Volcano Watch — Volcanologists Work the Night Shift Watching Halema`uma`u's New Vent

HVO started a 24-hour watch a few days after the first explosion at Halema`uma`u four months ago. Since then, each person on night watch sits in the tower with a clear view of Halema`uma`u and with computers, binoculars, cameras (time-lapse, camcorder, and webcam), a phone, and emergency procedure documentation watching the activity. If something different from the usual happens, he or she makes an initial assessment and calls the Scientist-in-Charge (SIC).
Watching the activity means following many data feeds including seismicity and surface deformation. For HVO, it also means making visual observations about the brightness of the vent, ejected material, color and density of the plume, and any other changes.

When watching the computer data feeds, the ability to "see" what is going on depends on the type, placement, and amount of monitoring equipment on the volcano. Kīlauea has a variety of monitoring instruments by which to collect data on the eruptive activity which yields an excellent instrumental view of what is happening.

HVO is just one of several volcano observatories operated by the U.S. Geological Survey. If activity at one of the U.S. volcanoes changes dramatically - for example, if a new vent opens and deposits ash on a frequently used parking lot (as Halema`uma`u did on March 19) - the scientists at that observatory make sure someone is on watch 24 hours a day.

If the 24-hour watch continues for more than a week, scientists from other USGS observatories and centers fly in to help out with the night shift. Getting help from the other observatories gives the local observatory personnel time to focus on analyzing the data and distributing information and assessments to the public.

Each visiting scientist works for 16 nights straight, providing coverage for one third of each 24-hour watch. He or she overlaps with the previous visiting scientist on the first night and passes on information to the next scientist on the last night. At each shift change, summaries are provided and observations logged. The new shift person reviews the data from the past day and compares it with data from the previous week or months to look for trends, then begins making his or her own observations.

During times of increased activity, there are many opportunities to discuss observations and share theories. Summary meetings are held weekly. In these meetings, scientists present information on recent earthquakes, ground movement, vent temperatures, gas contents, lava flows, and plume observations. The data are also available to our colleagues at other observatories who share their expertise and perspectives, based on the volcanoes they monitor.

Although each volcano is different and the observatories have different needs, the night shift goal is the same: you watch the volcano so others on the staff can sleep. In the past four years, night shifts have been manned for Mount St. Helens at the Cascades Volcano Observatory (CVO) in Vancouver, WA, and for Augustine at the Alaska Volcano Observatory (AVO) in Anchorage, AK.

HVO isn't the only U.S. volcano observatory currently monitoring new activity. Last week, Okmok volcano in the Aleutian Islands, started to erupt. With little warning, the volcano sent a plume of ash up to 15 km (50,000 ft) in the air. That's almost eight times higher than the 2 km (6,500 ft) height of the Haleama`uma`u plume, as reported by the Washington Volcanic Ash Advisory Center (VAAC) on March 25th.

Then on Monday, July 21st, reports came in that Mt. Cleveland, 144 km (90 miles) west of Okmok volcano, was erupting. AVO monitors Mt. Cleveland with satellite imagery as weather allows. There is no real-time seismic network at Cleveland, so explosions of ash exceeding 6 km (20,000 ft) can occur without warning. Unlike HVO, where the SIC can look out his window at the caldera, the AVO SIC sits in Anchorage, AK over 1,440 km (900 miles) away from Mt. Cleveland. Who knows - if the activity continues, maybe AVO will request night-shift help.

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Volcano Activity Update

Kīlauea Volcano continues to be active. A vent in Halema`uma`u Crater is erupting elevated amounts of sulfur dioxide gas and very small amounts of ash. Resulting high concentrations of sulfur dioxide in downwind air have closed the south part of Kīlauea caldera and produced occasional air quality alerts in more distant areas, such as Pahala and communities adjacent to Hawai`i Volcanoes National Park, during kona wind periods.

Pu`u `Ō`ō continues to produce sulfur dioxide at even higher rates than the vent in Halema`uma`u Crater. Trade winds tend to pool these emissions along the West Hawai`i coast. Kona winds blow these emissions into communities to the north, such as Mountain View, Volcano and Hilo. Incandescence continues to be observed at night inside Pu`u `Ō`ō and suggests minor activity from vents on the crater floor.

Lava continues to erupt from fissure D of the July 21, 2007, eruption and is supplying minor breakouts along the 2007 Thanksgiving Eve Breakout (TEB) tube system on the pali within Royal Gardens. No significant breakouts have been observed this week in the vicinity of the TEB shields.

Lava also continues to flow through what remains of Royal Gardens and across the coastal plain to the ocean in a well-established lava tube active now for several months. Explosive activity at the Waikupanaha ocean entry has diminished over the past week. New breakouts have recoated the delta with fresh lava, creating a broad entry area.

Be aware that lava deltas could collapse at any time, potentially generating large explosions. This may be especially true during times of rapidly changing lava supply conditions, as have been seen lately. Do not venture onto the lava deltas. Even the intervening beaches are susceptible to large waves generated during delta collapse; avoid these beaches. In addition, steam plumes rising from ocean entries are highly acidic and laced with glass particles. Check Civil Defense Web site or call 961-8093 for viewing hours.

Mauna Loa is not erupting. No earthquakes were located beneath the summit this past week. Continuing extension between locations spanning the summit indicates slow inflation of the volcano.

Three earthquakes beneath Hawai`i Island were reported felt within the past week. A magnitude-2.9 earthquake occurred at 9:53 p.m. on Saturday, July 19, 2008, H.s.t and was located 5 km (3 miles) southeast of Pu`u `O`o Crater at a depth of 8 km (5 miles). A magnitude-2.4 earthquake occurred at 8:06 p.m. on Wednesday, July 23, and was located 13 km (8 miles) northwest of Kawaihae at a depth of 29 km (18 miles). A magnitude-2.5 earthquake occurred later that same day at 11:52 p.m. and was located 47 km (29 miles) northwest of Kailua at a depth of 6 km (4 miles).

Visit our Web site for daily Kīlauea eruption updates, a summary of volcanic events over the past year, and nearly real-time Hawai`i earthquake information. Kīlauea daily update summaries are also available by phone at (808) 967-8862. Questions can be emailed to askHVO@usgs.gov. skip past bottom navigational bar