posted on Feb, 7 2006 @ 05:25 PM
I wouldn't worry about mount st helens to much at the moment. Although it occasionally clears its throat (which is actually good), we are unlikely to
see an eruption on the scale of the 1981 (just yet!). The diffrence between then and now is that the cone of material that built up in 1981 was on the
flanks of the mountain. This made the flank of the mountain very unstable, this combined with the inflating magma chamber cuased the massive
landslide, which then exposed the magma chamber, that itself was under pressure, and in the same way that if you shake up a bottle of coke and then
remove the cap quickly, it will spray coke everywhere, the same thing happened at Mt St. Helends. The landslide exposed the pressurised magma chamber
causing the massive lateral blast.
At the moment the cone building up at Mt St.helens is roughly located centrally within the crater left by the 1981 eruption. Therefore it does not
have the aid of gravity on its side. The magma from Mt. St. Helens is very viscous, because of its high silica content. The upshot of this is that it
tends to get stuck in volcanic vent leading up into the crater. The real danger occurs if the this material blocks up the vent to such a degree that a
large amount of pressure builds up behind, in this cirumstance we may see a sizeable volcanic eruption, but probably not as large as in 81'