Elaine Meinel Supkis
The dome in Mt. St. Helens is growing and in the middle of the dome is a sharp nearly rectangular rock that is shooting straight up. Many of the world's volcanoes are troubled by recent tectonic plate events.
John Roach
for National Geographic News
May 9, 2006
A massive fin-shaped slab of hot rock has recently been seen growing in the crater of Washington State's Mount St. Helens.The feature is the seventh such structure to rise in the volcano's crater since it began slowly erupting in October 2004, say scientists with the U.S. Geological Survey's (USGS) Cascade Volcano Observatory.
"This one has created a stir, in part because it began to emerge in the dead of winter—in the middle of November '05," said Daniel Dzurisin, a volcanologist at the Vancouver-based observatory who studies the dome."It was a particularly snowy winter in the Northwest. We didn't get many views, and we hadn't seen this feature before recently."
The newest creation currently stands about 300 feet (90 meters) tall and is 330 feet (100 meters) wide at the base, Dzurisin says.
The feature is growing at a rate of 4.6 feet (1.4 meters) a day.
Here is a video of the rock emerging from the lava dome.
Evidently, this is a fairly steady mountain building that is different from the Hawaiian volcanoes, the Cascade system is quite different. "Hot spot" volcanism is less likely to be hyper-explosive unlike subduction volcanoes. This week the subduction chain the ties Siberia to Russia have been having minor eruptions and earthquakes, the latest a 6.3 event on Fox Island. Then today, another 6.2 event at Kamchatka, Russia.
I want to thank Marty Salo for sending emails about these events.
Mt. St. Helens is of great interest to Americans since it is on our continent. But the one that can alter the weather world-wide as well as rearrange the landscape extensively are the Indonesian volcanic chain and the most active volcano this cycle is Mt. Merapi.
Geologists said that Merapi was continuing to show increasing activity. On Tuesday, a total of six shallow volcanic temblors were recorded compared to two a day earlier, while there were 152 quakes caused by lava movements compared to 102 the previous day.A new lava dome at the peak of Mount Merapi was continuing its rapid growth but Muzani from the vulcanology office in Yogyakarta, some 30 kilometers (18 miles) south of the volcano, said it was still stable.
A collapse of the lava dome would send lava and deadly heatclouds speeding down the slope, geologists have warned, rather than a massive explosion.
During the middle of the last century, volcanoes were pretty inactive. This is starkly different today. The last 20 years has been a bonanza for students of volcanoes. I am betting it is going to be increasingly interesting.
I like the cartoon! Geology is very sexy: all that thrusting... and grinding... and slipping... and sliding...
There's an interesting article about supervolcanoes in the June issue of Sci Am. I'll send a link when it becomes available - the website trails the print edition by a few weeks.
Posted by: JSmith | May 12, 2006 at 09:39 AM
The USGS sites with earthquake RSS feeds make it easy to be aware of the activity of earth's shaking.
I saw a HDTV show called Supervolcano! a few months ago, where they speculated about the Yellowstone Caldera erupting. It was pretty neat. They talked of Toba being the last supervolcano that has erupted.
I'm aware that some volcanic activity can alter global temperatures. Volcanoes also can produce far more of the greenhouse gasses than we can.
I hope that Earth altering (global temperature) volcanic activity is not imminent. We need to be aware though.
Posted by: Marty Salo | May 14, 2006 at 09:53 AM
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