Hi Chris. What you say about creep along the San Andreas fault and some of the surrounding is true, but only part of the time.

I live in Hollister and what has been learned about the Calaveras fault in this area could also apply to other faults.

What makes Hollister particularly interesting to geophysicists is that from San Juan Bautista to just North of Parkfield the faults in the San Andreas system are not ``stuck'': instead of moving only during major earthquakes, the usual pattern for faults, they continuously ``creep''. As a result of this creep, Hollister is being ripped in two, for the most part along a remarkably narrow zone running right through the middle of town.

The creep rate apparently varies in an unpredictable way. From Sylvester and Crowell, 1989 (quoted from Rogers and Nason, 1971): ``Movement did not occur between 1910 and 1929, judging from the amount of offset in two sidewalks that were laid in 1910 and 1929, and in a pipeline laid in 1929. Creep commenced sometime after 1929 and averaged 8 mm/yr. Between 1961 and 1967; the slip rate was about 15 mm/yr. Since 1979, two sites have been monitored in Hollister, one showing 6.6 mm/yr and the other, only 2.3 km northwest, creeps 12 mm/yr - the fastest rate of movement measured across any fault in the San Francisco Bay Region.'' (For those not metrically inclined, 12 mm/yr is half an inch a year.

As you can see the creep is not uniform. There are areas within the fault that are moving faster then others.

It might be that the creep of 0.10mm per year along the Zayante-Vergeles is because it’s locked. If that is the case then there is a point in time when it can and will break.

The southern portion of the Rodgers Creek fault in the Bay Area has not shown any movement since about 1600 according to USGS. This fault is the prime candidate for the next major quake in the Bay Area according to USGS.

The Loma Prieta quake of 1989 occurred along a section of the San Andreas fault that had seen very little movement until 16 months and 2 months prior to the quake. In June of 1988 a magnitude 5.1 quake struck 60 miles south of San Francisco. Alerted by the USGS that there was a 1 in 20 chance of a larger earthquake in the next 5 days, the California OES issued an advisory to warn the public. (The usual daily odds of a large quake in the Bay region are 1 in 15,000.) The warning period passed without further activity. In August 1989, another earthquake hit the same area and a similar advisory was issued. Again nothing happened in the specified warning period. However, 69 days later, the area was rocked by the magnitude 7.1 Loma Prieta earthquake, which killed 63 people and caused $6 billion damage in the San Francisco Bay region.

This is facts and what is facts in one location can also be facts at another. You just have to wait for it to become a fact. Take Care…Don in creepy town