Hi Canie,

Thanks for the post. Though I'm very pleased the research was done, it proves one thing; there is no way based upon trenching to determine why one fault segment is more likely to break than another.

However, I have to take exception to Toppozada's assessment of the conditions in the Bay Area. First and foremost, the 30 year figure is not based upon any known facts, it was a figure derived from the length of a person's mortgage. This was to promote the citizenry to prepare for an event which they think might occur in their lifetime or within the length of their mortgage.

The pairs matching events he discusses were a pattern where in the past there would be a quake on the SF side of the Bay and a reverberting quake would occur on the East Bay side, usually occurring within 11 years of the preceding quake. After Loma Prieta the USGS told us they expected a twin quake within the Bay Area within five years. However, we must understand Loma Prieta is not part of the immediately SF Bay Area and does not fall within the prior "tennis of earthquakes" events.

We have indeed been absent of moderate earthquake activity since Loma Prieta. As I recall we've had some 5.0+'s near Gilroy, Bolinas and Yountville. However, the pattern of the twin quake events has not occurred since Loma Prieta.

But there are some very good indicators we are on the verge of a major quake within the Bay Area and a lot closer than 30 years. The first being near Pacifica, with a resulting mirror quake in the Alameda area and the Rodgers Creek Fault from the base near Black Point to Ukiah. As to whether we will receive some good foreshocks before the 7.0+ quake arrives, unfortunately, we have no way of knowing.

But in totality, we must understand first and foremost, these reports are telling us to get ready from one end of the state to other. That's the best we can gleam from the information provided.

Petra