on south flank faults, with the number of RB2S2BL earthquakes beneath the caldera at background values around 30-40/day. Last 24 hours at the middle east rift zone vents and flow field: Magma continues to degas through Pu`u `O`o Crater. The most recent sulfur dioxide measurement of 2,000 tonnes/day on November 7 compared to the 2003-2007 average of about 1,700 tonnes/day for this vent. No incandescence was observed within the crater overnight. The tiltmeter on the north side of Pu`u `O`o recorded weak deflation. GPS stations spanning the crater (less sensitive than tiltmeters) recorded about 4 cm of contraction over the past 3 months. Seismic tremor levels near Pu`u `O`o and the TEB vent remain at low values. Lava from the TEB vent and the rootless shield complex flows through tubes to the ocean. Last night, CD officials reported business as usual with an active ocean entry and continuing surface flows on the pali. No incandescence was seen overnight from the east rift eruption site to the top of the pali. Thermal anomalies seen in GOES-WEST imagery overnight appeared weaker than over the past several days suggesting surface flow activity may have diminished. Definitions of terms used in the update: FLIR: Forward Looking InfraRed, a camera which directly images heat rather than visible light. If volcanic fume is not too rich in water vapor, a FLIR can see through it to image hot surfaces. pali: Hawaiian word for cliff or steep incline. In the context of the TEB flow field, 'pali' usually refers to Pulama pali that bisects the abandoned Royal Gardens subdivision. CD: Hawai`i County Civil Defense DOH air quality monitoring: see Hawai`i State Department of Health Air Quality website http://hawaii.gov/doh/air-quality/index.html . bomb: lava fragment ejected into the air while molten acquiring aerodynamic shapes in flight; the term is restricted to pieces larger than 6.4 cm (2.5 in.). See http://volcanoes.usgs.gov/Products/Pglossary/bomb.html hybrid, or explosion, seismic signals: complex earthquakes that are a hybrid of different signals. They start as a high frequency earthquake, similar to typical rock-breaking or rock fall events, that transitions to very long, 20-30 second, period (VLP) oscillations that continue for several minutes. At HVO, we observed these signals with the four small Halema`uma`u explosive eruptions in March, April, and August 2008. Several more similar signals, some as strong as the explosion signals associated with the four explosive eruptions, have been recorded without obvious evidenceof surface eruption such as rock fragments or other debris. MODIS satellite: a NASA satellite pair, Aqua and Terra, which passes over Hawai`i twice a day. During daylight hours, the images are taken at about 11 am and 2 pm H.s.t. This imagery can be viewed about 3-5 hours after acquisition at http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=AERONET_Mauna_Loa. GOES-WEST satellite: a geostationary NOAA satellite used most often for weather tracking. Images are typically acquired every 15 minutes. The loop http://www.ssd.noaa.gov/VAAC/kilauea/sloop-vis.html is posted by the Washington DC Volcanic Ash Advisory Center for the purpose of tracking emissions from Hawai`i volcanoes. The imagery automatically switches from infrared at night to visual during the day. Recently, it has been useful for tracking volcanic gas emissions from Halema`uma`u, Pu`u `O`o, and the Waikupanaha ocean entry during the day and hot lava flows at night. Volcano Watch: weekly newspaper-like article written by HVO scientists on a volcano topic of interest. These articles are usually printed in the Sunday editions of the Hawai`i Island newspapers Hawaii Tribune Herald and West Hawaii Today. More than 800 of these articles have been written and are archived on the HVO website (menu at the bottom of the homepage hvo.wr.usgs.gov). VLP seismic tremor: seismic tremor is continuous ground vibrations simultaneously at many different frequencies. VLP is a very long period or very low frequency component which, at the Halema`uma`u vent, has a period of 20-30 seconds or a frequency of 0.03-0.05 cycles per second (Hertz or Hz). RB2S2BL earthquakes: earthquakes that were recorded but too small to be located. These quakes have magnitudes less than 1.7 and may only be recorded on one or two seismometers. Recording at a minimum of 4 seismometer sites is required to locate an earthquake. wink: an abrupt shutting off of incandescence at a vent lasting for several minutes. At the Halema`uma`u vent, winks usually start with or immediately follow a small, local earthquake. The diminishment of incandescence is due to the plume changing from translucent to opaque with rock dust. tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons. microradian: a measure of angle equivalent to 0.000057 degrees. ppm: parts-per-million; 10,000 ppm = 1 %. littoral cone: usually small cones built near active ocean entries; the cones are constructed of tephra from steam explosions that are sometimes produced when 1,150 degree C lava enters the 25 degree C ocean. incandescence: the production of visible light from a hot surface. The color of the light is related to the temperature of the surface. 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). 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. TEB: Thanksgiving Eve Breakout, the designation used for lava flows that started with a breakout on November 21, 2007. DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a volcanic event of uncertain 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 to 2-3 days 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 eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o, delayed by 1-2 hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/July 21/TEB vents. Maps, photos, webcam views, and other information about Kilauea Volcano are available at http://volcano.wr.usgs.gov/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://tux.wr.usgs.gov/ A definition of alert levels can be found at http://volcanoes.usgs.gov/2006/warnschemes.html

• LONG VALLEY OBSERVATORY CURRENT STATUS REPORT issued Nov 10, 2008 08:53 PST Volcano Alert Level NORMAL - Aviation Color Code GREEN
  There were no earthquakes large enough to be located by the real-time detection system in the Long Valley area since the last update at 12:07 PM on Sunday, November 9.