Hi Todd. Waves from a quake don’t always work the way you think they should. For instance. My Aunt and Mother lived in mobile homes about 5 miles east of the Loma Prieta quake. I live in a mobile home 27 miles SSE of the Loma Prieta quake. We had more damage in the park I live in then they did. As a matter of fact there was more damage in the Hollister area then in the Morgan Hill, or Gilroy areas that are much closer to the epicenter of the quake.

Why did the Cypress Freeway collapse while others much closer didn’t?

I was in the house Petra lived in while in Petaluma. I can tell I would not to want to be in that house, or any of the others in that area during a major quake. She had cracks all through the house. I helped her repair one at the corner of a window, only to have it reappear a couple of months later. Parts of the patio in the back was lifting in some area and cracking in others. You could see cracks in the curbs along the street with some offset in the curbs. The corner of her garage had a large crack in the drive way and part of it was lifting up as if it was under compression. There are many more indications though out the area she lived in that indicated that there was movement there and that it was ongoing. I don’t know if the movement is being caused by ground water, the Rodgers Creek Fault that is around 3 miles to the east of there, or some unknown fault that is much closer.

With the number of known faults in the Bay Area I suspect there are at least twice that many more that aren’t know. Take Care…Don in creepy town