Hi Todd. Good question. Unfortunately I don’t have an answer. However I don’t think the question as to which fault the Loma Prieta quake occurred on has ever been settled. There are some who say it was the San Andreas, others say it was the San Andreas plus another fault such as the Sargent, or the Vergeles fault. Then there are those who say it occurred on an unknown fault.

The quake was identified as having about 2/3 strike-slip and 1/3 thrust.

There was an M=6.0 quake in the general area on 02/26/1864. It is listed as being in the southern Santa Cruz Mountains but when I put the location in on a map it shows the quake occurring in Paradise Valley in my Aunts front yard. This is about 1 mile west of Morgan Hill.

On 10/08/1865 there was an M=6.5 just north of Santa Cruz. It has been identified as being in the southern Santa Cruz Mountains.

On 04/24/1890 there was an M=6.2 at Pajaro Gap. This is about 7 miles north of San Juan Bautista. It is almost a certainty that this quake occurred on the San Andreas fault.

As you can see the quakes are in the same general area so you can’t rule out the possibility of another quake occurring on the San Andreas, or another fault in the Santa Cruz Mountains area.

As David Schwartz says. I put my money on the Rodgers Creek fault for the area of the next major quake. I could loose my money but that is where I would put it. Take Care…Don in creepy town