Hi All. Here is a study done on the Parkfield area. I found it quite interesting. Take Care…Don in creepy town

In the January 27 issue of Science, Robert Nadeau, William Foxall, and McEvilly reported their analysis of phenomena observed between 1987 and 1992. The study is part of Nadeau's dissertation.

They observed that only a small fraction of the fault zone was responding to the motion of the plates; almost two-thirds of the several thousand earthquakes recorded occurred in less than one percent of the active fault zone. The earthquakes were clustered in approximately 300 small cells, each about 20 meters across, unevenly distributed along the fault. When one cell was activated, another would go off as far away as about 200 meters, implying some sort of communication process between the two cells, such as fluid migration in the rocks.

In the course of the study, conducted during what is thought to be the final portion of the interval between the last big earthquake at Parkfield and the one due to come, the frequency of small earthquakes has increased steadily, from fewer than 200 earthquakes per year to 500. At the same time, they are happening deeper in the earth, and fewer of them reside in the cluster cells. According to the scientists, these changes in seismic activity may be signals of an impending magnitude-six quake.

• Parkfield