Volcano Watch — World's Active Volcanoes Keep Scientists Busy in 2008

Such a review reminds us that volcanoes have a way of changing the course of lives and livelihoods with little or no warning in persistent and pervasive ways.

The significant events at Kīlauea during 2008 included a new eruption at Halema`uma`u Crater (the longest summit eruption since 1924!), lava entering the ocean following the July 21, 2007, fissure eruption downrift of Pu`u `Ō `ō, and dramatic increase in the emission of sulfur dioxide gas from the new Halema`uma`u and old Pu`u `Ō `ō vents.

The increased gas emission seriously affected or killed nearby agricultural crops, led to restricted public access in Hawaii Volcanoes National Park, and engulfed thousands more people than "usual" for brief but numerous periods of time.

The new lava entry area, however, provided tens of thousands of people with safe viewing experiences of lava flows and small explosions along the coast thanks to the hard work of Hawai`i County and it's Civil Defense staff.

Worldwide an average of about 60 volcanic eruptions occurs each year based on eruption records of the past 20-30 years. A Weekly Volcanic Activity Report supported by the Smithsonian Institution's Global Volcanism Program and the U.S. Geological Survey is a good source of preliminary information of the world's volcano activity.

A review of these preliminary reports shows that about 84 volcanoes either erupted or showed signs of restlessness in 2008. Forty-eight of these volcanoes were active sometime during 2007, including Kīlauea.

Sixteen volcanoes erupted or were restless in Indonesia, 8 in the United States, 7 each in Japan and Russia, and 6 each in Ecuador and Papua New Guinea.

Two of the most explosive eruptions occurred at volcanoes that were not monitored, Chaitén Volcano in Chile and Kasatochi in Alaska. Kasatochi hadn't erupted in more than a century; Chaitén hadn't erupted in more than 9,000 years.

The May 2nd eruption of Chaitén greatly affected people living in the area and neighboring Argentina because of significant ash fall and lahars. Residents of the remote coastal town of Chaitén (pop. 4,700), located 10 km (6 miles) from the volcano, were evacuated within days. The town was the gateway for tourism in Patagonia and a center of commercial salmon aquiculture, but within 2 weeks, a thick accumulation of ash and heavy rainfall led to lahars (volcanic debris flows) and sediment-laden floods that buried parts of the town and airport.

At the end of 2008, Chaitén was still erupting a new lava dome in its crater and generating frequent ash columns 2-3 km (6,500-9,850 feet) high. Chileans are still working to decide the fate of the town and former residents.

Kasatochi erupted first on August 7, resulting in an enormous ash and gas cloud that spread southeastward across the Gulf of Alaska, Canada, and the northern United States. Many airlines diverted or cancelled flights to avoid the volcanic cloud. On August 10, dozens of cancelled flights in the Western U.S. stranded more than 6,000 passengers.

In Colombia thousands of people living in river valleys draining the glacier-covered Nevado del Huila volcano had to evacuate their communities in April because of increased activity detected by scientists and again in November because of an eruption. Hot material erupted onto the summit November 20, melting some of the glacier and generating lahars as high as 10 m (33 ft) in two river valleys.

Colombian scientists monitoring the volcano had raised the warning levels and good communications with the communities downstream of the volcano resulted in fewer than 10 casualties. Similar lahars that occurred in 1994, triggered by a large earthquake and landsliding, killed more than 1,000 people.

The Hawaiian Volcano Observatory wishes a safe new year for scientists and other volcano watchers across the globe tracking the world's volcanoes. We especially wish this for people and communities living on or in the shadow of a volcano active during the past few years or that becomes active and erupts in 2009.

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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, while Kona winds blow these emissions into communities to the north, such as Mountain View, Volcano, and Hilo.

Lava erupting from the Thanksgiving Eve Breakout (TEB) vent at the eastern base of Pu`u `Ō`ō continues to flow to the ocean at Waikupanaha through a well-established lava tube. Beakouts from the lava tube were active in the Royal Gardens subdivision and on the coastal plain in the past week. Ocean entry activity has continued throughout the past week, with a minor short-term reduction in activity following a deflation-inflation cycle on December 27.

Be aware that active lava deltas can collapse at any time, potentially generating large explosions. This may be especially true during times of rapidly changing lava supply conditions. The Waikupanaha delta has collapsed many times over the last several months, with three of the collapses resulting in rock blasts that tossed television-sized rocks up onto the sea-cliff and threw fist-sized rocks more than 200 yards inland.

Do not approach the ocean entry or 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. Call Hawaii County Civil Defense at 961-8093 for viewing hours.

Mauna Loa is not erupting. Four earthquakes were located beneath the summit this past week. Continuing extension between locations spanning the summit indicates slow inflation of the volcano, combined with slow eastward slippage of its east flank.

One earthquake beneath Hawai`i Island was reported felt within the past week. A magnitude-3.1 earthquake occurred at 1:39 p.m., H.s.t., on Sunday, December 28, 2008, and was located 5 km (3 miles) southeast of Pahala at a depth of 9 km (6 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.