... MOUNTAINOUS ERUPTIVITY! ... |
Thursday, August 7, 2008~ MOUNTAINOUS ERUPTIVITY! ~Just
recently we have had another volcano called
Okmok Caldera erupt in
Alaska
sending a cloud of ash 35,000 feet (10.7 kilometers) into the air. This one was on the Aleutian chain - the last time it erupted was in 1997. A geophysicist reported ash burst up 50,000 feet... a mountainous eruptivity! This
was in a remote area, so they sent in a Coast Guard cutter (they could
not
send in an
aircraft because of falling ash and rock). They had to evacuate 9 people (included 3 children) who lived in the area. They were taken approximately 65 miles away to Unalaska (Dutch Harbor), a popular fishing port where the residents also reported seeing ash coverage. Image of the eruption of Okmok, Taken Sunday, July 13, 2008
There
are approx. 130 volcanoes and volcanic fields in Alaska. Seismic
activity is
monitored in real time at 30 volcanoes in Alaska. The volcanoes in Alaska make up well over three-quarters of U.S. volcanoes that have erupted in the last two hundred years. The plume of smoke over a volcano consists of ash and steam. This ashy dusty type stuff can be carried by the wind currents for miles and miles, eventually settling, causing a dust layer called an ashfall. Sweeping Volcanic Ash From Roof-topsI
still have some ash collected from outside our
home, when a volcano
(Mt.
Spurr) erupted
around 1992. I remember in some places ash was ½ inch thick or more, and it swirled around like a dust storm when cars were driving around. We could easily scrape a handful of ash off the car hood after it sat for a while. It was amazing! When Mt. Spurr had erupted for the third time, the next day when we looked outside, everything looked the same color; a thick layer of dark gray ash covered everything! So...recently
I found out that 4 inch thick ash can weigh 120-200 pounds per square I
looked up what volcanic ash consists of, and this
is what I
found: small bits of pulverized
rock and glass less than 2 millimeters (0.079 in) in diameter. Yikes!
We
breath that into our lungs when volcanoes erupt? That can’t
be
good! Especially Land-view Photo of Volcano Okmok's Recent EruptionAnother
interesting thing about the volcanic ash is it can start out
being
ejected from the So
that would explain why there can be problems with
short circuits,
and
electronic
components failing, like high voltage transformers which end up causing power outages This excerpt from: Alaska.edu/volcanoes is what concerns me the most. Last year we had to fly to Anchorage over a active volcano area, I felt a little nervous about it! “Alaska's
volcanoes are potentially hazardous to passenger and freight aircraft
as
jet engines sometimes fail after ingesting volcanic ash. On December 15, 1989, a Boeing 747 flying 240 kilometers (150 miles) northeast of Anchorage encountered an ash cloud erupted from Redoubt Volcano and lost power in all four jet engines. The plane, with 231 passengers aboard, lost more than 3,000 meters (~9,800 feet) of elevation before the flight crew was able to restart the engines (Casadevall, 1994). After landing, it was determined the airplane had suffered about $80 million in damage (Brantley, 1990). The series of 1989-1990 eruptions from Mt. Redoubt were the second most costly in the history of the United States, and had significant impact on the aviation and oil industries, as well as the people of the Kenai Peninsula. On the Kenai Peninsula , during periods of continuous ash fallout, schools were closed and some individuals experienced respiratory problems. At the Drift River oil terminal, lahars and lahar run-out flows threatened the facility and partially inundated the terminal on January 2, 1990 (Waythomas and others, 1998). The Redoubt eruption also damaged five commercial jetliners, and caused several days worth of airport closures and airline cancellations in Anchorage and on the Kenai Peninsula (Casadevall, 1994). Drifting ash clouds disrupted air traffic as far away as Texas. More information about the Redoubt 1989-1990 eruptions, including impact to people and infrastructure, is available here. The three eruptions of Mt. Spurr's Crater Peak in 1992 deposited ash on Anchorage and surrounding communities, closed airports, made ground transportation difficult, and disrupted air traffic as far east as Cleveland, Ohio." Volcano Augustine's New Lava Dome at The SummitEven
with all the hoopla on the dangers of volcanic eruptions, it can be
very interesting
living where active volcanoes are pretty common. It makes an interesting story to tell when talking about Alaska. I
have ended this with my favorite...Wait...is there such a thing as a
favorite volcano?
See Also: A Traveling We Will Go! Later...
K Fields
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