Hi Petra. I don’t think the cracks in your driveway, or your patio is being caused by a slow quake.

The portion of concrete at the left hand corner of your garage appears to have been caused by compression. Don’t look at the fault as a line on a piece of paper, but as a living thing that has depth, width and length. The width of that fault could extend 3 to 4 miles to either side of the fault. If that is so then your home as well all others east of where you live are on the fault.

As you know there has not been a major quake on that portion of the fault since about 1600. When there is no apparent lateral movement to that section of the fault the strain has to go somewhere. It spreads out in the form of compression starting at the point where it is locked and moving backwards towards San Pablo Bay while everything south of the point that is locked keeps trying to move northward. Of course there is the reverse. Everything north of the point that is locked is pulling away.

Being as how no movement has been measured at the surface would make me believe that the area that is locked is near the surface. The section of the fault below the locked point can still move. However there is a little problem with that. There are no micro quakes to speak of that indicate movement at any depth.

There is some movement along the fault otherwise there wouldn’t have been any quakes at Santa Rosa, or Rohnert Park.

When the new sites are installed by USGS we may learn more. However a base line must first be established. That could take a year or more. I hope it’s not too little too late. Take Care…Don in creepy town