 Mountainous Eruptivity |
Mountainous Eruptivity |
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August 7, 2008
Arcticulates ®Focusing on Alaska's BeautyAuthor: K. FieldsMountainous-EruptivityView of Volcano Okmok's Recent Ash Plume
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-tops
I 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 yard, and if it is wet the weight doubles. I can see why it could collapse roofs. 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 for those who have any kind of lung problems. Which is why the local forestry departments (after a volcanic reaction) have handed out (free) the little masks they use in surgical rooms, encouraging people to wear them so it can prevent long term lung damage caused by breathing in the volcanic ash. Land-view Photo of Volcano Okmok's Recent Eruption
Another interesting thing about the volcanic ash is it can start out being ejected from the volcano as spray called liquid magma which as soon as air touches it, it will solidify into small fragments of glass. This ash is hard and abrasive, will not dissolve in water, and the most interesting thing is it conducts electricity (especially when it is wet) 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! Not a View I Want to See From an Airplane
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 Summit
Even 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. Ascending Eruption Cloud From Mt.Redoubt April 21, 1990
I have ended this with my favorite...Wait...is there such a thing as a favorite volcano? Later... K Fields See Also: A Traveling We Will Go!
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