RE: Earthquake

First, Shinya, thanks for the question. It looks like you live in a part of the world where this quesiton has some pertinence. I wish I could answer the question. If I could, I'd be a rich man. I don't think anyone can tell you where the next big quake is going to be.

But, there are some places where large quakes "could" strike, because of the historical record of having large quakes. Certainly Japan would be at the top of the list, as well as Indonesia, the Phillippine Islands, Alaska, and California.

What is important is what is called a seismic gap (here's one for the island of Shumagin in the Aleutians, and one for Loma Prieta in California). Areas that are historically active have earthquakes in patterns. Let's say the average time between major quakes is 125 years, as it is in Southern California. Since it has been almost 140 years since the 1857 quake which would have measured about 8, it is time for another.

This "gap" in the record is what to look for. Of course, if you don't know the recurrence interval, a seismic gap would do you no good. Not only that, but you are not very specific to the actual date or time. The prediction wouldn't do any good if it was too nebulous.

Again, look for seismic gaps in places where quakes happen regularly. There was a M7 quake in 1989 in San Francisco, California, which was "predicted" by some USGS scientists who saw a definite gap in the San Andreas Fault record. There is a video which details this. It is an episode of Nova, a PBS broadcast. Check it out at your local video store.

Thanks again, Shinya, and write back if you have more questions. God bless you and your classmates.

Mike Martin, Porterville High School, Porterville, California
mmartin@porterville.k2.ca.us
http://porterville.k12.ca.us/phs/phssci.html