I don't have the expertise to contribute...but you may find the following interesting...about 18 years ago I was living in Family student housing at UCSB...on the part of the old complex that was built on fill. There was a M3.0 quake essentially right below (I forget how deep) that was quite the little 1 second jolt...and it put our front door out of line. I M4.0 and we might not have been able to open that door. This was 2 story apartments..
Chris