Hi All. The area around the 3.1Ml quake on 08/05/2002 appears to be sort of a hot bed for small quakes. Using a radius of 5 miles there have been 61 quakes since 1969. For the most part the quakes have been 1 to 4 per year with the exception of 1988 in which there were 8 quakes.

However in 2002 there have been 16 quakes. This increase started on 05/02/2002 with 1 quake. Then in June there were 8 quakes. 4 of those quakes were on June 4, 3 of them on June 5 and 1 on June 7. There was 1 quake in July and there have now been 6 quakes in August that occurred on 08/05/2002.

These quakes could be an indication that a quake in the moderate range could be close to occurring in that area, but somehow I don’t think so. My feeling is that the stress along the San Andreas in the area of Cholame is near maximum and is close to breaking. I just wish I knew how close.

Although more than 145 years have passed since the great Fort Tejon earthquake, there is little reason to anticipate a repeat of that even in the next several decades. Crustal deformation measurements along the San Andreas fault southeast of Parkfield indicate that plate movement is straining the region at a rate corresponding to 3 centimeters per year of right-lateral slip.

This means that movement since 1857 has not been sufficient to repeat the 9 meters of slip that occurred on the Carrizo Plain section in 1857. However, it is uncertain whether the potential for the 3 to 7 meters of slip that apparently occurred along the Cholame section in 1857 has been recovered by crustal straining along the fault since then. Thus it is possible that the anticipated magnitude 6 Parkfield earthquake could trigger, or "grow into," a shock of about magnitude 7 on the Parkfield and Cholame sections.

The Loma Prieta quake in 1989 occurred on a section of the San Andreas that didn’t move as much as the rest of the fault did during the 1906 San Francisco quake. The area of the Loma Prieta quake was in a known seismic gap. The section of the fault in the Cholame area and to a certain extent the area of Parkfield is also in a known seismic gap.

By the way there is another known seismic gap. This is the section of the San Andreas fault between Portola Valley and the San Francisco Peninsula.

As always I reserve the right to be wrong. Take Care…Don in creepy town