Hi All. It seems the Yountville quake may not have occurred on an unknown fault. It seems that someone has know about a possible fault that may have caused the Yountville quake for more then 20 years, but hasn’t been able to get anyone to check on it. The following is in part by CHRIS SMITH Press Democrat Staff Writer on September 6, 2000

Sebastopol geologist Eugene Boudreau has been aware of the location of this fault for sometime now.

"I told the USGS in 1976 about this fault," Boudreau said Tuesday over documents that substantiate that he announced 24 years ago there is a fault running west of Highway 29 and the mapped West Napa Fault.

A leading government geologist working to identify the source of the weekend's Yountville 5.2-magnitude quake said scientists from the U.S. Geological Survey will meet with Boudreau this week and try to determine if his purported fault exists and if it caused the temblor.

"We'll take a closer look at his stuff," said David Schwartz, chief of San Francisco Bay Area Earthquake Hazards Project. Schwartz said he may come to Napa County himself for a look at what Boudreau says are signs that his fault is real.

Though significant earthquakes are rare in the Napa Valley, private geologist Boudreau says he realized he had come across an undiscovered quake source while taking part in a water-well drilling project about four miles northwest of Napa in 1976.

He said he phoned a USGS geologist that year after discovering that there was 60-million-year-old rock a short distance beneath the surface and, nearby, the drilling rig penetrated 800 feet and hit nothing but far younger volcanic and alluvial rock.

Boudreau found the phenomenon existed elsewhere along a path that moves northwest between Napa and St. Helena. He decided the only explanation was that a fault lay between the two fields of very different rock, and that on one side of the divide old rock had slipped down to perhaps 1,000 feet beneath the surface.

Boudreau said a USGS geologist named Kenneth Fox Jr. came to Napa Valley and, after a study, agreed that he had found a fault.

Despite the mention of the apparent fault in Fox's report, it was never added to the Geological Survey's fault maps. When the earthquake hit at 1:37 a.m. Sunday, the agency announced that the responsible fault had never been mapped.

The calculated epicenter, about three miles west-southwest of Yountville, is in the area of Boudreau's fault. He said he toured the area of the possible fault on Monday and found new cracks in roads, evidence that the earthquake occurred on his fault. (This is the road Petra and I were on, but never made it to the area of the cracks.)

I attempted to contact Chris Smith of the Press Democrat to see if he may have any up dates. I learned he is on vacation until the 26th.

Close examination of the Geologic Map of the Santa Rosa Quadrangle, 1:250,000, circa 1982, shows a small northeast trending unnamed fault in the hills southwest of Yountville. (That fault is also shown on the map I have from the Division of Mines and Geology) Its orientation is about N40°E and its southerly projection extends right to the M5.2 epicentral area. Interestingly, the fault seems to bend both Dry Creek and Pickle Creek Canyons in a westward or left-lateral direction as one moves up canyon. The next canyon to the west is Redwood Creek canyon and it too has a conspicuous westward bend at the southwest projection of the unnamed fault, but it is more defuses - perhaps because this is where the unnamed fault would intersect with the Carneros fault system. Its orientation and geomorphology and the directivity damage evidence, however, is highly suggestive as it to be the likely candidate for the Napa M5.2 earthquake. Take Care…Don in creepy town