Hi All. My day started very early this morning for the purpose of exploring some caves in the Clear Creek area, which is south of where I live. The last time I was down there I saw what appeared to be some caves one of which appeared to have had lava near the front of it. The pain in my back and legs dictated that today was not the day to try and climb a cliff to look at an old cave. Anyway there was most likely nothing in the cave except maybe for some bats and it sure didn’t need another bat in it, especially a dingbat.

Not wanting to waste a good morning I woke one of my friends up and asked him if he wanted to go fault hunting with me. He mumbled something then said he would be over. I told him to bring his GPS receiver. He mumbled something else then hung up.

What we found was that the quakes in the area of Gustine were under the extreme northern end of the lake. They are located about a mile south of the bridge that crosses over the northern end of the lake. This is the location of the northern section of the Ortigalita Fault. It runs under the entire lake about ¼ mile west of the face of the dam. There is another section of the fault located further west of the northern section of the fault. It joins the other section of the fault very close to the epicenters of the Gustine quakes.

The Ortigalita Fault is 66K long and has a slip rate of 1mm per year. It is thought to be able to have a quake up to 6.9Ml. It is believed to have had a 6.0M quake in 1866 at 37.00N/121.18W. Take Care…Don in creepy town.