CompuServe Messages

Leland, Earthquakes can happen anywhere you have active faults in the bedrock. They aren't limited to plate margins and volcanic regions. No one is quite certain of the origin of intra-plate faults like the New Madrid Fault. One school of thought holds that the New Madrid fault complex is a "fossil rift," what's left of an area where the North American continent almost split apart some 850 million years ago. The rift would have been similar to Africa's Great Rift Valley. It didn't develop into a true rift the way the Mid-Atlantic Ridge did, and it's certainly long dead, but the New Madrid faults may be a remnant of that activity. Jon W.