Hello Mike,

That makes sense. I will assume for now that a magma movement within a volcano would be isotropic, and there would not be a double couple mechanism involved. Even if a large strato blows, the ground will shake, but the mechanism is explosive resulting in a red beach ball, meaning first motions 360 around the thing would all be first up? The other extreme would be a circular sea floor collapse which would produce an implosive force, thus the beach ball would be white. Am I on the right track here? Just asking.

Thanks,
Glen