# Volcano Watch - Expansion of Alaskan Volcano monitoring program continues

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In one of the most ambitious volcano-monitoring efforts ever undertaken, scientists of the Alaska Volcano Observatory (AVO) are moving ahead with plans to increase the number of volcanoes they monitor with real-time geophysical instruments.

In the next few years, five more volcanoes in the westernmost Aleutian Islands will be rigged with new instruments using a ship as a base of operations--the first for mainland U.S. volcano observatories.

Alaska is home to one of the most formidable volcanic chains on Earth. More than 100 volcanoes extend westward 2,500 km (1,550 miles) from Cook Inlet near Anchorage to the Aleutian Islands and eastern Russia; 41 have erupted at least once in the past 240 years. The equivalent distance in Hawaii stretches from the Big Island to Midway and encompasses only four or five volcanoes, including submarine Loihi volcano, active during the same time.

In the past 15 years, many eruptions and periods of unrest at Alaskan volcanoes have affected cities and remote communities; the oil, power, and fishing industries; and, most importantly, commercial aircraft in the heavily traveled north Pacific air routes.

When AVO was established in 1988, only Augustine Volcano, 275 km (170 miles) southwest of Anchorage, was monitored well enough for scientists to provide effective warning of an impending eruption. Today, 23 volcanoes located as far as 2,050 km (1,275 miles) from Anchorage are monitored with 133 seismic stations.

AVO is a partnership between the U.S. Geological Survey, the University of Alaska in Fairbanks, and the Alaska Division of Geological and Geophysical Surveys.

Why such a focused effort to monitor Alaskan volcanoes?

In 1989, volcanic ash from the eruption of Redoubt Volcano nearly downed a Boeing 747 jet carrying 231 passengers. On December 15, the plane unknowingly descended into an eruption cloud 240 km (150 miles) downwind from the volcano, losing power in all four engines as gritty ash and sulfurous gas filled the aircraft. After gliding powerless for eight frightening minutes and falling 4,450 m (14,600 feet) toward the rugged Talkeetna Mountains, disaster was barely averted when the pilots restarted the engines and landed safely in Anchorage. Repair costs of the jet exceeded \$ 80 million.

The impact of Redoubt's eruption on aircraft safety ushered in a new era of volcano monitoring in Alaska. Even though most of the volcanoes are remote, more than 15,000 air passengers and millions of dollars of cargo pass over them daily. Since 1989, AVO scientists have worked closely with other federal agencies and the aviation industry to help aircraft avoid volcanic ash that can drift high in the atmosphere far downwind from an erupting volcano.

The key to reducing risk to aircraft was for AVO to increase the number of monitored volcanoes so that reliable warnings of impending activity could be given and the status of an ongoing eruption accurately determined. In 1996, with Congressional funding provided through the Federal Aviation Administration, AVO scientists began an aggressive effort to expand the monitoring program to active volcanoes in the Aleutian Islands.

Because of the remote locations of these volcanoes, AVO scientists have also built a very successful remote-sensing program using non-military satellite sensors. All volcanoes in Alaska and Russia are analyzed at least twice daily for signs of activity using images from several satellites. AVO is the only observatory that routinely utilizes near-real-time satellite data to detect unrest and eruptions for so many volcanoes.

This year, along with new seismic installations, AVO will begin installing continuously recording tiltmeters and GPS receivers on some volcanoes for tracking deformation caused by moving magma and faulting, borrowing from experience of its sister observatories, including the Hawaiian Volcano Observatory. Also, many geologists will continue to decipher the eruptive histories and hazards of Alaska's potentially dangerous volcanoes.

The hard and often risky work of many people affiliated with AVO has proven that the remote and dangerous volcanoes in Alaska can indeed be successfully monitored to reduce risk to people and property. Today's challenging plans will make the monitoring program even more robust and improve our understanding of this awesome volcanic chain.

### Volcano Activity Update

The eruption of Kilauea Volcano continued unabated at the Puu Oo vent during the past week. Intermittent lava activity was observed within the Puu Oo crater on January 21 and 22. Lava moves away from the vent toward the ocean in a network of tubes. Two major breakouts of the tube system at the 2,220-ft and 2,080-ft elevations have built small shields topped with lava ponds, which supply short surface flows. Other breakouts from the tube system supply surface flows on the pali and in the coastal flats. Lava is now entering the ocean only at Kamoamoa. The ocean entry east of Kupapa`u was found inactive on January 22, and geophysical measurements indicate that the feeder tube was empty.

The public is reminded that the bench of the ocean entry is very hazardous, with possible collapses of the unstable new land. The steam clouds are extremely hot, highly acidic, and laced with glass particles. Swimming at the black sand beaches of the bench can be a blistering or even deadly venture.

One earthquake was reported felt during the week ending on January 24. Residents of nearly every district on the island felt the earthquake originating from the south flank of Kilauea at 1:18 a.m. on January 18. The magnitude-4.1 earthquake was located 11 km (6.6 mi) west of Kalapana at a depth of 9.1 km (5.5 mi).