Saturday, July 23, 2005

Lavadome growing, crumbling and showing off at night.

Since the 15th of July there have been 7 earthquakes greater than magnitude three recorded at Mount St Helens. The latest was a magnitude 3.2 quake at 02:38 this morning, which was also resulted in a bright outburst from the lavadome in the crater. The heightened level of activity is associated with the crumbling of the lavadome structure, as evidenced in this photo from the USGS.

The USGS/CVO also report that the, volume of the new lava dome was about 54 million cubic meters (70 million cubic yards), or about 60% of the volume of the lava dome that grew in the crater from 1980 to 1986. The rate of addition of lava to the dome from mid-May to mid-June remained at about 1.5 cubic meters (2 cubic yards) per second. The high point of the lava dome (the actively growing spine) on June 15 was 2335 meters (7660 feet), but it is currently lower than that owing to the recent large rockfalls from the spine.


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