Simon Winchester is a good author. I have read his books on San Francisco and the Krakatoa eruption. Fine reading. His speculation about the "fourth" corner of the Pacific Rim possibly being ready to go was a bit surprising to me. However, speculation is just that---and who really knows? If it scares people into doing something (and I heard yesterday that one Federal Budget cut was for the Pacific Tsunami Warning Center!!!!), ok. Poor Japan. Actually, I think that the "Butterfly Effect" came from old Asimov stories, where stepping on a butterfly in the past changed world history. Also, I have heard theories (possibly true) that the flopping of butterfly wings in South America could change world climate. OF course, when I drop a glass and break it in my kitchen, it could be the tremor that sets off a big eruption in Mt. Shasta! Who knows...some things are just more probable and provable than others!