What was the intensity of the shaking?

Intensity today is measured on the Modified Mercalli Intensity scale. (Thanks to ABAG - Association of Bay Area Governments - for this table.)

Many intensity values of 8 (Moderate Damage) and 9 (Heavy Damage) occurred in a broad band along the rupture and extending as much as 60 miles to the east of the San Andreas fault.

Modified Mercalli Intensity > 7 in CA

This map shows areas of Modified Mercalli Intensity > 7 outlined by the dashed line. (From Toppozada and Parke, 1982.)

Because of the huge losses in San Francisco, we tend to forget the extensive damage done to other cities along the fault, like Santa Rosa.