Godpyre: The Cosmology of North African Paleovolcanism (cont.)
By R. Avry Wilson @2005-2006
Planting the seed
What is it about a volcano that would inspire a foundation for certain myths and cosmologies? The answer is simple: whether it be a slow, turtle-like advance of lava flows or an all-out thundering explosion moving millions of tons of rock in seconds, the fear and awe of an eruption can be so great as to be impossible not to be thrust into the mind and memory like the hammer of Thor. Even though modern scientists have a fairly good understanding of what is going on, observing an eruption can be a frightening experience, so in comparison, an individual living 10 or 50 or 100 thousand years ago would have ended up in a psychological frenzy for the rest of their lives. They’d have searched for an answer to what was happening, and the usual response would have been an attribution to some mystical force, thus creating legends and myths. The same can be said of any natural disaster, like floods, tsunamis, earthquakes, tornados and hurricanes. But as destructive as these can be, the true king of local ecosystem obliteration is, was and always will be the volcano. It is also set apart from the others because (ironically) in the wake of an eruption comes new life, as we shall see. The ancients knew nothing of meteorology or geology – they simply saw in their environment the will of the gods being acted out in brutish, devastating reality. From this, myths were born.
Why is a volcano a step above the rest? Just what exactly is a volcano and how does it work?
The first question some might call argumentative once the debate is opened. However, when overall impact, forces and amount of material are considered, nothing can really compare to many kilometers of debris, ash and lava being expelled in a number of hours. Nothing in nature can ensconce such a richness of fury better than a volcano. Recently, in 2005, hurricane Katrina delivered serious damage to the north coastal region of the Gulf of Mexico (especially to the city of New Orleans), and although the destruction will have repercussions for years to come, it cannot and will not affect global climate for years, whereas certain volcanic eruptions can and have done so. Thus, volcanoes have a certain edge on other events in nature, but this is not necessarily limited to global climate changes. This brings us to the second question about just what is it we’re looking at.
A volcano is basically a geologic feature found in conjunction with an opening in the Earth’s crust that allows internal material (be it liquid or gaseous) called magma to be ejected onto the surface. Though mountains are closely associated with volcanoes and are the more common form, such an end-formation is not always the case. For instance, a rarer result is merely a low-lying lava flow and/or ash deposit – like those seen on the Hawaiian and Icelandic islands. Generally speaking, superheated materials in liquid form rise like blobs from the lower part of the mantle (the asthenosphere) up into the lower lithosphere (the ‘harder’ crust that makes up the surface of the Earth) due to the great pressures they are under. These blobs of molten material form into magma chambers which can either ‘carve out’ (by melting) a path to the surface or happen to coalesce at a weak (thinner) point of the lithosphere. If the surface is weak, chances are an eruption is not going to be that big of a deal, however when the strength of the surface is stronger the upward pressures form a bulge in the surface, essentially holding back for as long as it can. Any number of further properties (like rate of rise, size of magma chamber, etc) can determine how big of a bang is imminent. Predicting the exact force of an eruption to any great degree is beyond the means of current geologic knowledge, but general determinations are possible.