St Helens? lava baffles scientists
Roughly every three seconds, the equivalent of a large dump truck load of lava 10 cubic yards oozes into the crater of Mount St Helens, and with the molten rock comes a steady drumfire of small earthquakes.india Updated: Jan 02, 2006 12:12 IST
Roughly every three seconds, the equivalent of a large dump truck load of lava 10 cubic yards oozes into the crater of Mount St Helens, and with the molten rock comes a steady drumfire of small earthquakes.
The unremitting pace, going on for 15 months now, is uncommon, said US Geological Survey geologist Dave Sherrod. Experts say it is unclear what the activity signifies or how much longer it will continue.
“One view of this eruption is that we’re at the end of the eruption that began in 1980,” Sherrod said. He describes the movement of lava up through the volcano as being “like a sticky piston trying to rise in a rusty cylinder.
These quakes are very small we think they’re associated with that sticking and slipping as the ground is deformed and relaxes.” The dome collapses and grows and collapses and grows, he said.
“It changes its locationit can’t seem to maintain its height at much more than it is now “ - about 1,300 feet. “Then it kind of shoves the sandpile aside and starts over.” It is not entirely clear where the lava is coming from.
First Published: Jan 02, 2006 12:12 IST