Here is an excerpt from an interesting npr.org:
Rediscovered Headstones Hold Clues To Calif. Quake
by Cindy Carpien
The Gilliam Cemetery, which lies 60 miles north of San Francisco, appears to be gaining residents lately. But it’s not only because new people have been interred there. Instead, headstones that wound up being buried a century ago have been found and resurrected.
The cemetery’s story begins in 1850, when a wagon train of pioneers left Missouri and settled near what is now Sebastopol, Calif. The Gilliam Cemetery was started in 1852, when Polly Gilliam Sullivan and her husband, Isaac, needed a place to bury their stillborn son.
Many of the town’s pioneers rested peacefully in the cemetery until the morning of April 18, 1906. That’s when the San Andreas Fault ruptured offshore from San Francisco, picking up speed as it traveled north.
An Analysis, 100 Years Later
U.S. Geological Survey seismologist Jack Boatwright first visited the graveyard in 2006, for the earthquake’s centennial. The trip was part of his attempt to create the first digital “ShakeMap” of the quake. He confirmed that some of the strongest shaking happened in this part of Northern California.
Cindy Carpien/NPRAnd the evidence is still visible in old graveyards like Gilliam, where Boatwright found 3-foot marble headstones that had been broken in the 1906 quake — including one for pioneer Elizabeth Crowe, who died in 1889. Her grave marker looks as though it was shattered into five pieces.