The issue is not hillside. In this area there are tons of houses built into the area hills. Some of them are practically standing on stilts. I have never heard of them collapsing during an earthquake and sliding down the hill. Not saying it cannot happen but we have quakes here ALL the time and that does not happen. Collapsing houses have more to do with what they are built on and was the house built to earthquake codes? It is not an issue of flat vs. hillside.
If the house is built on bedrock then you have little to worry about. If it is not, then you are potentially screwed. Houses built in the marina (flat) have totally collapsed during bad earthquakes. Houses in that part of town are built on landfill—not bedrock. Landfill is prone to liquefaction during an earthquake and when that happens your screwed.
BayGBM is correct here.
No homes on any hills slid during the 89 Loma Prieta quake, yet a majority of the Marina district caved in due to the landfill being the base it was built on from 1906 quake in SF.
Berkeley Hills were unharmed. I know that sounds odd to mention Berkeley and SF together for the same quake, but remember the Loma Prieta epicenter was near Santa Cruz much farther than the distance of SF to Berkeley.
I think the better question here would be if you mind walking up hills, driving the (sometimes) winding roads and depending on location, how long you want to drive and get stuck in traffic.
