Active volcanoes / Aktive vulkaner:

Veniaminof, Alaska

Eruption activity from the top of Veniaminof.
Photo: B. Yount, U.S. Geological Survey, July 26, 1983.

Veniaminof is in Alaska, situated about 56°10' N og 159°22.48' W, that is 775 km SW of
Anchorage, and it raises 2,507m asl. Veniaminof is a large stratovolcano
in which a large caldera was formed during an eruption about 3.700 years ago. The caldera is
about 10 km wide, filled with snow and ice. All previous eruptions have come from vents in the
snow and ice. When lava comes out, it has often been flowing down upon the snow or ice, and
then melted it during its way further out in the caldera, and a lavalake developes.

Historic eruptions from the volcano has made vapour and ashcolumns as high as 6.000 m above
the summit, and ash has covered areas within 40 km radius.

Vapour from a vent on Veniaminof during the last part of the eruption in
av utbruddet 1983-1984. Not so hot lavastreams fill up an area of 2,3 x 1,0 km which
has been melting the underlayin ice- and snowcover..

Photo: B. Yount, U.S. Geological Survey, January 23, 1984.

Only few people live near the volcano, so chances for loss of human lives are small.
Still they oucht to be frightened if a so called jökulhlaup (See Grimsvötn) comes. A
jökulhlaup is the result when an eruption comes under a thick layer of ice or snow. The eruption
will then melt the lower part of the icecover. If this last long, the icecover above will flow upon its
own melted water. When such a situation occurs, melted water will slip away and a tremendous
flow of water will flow down the slopes of the volcano, destroying everything on its way.
This often happens on Oceland, and such a possibility might also come to Veniaminof.

Tuesday, January 11th, 2005
Ash emissions from the intracaldera cone of Mount Veniaminof, some reaching nearly
13,000 ft (3692 m) above sea level, have occurred more or less continuously over the
last 48 hours. Seismicity remains at elevated levels and satellite images show a persistent
thermal anomaly in the vicinity of the cone. Thus the color code for Mount Veniaminof has
been upgraded to ORANGE.

Very weak volcanic tremor was observed starting on January 1, 2005. Since then, the magnitude
of the volcanic tremor has increased significantly and there have been frequent (> 1 per minute)
small volcanic earthquakes. As of this writing, seismic activity is nearly continuous; the frequency
of seismic events exceeds that recorded during steam emissions and ash emissions from April to
October, 2004, however the overall amplitude remains about the same. We expect that steam
and ash emissions may continue and could pose a hazard to people and low- to medium-flying
aircraft in the vicinity of the active cone.

Thursday, January 6th, 2005

Weak seismic tremors were observed starting Jan. 1 and increased slightly over the next
few days. Ash emissions were observed in images of Veniaminof taken around 9:30 a.m.
Tuesday. At around 10 a.m. Tuesday a pilot flying at 14,000 feet noted small ash
emissions from Veniaminof.

Later in the day, 19 separate ash bursts were observed from Veniaminof, none of which
escalated above 500 meters from the summit. The most recent reports from Perryville
included constant ash emissions today at around 10 a.m.
From Kodiak Daily Mirror

Saturday, July 31st, 2004
Episodes of volcanic tremor continue intermittently at Mount Veniaminof Volcano. No
visual observations of ash emissions have been made since July 22, (picture below)
although the observed seismicity is similar to that observed coincident with ash
emissions in the past few months. Most such emissions do not reach 10,000 ft. above
sea level, though a few have been reported to reach as high as 12,000 ft.

Tuesday, May 4th, 2004

Active web-camera: See our web-cam site here

Mount Veniaminof has been restless over the past week, spitting up ash and steam, and lightly shaking the ground, according to the Alaska Volcano Observatory.
"We expect that steam and ash emissions similar to those observed this week may continue intermittently and could pose a hazard to people and low-flying aircraft in the vicinity of the active cone," the observatory reported in its Friday update.

Ash and steam spotted during clear weather last Wednesday and Thursday rose to 8,000 to 10,000 feet above sea level. The clouds then drifted 10 miles on strong winds, while seismic tremors continued above background levels.

April 27th, 2004
During 10-17 April, Veniaminof showed heightened seismicity with several episodes of
volcanic tremor and earthquakes. Seismicity decreased significantly prior to the emission
of a gas plume with some ash throughout 18 April. The most vigorous phase occurred
at about 1730 on 18 April when the plume rose to ~0.5 km above the crater.
At about 1130 on 19 April another period of heightened seismic activity began.
Due to the increased activity, Veniaminof was upgraded to Concern Color Code Yellow.

Strombolian eruption with hot lava fragments from the top of Veniaminof.
Photo: B. Yount, U.S. Geological Survey, July 13, 1983.



over 250


over 500


over 225

    alfabetisk liste
    alphabetic list

Free Counter
Denne siden er laget ved hjelp av Macromedia Dreamweaver