I just spent 10 minutes writing a p[ost and AOL quit and I lost it! Here goes again.

Roger-you did not answer a question I had on your New Guinea-Southern California thread. If you choose to answer it, please start a new thread.

Concerning the map Don posted above: if the ENE-WSW alignments include left-lateral slip, then these left-lateral faults may bound blocks that are rotating clockwise about a vertical axis (looking down). The pattern is similar to that along the San Jacinto fault and in the Salton Sea. Clockwise rotation carries right-lateral plate motion, so the bounding right-lateral fault decreases it slip. Block rotation also can transfer slip between one fault and another (try some cardboard slats with hinges pinned...). Just to make you nervous, in 1987 the ENE Ellmore Ranch M6.2 earthquake was followed a half day later by a M6.6 right-lateral superstition Hill earthquake. But, a swarm that included larger than M4 at Bombay Beach about a year ago (?) was left-lateral, but did not trigger the San Andreas...Chris