I tend to favor Lowell's theory that there's a relationship between the solar flares and earthquakes. Granted, we don't fully understand the relationship, but I have to believe that the billions of tons of solar matter hurled towards our planet has some sort of impact.

Here's what we know for a fact about solar flares:
Space probes have shown that some of earths atmosphere is lost to space when our magnetosphere is compressed during these events.
They often disrupt radio and satellite communication by bombarding our ionosphere with electro-magnetic particles.
Airplane pasengers can get a dose of radiation equivalent to a medical X-ray from the radiation.
They trigger Geo-Magnetic storms, which cause surges in power grids.
The aurora borealis (northern lights)glow brightly as the elements in earths atmospere near the poles are ionized.
Earth's upper atmosphere is heated up as ultraviolet light and x-rays hit it.

We're learning more every day about this massive star we orbit, without which our earth would be a cold, dark rock.

All the best, Billion