Hi Jim. This isn’t the first time California was factored in as a possible cause. When it comes to earthquakes I have learned that there is going to be a lot of speculation on the cause. I have also learned never to rule anything out, nor take it as gospel. I look at it as one more piece of a puzzle and look for a place it might fit.

On April 28, 1999 there was a magnitude 3.8 quake in Christmas Valley, Oregon. It was the largest of a cluster of small earthquakes that has been rattling the area since April 11, with 15 measuring more than magnitude 2.0.

Faults are common in this region of Oregon because it sits in the far northwest corner of the nation's Basin and Range province, where the crust is pulled apart in an east-west direction.

Ray J. Weldon, an associate professor of geological sciences at the University of Oregon has conducted research of the area.

Weldon said that a belt of faults known as the Eastern California Shear Zone might also be linked to the crustal activity in Central Oregon.

"If you look at the faults in Central Oregon, they typically run in a northwest-southeast direction," he said. "That's because all of these places are more or less on the boundary between the Pacific and North American plates, and the motion between these two plates is northwest-southeast oriented, so that causes the faults to line up in that orientation." Take Care…Don in creepy town

• Christmas Valley Quakes