Volcano Eruption Warning Sign

Volcano watchers raise alert status for Mount Cleveland

The Alaska Volcano Observatory reports "disturbing increase or escalation" and the possibility of an eruption of the volcano 5676 meters, depending on the site of the observatory.

Cleveland Volcano includes the western half of the island Chuginidak, which is about 115 miles west of Dutch Harbor and 950 miles southwest of Anchorage.

Satellite data and visual observations at the end of July revealed a lava dome about 140 feet in diameter growing in the crater of the volcano, said volcanologist Chris Waythomas. The dome grew another 10 feet or so between Tuesday and Wednesday, according to the observatory.

"Sometimes lava domes like that can be explosive and lead to ash production," Waythomas said.

The volcano observatory raised the advisory status from "advisory" to "watch" and the aviation warning level from yellow to orange.

Cleveland is capable of blasting volcanic ash more than 20,000 feet into the sky -- a significant danger to air traffic in the vicinity -- so staff at the observatory decided to warn aviators of a possible explosive eruption, the researcher said.

Still, it's not certain that any ash-producing eruption will occur, Waythomas said.

"This could be the end of a little pulse of magma that's come into the volcano to form a little dome in there, and that'll be that, or it could lead to something more explosive," he said.

Because of a lack of seismographic equipment at the volcano, researchers must rely on pilot observations, satellite data and a webcam sometimes obscured by clouds, Waythomas said. An eruption could occur with little or no warning, he said.

Planes flying across the North Pacific Ocean or locally between islands would have to avoid the ash cloud, Waythomas said.

The most up-to-date information on Cleveland Volcano can be found at www.avo.alaska.edu .

Reach Casey Grove at casey.grove@adn.com or 257-4589.

Recent Volcanic Activity and Impending Eruptions « End Times Signs

Italy - Stromboli is stirring. This marks the first effusion of lava from the terrace outside the crater since the issuance of a small lava flow on the night of 11-12 December 2010. Around 2100 GMT, Aug. 1, a vast accumulation of incandescent material appeared at the base of the vent N1, the northernmost of several active vents that are located in the crater terrace about 750 m above sea level on Stromboli. A few minutes later, this material started to collapse and slide, and then developed two small lobes of lava, the more easterly of which descended slowly on the steep slope of the northern portion of the Sciara del Fuoco, repeatedly generating collapse and small landslides derived from the loose material that the slope is made of. The lava then accumulated on the flat area where the hornitos of the 2002-2003 eruption had been located, before making its way down the steep slope below that flat area (as is shown in the two bottom frames in the figure above).In the late morning of August 2, the lava flow had dropped to about 500 m above sea level and moved very slowly. During the early afternoon the same day, feeding the lava flow appeared to decrease. This lava flow is the first major summit to overflow Stromboli decades, the most recent event is similar to the eruption of November 1975. During the subsequent eruptions in 1985-1986 and 2002-2003, the outpouring of lava occurred from eruptive fissures on the upper slope north of the Sciara del Fuoco, while in 2007, the vent main effusive was located 400 m above sea level. Differently from these eruptions, the usual Strombolian activity from the summit craters has not ceased with the onset of lava effusion on 1-2 August 2011. – CT.Ing.It

Russia – The Kamchatka Peninsula, along Russia’s Pacific coast, is currently the most volcanically active area in the world: four volcanoes are erupting simultaneously, and a fifth is showing signs of an impending eruption. Ash plumes from two of these volcanoes are visible in this natural-colour satellite image. Along the northern (top) edge of the image Shiveluch emits a broad gray plume from the lava dome growing on its southern flank. 90 kilometres (60 miles) to the southwest a much smaller plume escapes from Bezymianny. This image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite on August 3, 2011.

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