Remarkably enough, no consideration of human caused anything was mentioned, nor should it have been.
Interesting stuff.
After studying geology a bit I’m pretty sure there is a direct relationship between volcanoes and earthquakes.
IN many cases, volcanoes are the result of friction caused when one plate dives underneath another. The friction over long periods results in melted rock, or magma. In an area with a thinner crust, it can form a bubble on the surface, think of a weak spot in a tire forming a bubble. Now and then that weak spot breaks open, you have a volcano, the pressure underneath causing it to spray magma upwards and outwards, similar to what happens if the weak spot in the tire breaks.
Earthquakes are the result of large scale movement in the tectonic plates, which constantly move in various directions very slowly. The edges of those plates where they meet are not straight lines, but jagged edges. The most commonly known problem area in the US is the San Andreas fault in California. In times of little or no earthquake activity, it’s still trying to move, but “hung up” on that jagged edge. An earthquake occurs when it suddenly lets go and moves quite a distance to compensate. In some cases, movement of as much as 6 feet at once has been documented. Normal movement is about 2 inches a year, if I remember correctly.
The Pacific plate, which results in the “ring of fire” is rotating counter clockwise, meaning in a couple of thousand years, L A will be part of Alaska. The ring of fire, is a system of volcanoes caused by the friction of that motion. I need to look into it a bit more, but I think areas of high earthquake activity are also associated.
In Japan, the plate is both rotating, and diving under the plate Japan sits on. 42km is not far at all, geologically, when you consider the size of the plates involved. How wide is the pacific ocean? 42km is nothing...how far is the other side of the bed...compared to the drive to the other side of town?
So the friction involved when one plate dives under another, combined with the sudden jerks caused by irregularities in the surfaces of both, should logically result in both volcanoes and earthquakes. Add in the motion of sloshing, you have a place that is not entirely safe to live...
Also consider, any time we see a quake of higher magnitudes, people feel tremors as far as 100 miles away. That’s a lot further than 42km...
Then we have Yellowstone. That’s the one that worries me. Yellowstone is a Caldera, also known as a super volcano. If it blows, and it’s long overdue, it will probably be a combination of earthquake and volcano and will be a major national disaster, if I remember it right, Yellowstone is estimated to have the capability of covering at least half the US with a layer of ash 6 feet thick. Even if no earthquake is involved, it will have a disastrous affect on millions of square miles of real estate. And recently it’s been discovered that the magma pool below it is much much larger than previously thought...4 times as large I think...
Scary stuff, but also very interesting...if you want to know just what a volcano can do, just look up Pompeii.