Friday, 25 February 2011
A theme picked up from this post on Erik Klemetti's 'Eruptions' blog.
We keep on hearing in the media that this or that volcano is overdue, and that consequently "We're all doomed!". Yellowstone is 'overdue', Mt Baker, Mt Rainier, and just about every currently quiet volcano on the planet is 'overdue'.
The problem is that we still don't seem to understand more than the basics of what makes a volcano go 'foom!' We understand the what, but as to the underlying when and where, we're pretty much adrift, making half educated guesses. We are told that we're 'overdue' for a 'big one' (Earthquake) in this area, but the problem is that there is too little information available on the stresses building up in the crust below us. Ergo we get caught out when something like the Christchurch disaster hits. Millions, billions even are wasted on 'preventing' phantasms like (I really do get tired of the whole circus) man made global warming when there are far greater local risks from unmapped seismic activity. Then a cynical voice pops into my head saying "Ah, but you can't tax volcanoes and earthquakes, can you?"
A minor breakthrough in predicting volcanic activity has been published over at UBC Vancouver, where certain kinds of eruptions can be predicted by their sound signature. Specifically those with 'stiff' magma. Yet we're no closer to predicting when or if a Volcano will erupt, or a major earthquake will occur. Yes we can monitor swarm activity, but the information we get from that is currently very superficial.
The Earth under our feet talks, it resonates, it shouts. Humankind's problem is that we firstly have a poor understanding of what the earth's crust is trying to tell us, and secondly trying to listen is a little like having an in depth conversation in a Disco. There's a too much background noise, not just from human but from other activity. Isolating and eliminating various sound signatures is stuff that until recently was the purely the domain of military sonar specialists. Yet like trying to chat up an attractive person of gender choice (let's not be sexist here- meh), sound is only part of the communication. Relying on sound alone easily gets you into situations with metaphorical undergarments round knees and real red face. Depending upon the situation and whether you're having fun, or perhaps not.
Carrying on with the chatting up in Disco conceit, there's far more to detecting eruptions than simply sound. There's motion, expression, and perceived mood. Sometimes these moods are hard to divine, but they are there. So maybe sound detection alone is only a part of the answer.
It has been posited that changes in geomagnetism or even changes in the solar magnetosphere may have a subtle impact on volcanism, rather like Svensmark's cloud climate hypothesis; where increased particle bombardment from cosmic rays when the solar wind is low increases cloud formation, increasing albedo and thus reflecting sunlight away from the Earth's surface. Thus making the Earth cooler.
Study of other planets in the solar system tells us that volcanic activity can be driven by energy generated by a body moving through a magnetic field. Published work by Russian researchers Sergey Pulinets and Kirill Boyarchuk, amongst others, point in this direction. As Earth is known to have a nickel iron core, so it is suspected does Io, one of Jupiters Inner moons. Now Io, the moon in question, is a highly volcanically active place, and has a curious phenomenon suspected to be due to magnetic activity, a ‘flux tube’ of highly charged electrical activity connecting Io and Jupiter. It is thought that this produces an inductive heating effect in Io’s nickel iron core, driving the observed high level of volcanic activity. This is perfectly in line with accepted electromagnetic theory where a metallic body moving through a magnetic field will induce electromagnetic activity in said body.
It may interest anyone who gets this far in my often poorly structured posts, that similar 'flux ropes' between the Sun and Earth have been observed by NASA's THEMIS mission.
Ergo, it may be argued that observed changes in the interaction between the Sun and the Earth’s magnetic fields may have some effect upon the heating effect of the Earth’s core, thus providing a driver of volcanic activity. Local changes can be measured with magnetometers. Whilst this type of measurement alone may not be sufficient to act as a volcano / earthquake early warning device, in combination with stress meters, additional observations should be sufficient to build up a better picture of what the Earth is telling us, deep down.
Going back to the chatting up in the disco conceit, thus may we be able to see what the object of our intentions (Seismic activity) is going to do by joining up the dots of sound, electromagnetism and observed local physical changes. Thus easing the task of knowing what 'mood' our potential date is in. Then we may have a better idea of what any given volcano or earthquake fault is liable to do, and perhaps get the hell out of Dodge before a Pompeii happens.