Friday, July 11, 2014
Bad News from Mt Saint Helen's
Bad News from Mt Saint Helen's Discovery of What Maybe an Unusually Large Deep Subterranean Magma Chamber Could Make Mt Saint Helen's the Next Crater Lake( Mt Mazama) Lex Loeb Contributor Network . About 7000 years ago Mt Mazama which is sometimes estimated to have been a shield volcano over 12,000 ft tall had a spectacular eruption or series of eruptions that reduced the mountain to a fraction of it's original height to a bit more than 8000 feet in elevation. The mountain was left with a gaping crater like hole in the center of it 4000 ft deep that is partly filled with water and hence now called Crater Lake is among the deepest lakes on earth. Mt Mazama was built up over as much as half a million years and may have lost as much as half of its mass in a mater of hours or day in one or more major eruptions. Various theories emerged as to how Crater Lake was formed. One theory has emerged as most likely correct because of lack of geological evidence that the mountain sides were blown away the why the previous eruptions of Mt Saint Helen's left debris fields, Mt Mazama did not but it left something more ominous-- an enormous area of much of the Western United States covered not just in ash fall but in pumice rock. The theory holds that Mount Mazama was something like a giant pumice rock incubator originating in a giant underground magma chamber. There is an underground chemical reaction that infuses various gases with magma or liquid rock that is thought to be responsible for the formation of ash, pyroclastic eruption flows and Varioius types of rock like pumice. Pumice is infused with enough air or other gases that it is the rock that is light enough to float on water being sort of the equivalent of a rock closed cell foam. Mt Mazama may have been much like Mt Saint Helen's today with less destructive eruptions or minor activities compared to what could be coming later. The evidence of a larger magma chamber field under Mt Saint Helen's and it's having been identified as a possible super volcano that makes the theory of how Crater Lake got the way it is today seem as if Mt Saint Helen's may not yet be done with it's future eruption plans. It could be like a giant pop corn popper about to blow as the magma infuses with gases and becomes explosive. It could be that the recent eruptions going back to 1981 might just be clearing the throat of the volcano for an even more spectacular event. The physics of a pyroclastic eruption with Mt Mazama in mind tells of an eruption of major proportions and as much as 60 cubic miles of material being ejected from the mountain much of it in the form of pumice and ash. Most of the calculated mass ejected has been estimated from between 15 and 60 cubic miles of material and much of it from deep under ground originating in the magma chamber. The ejected mass includes some of the original mountain top that was left missing with the 4000 foot deep crater. The mountain top is mostly theorized to have collapsed within itself filling the evacuated magma chamber below the mountain and might have plugged it to stop a continuation of the eruptions. Mt Mazama continued to vent after the caldera was filled in with the collapsed mountain peak with the formation of the smaller volcanic rise-- Wizard Island that grows as an island in the caldera lake. Mt Saint Helen's may be incubating it's own major eruption deep underground while we sleep. If so it could blanket millions of square miles with volcanic rock and debris. The caldera of collapsed volcano's is not actually a rare phenomenon. There are many examples of volcano's that have calderas formed similar to crater lake. At the moment Mt Saint Helen's has what might seem to be a half finished crater. When Mt Mazama blew the contents of the magma fizz under the earth out as a major pyroclastic flow eruption or eruptions it came crashing down with in the magma chamber. There are different ways to calculate the discharge in volume of cubic miles lost based on how deep the crater is after the collapse but there is a secondary variable that compounds the problem. Fizzy ready to blow chemical reaction magma might far exceed the dimensions of the crater in a deeper magma chamber and rising magma might replace the fizz magma expelled in the eruption thus not allowing the crater floor to fall as far down as it outer wise would have. This could be instantaneous or over time such as we now see Mt Mazama regrowing its volcanic slump pile with wizard island growing out of the lake . The mountain could have blown away part of it's mountain peak and a vast part of the underground magma chamber only to refill instantaneously during or just after the eruption. Mt Saint Helen's has what might be an even larger fizz chamber ready to blow forming below it. The tall snow capped mountain peak just being a gravity plug helping to keep the magma from rising and containing the fizz magma for an even more violent eruption. The theory is that plate tech tonics is responsible for the creation of the volcano of the cascades and that about 50 miles off the Oregon and Washington Shores a the ocean bottom is submerging bellow the continental plate. The ocean bottom plate caries with it all sort of sediments including what can be natural gas, oil, trapped gases and plenty of organic material that settled in layers on the bottom. All of this melts in contact with the molten rock as the ocean bottom plate is submerged miles and miles below the surface of the earth. The organics and gases can contribute to the explosive eruptions in addition to to other chemical reactions in the rocks themselves. Something like a deep underground pot full of chemical reactions with explosive potential form usually just around the point it reaches the distance from the coast of the high cascades. When this mixture blows it can form the volcano like Mt Saint Helen's or completely destroy them. The volcano's are just big massive slump piles of the material that has to be vented from the deep underground explosive cooking pots in the magma. It has to go somewhere and the heaviest stuff will stay closest to the vent. Unfortunately this heavy material chokes the vent and can cause an even more explosive future eruption because even though it is a heavy slump pile mass or a solid core plug , the general area of the volcanic vent that comes to the surface is still the point of least resistance. That is the reason Mt Saint Helen's may still be extremely violent and dangerous. In the 1981 eruptions it blew away a lot of the cover shield and some of the plug but not all of it. Since then the activity at mt saint Helen's has seen a giant core of magma solidify in the vent as a rising lava dome in the crater. This is potentially even More dangerous because it is like a cork being placed in a champaign bottle while someone is still shaking the bottle. Blocking the main vent might mean the mountain will have to find a new point of least resistance to vent the material energy building up deep underground in its explosive cooking pot. The solid lava dome and core could cause a new vent to open or could itself become a flying cork. If enough explosive energy builds up under Mt Saint Helen's something has to give. It could collapse with in itself just the same way Crater lake's mt Mazama did. The discharge could be everything in the cooking pot below blowing out around the lava dome core to the rims of the big slump pile with the pryroclastic material flying out over much of the western United States and the heavier volcanic material including the core falling down into the suddenly empty vent washed clean by the eruption. That danger scenario seems to increase once the size of the cooking pot deep down below in the magma is identified as a much larger area than previously though encompassing much more area around the volcano. Huge volume of potentially explosive material below the volcano (the lid) with a small vent could be the recipe for a big disaster. Mt Mazama expelled over 40 cubic miles of ash , pumice and bits and pieces of the Mt Mazama that covered much of the western United states. Much of Oregon, Washington, Idaho, Montana, Utah. Fortunately these major eruptions only happen once every X number of thousand or hundreds of thousands of years so there is less to worry about except for the great number of other volcano's in other locations each on a different time schedule. So while Mt Saint Helen's maybe stable for a long time to come some other somewhere on earth is likely to be at it's 1000th or 100,000 year and ready to go again. Activity at any volcano does not necessarily mean it will end as a particularly violent eruption but it does give warning to be worried that the potential does exist. It does seem that volcano's will will give advanced warning in the form of clustered earth quakes that something may happen and these should be the advisory to keep one's distance. Because the subduction zone in the pacific off the west coast is one single element to some effect it means that the volcanos in the cascades are related by the same forces. The magma pool discovered under Mt. Saint Helen's could be immidately related to the it's sister mountains, Mt Hood, Mt Adams, Raineer and Jefferson. Saint Helen's Might be discharging pressure for the other or the others may have their own sparate magma pools that because of the continental drift will cause them to errupt at aproximately the same time as the fiz build up in the magma is on the same time scale? For some reason Mt Saint Helen's has been the most active in historical times so it could be taking pressure off for the others? There is enough energy below Mount Saint Helens going a far distance from the center of it's slump pile that much of the electric power in the Northwest could be generated from it thanks in part to the almost infinite year long snow cover that melts and comes down as water. That could be converted to steam, distilled back into water slowly to fill the rivers after being heated . The government would be wise to lease areas outside the center and allow drilling to find out if water can be heated on a constant basis to boiling. I would envision underground boring tunnels that look like subways to probe and eventually industrialize what is likely to blow up and become a mess anyway sooner or later. .