Science Fun

Our word for the week is Plucking, and this has nothing to do with plucking chickens. The term Plucking is a term related to Earth Science, and is a process of glacial erosion. Water beneath a glacier will freeze fragments of loose rock to the ice. When the ice moves, the rock fragment is “plucked” away from the underlying bedrock. Plucking is thought to be responsible for the formation of deep, jagged slopes such as the back wall of the corrie and the downslope-side of the roche moutonnee.

Word of the week is a regular feature on Science Fun and the ‘word’ is chosen by opening up my Big Book of Science Definitions and randomlly pointing the a word on the page.

Our word for this week is ‘Alexandrite’! Alexandrite is a mineral that appears to be different colors depending upon whether it is viewed in artificial light or in natural light. Alexandrite appears red when viewed by candle light and it appears blue to green when viewed under a fluorescent light.

The name ‘Alexandrite’ comes from when it was founded, which was on the birthday of the Russian Czar, Alexander II and it is named in his honor. Alexandrite is mined in Russia, Brazil, Burma, Ceylon, and Rhodesia. Laboratory produced alexandrite is common and is sold as natural alexandrite.

Some stones react to light in a fashion like alexandrite and this is known as the ‘Alexandrite Effect’ – a phenomena in which a stone appears different colors depending upon the light in which it is viewed. Garnet and Sapphire are two stones that exhibit this phenomenon. From Enchanted Learning science dictionary.

A few months ago, I posted a couple of articles on the Alsaka Volcano Redoubt when it was having its small eruption and a few after effects.  This activity was small compared to the explosive power of Mount St. Helens that had a major eruption on this day in history.

The date, May 18, 1980, a massive volcanic eruption of Mount St. Helens in southwestern Washington devastates 210 square miles of wilderness, leaving 57 dead or missing.  The volcano had erupted periodically during the previous years, with last active period prior to the 1980 explosion, being in the years 1831 through 1857.

The area around the volcano is slowly starting to heal as nature takes over with new growth.  Trails are open and the visitor centers are back in business as folks travel to visit the mountain.  While the mountain has not had any recent volcanic activity, the US Forest Service and the US Geological Service constantly monitor the area for any changes with cameras, sensors, and other measuring instruments.  The image is from a monitoring camera – taken on May 18, 2009 at 11:30 AM EDT.

Within the past month, I had written a post on the volcanic activity at Alaska’s Redoubt Volcano. It has been relatively quiet in the past few weeks, however, the Volcano Center continues to monitor the situation. As I was searching through my big science book, looking for an unusual word to share, I came across this one and it has something to do with volcano activity.

Our word for this week is nuee ardente, which is referring to the glowing white-hot cloud of gas and ash that is emitted by a volcano during a violent eruption. In 1902 a nuee ardente produced by the eruption of Mount Peter in Martinique swept down the side of the volcano within a matter of seconds and killed 28,000 people in the nearby town of St. Pierre.

On Saturday, March 21^st, Redoubt in Alaska become a little bit more active with venting of steam and some ash, this caused the Alaska Volcano Observatory to raise the level up to orange / watch and to issue some preliminary advisories.  Seismic activity was recorded by summit monitoring stations at the rate of about 26 per 10 minute intervals.

On March 22^nd at 22:38 AKDT the volcano erupted.  The threat level was raised to the highest which is now at: red / warning.  The initial cloud release was up to 50,000 feet above sea level.  Five explosions occurred during the initial eruption period between the evening of March 22^nd and around 5:00 AM AKDT on the 23^rd.  The National Weather Service has reported ash clouds reaching as high as 60,000 feet with the bulk of the ash between the 5,000 and 20,000 foot mark.  This eruption caused melting of the Drift glacier and as a result has caused the water level in Drift River to rise. 

Another round of ash eruption occurred again on the evening of March 23^rd around 7:40 PM ADT.  This could was estimated to reach around 50,000 feet and lasted just under 20 minutes.  Seismic activity has diminished somewhat since the start of the initial eruption event on Saturday.  There was little activity on the 24^th and an over flight as well as satellite images showed steam rising to around 20,000 feet and drifting about 40 miles northwest.  On the 25^th, a small explosion occurred around 5:10 AM AKDT and the event lasted for around 10 minutes. 

Volcano Redoubt has been relatively quiet in recent years, up until the Fall of 2008 when seismic activity started to increase.  This volcanic unrest with the mountain intensified in January and has continued to escalate over the past weeks until the small eruption that occurred earlier last week.  The volcano alert condition remains at red / warning and other eruptions and events can occur at anytime without warning. 

The Alaska Volcano Observatory is staffed 24 hours a day and is continuing to monitor the status of the volcano.  You can get updates via the National Weather Service: http://pafc.arh.noaa.gov/volcano.php.  The observatory is also feeding updates by Twitter and you can follow along here: http://twitter.com/alaska_avo.

If you remember, Mount St. Helens went through its period of eruptions, you can read up on it by checking out the book review on “Super Volcano” over at Nonfiction Book Review.

While at work today, I received a news alert about a volcano having some activity, I thought at first that it was Redoubt in Alaska as I had written a post on it earlier in the week.

A volcano erupted under the Pacific ocean, sent ash and debris over a 1,000 feet into the sky. This eruption process began late on Monday and continued on through until Wednesday when enough lava had flowed out that a new island had been formed in the Pacific. This volcano is one of 36 that comprise the”Ring of Fire” in the Pacific

This volcanic eruption occurred in the South Pacific, about six miles off the coast of Tonga’s main island, Tongatapu. Residents of the island reported seeing the eruption from the ocean on Wednesday, even though scientists indicated the eruption began on Monday. As of this evening, no warnings and advisories have been issued to the island residents as the volcanic eruption is far enough away that there is minimal impact. The trade winds are also helping as they are blowing the steam and gas from the eruption away from the islands.

The U.S. Geological Survey has indicated that a 7.9 magnitude earthquake occurred and this has prompted the Pacific Tsunami Warning Center to issue a tsunami warning for neighboring islands (as of this posting, it was not certain a tsunami has occurred.) The U.S. Geological Survey has indicated the possibility of a rise in sea level along the coast of Hawaii.

photo from Reuters News Agency