Dose San Francisco have so many earthquakes as it is so near the San Andreas fault line?

Question

Also the San andreas fault line forms the boundry between which two techtonic plates?

Answer 1

http://geomaps.wr.usgs.gov/sfgeo/geologic/stories/sliced_up.html
Check out the Bay area map at this site. It shows that in this area, the San Andreas fault system is not just the San Andreas fault, but a whole series of faults on which earthquakes occur: San Gregorio, Hayward, Calaveras, Rodgers Creek, Maacama and more!
Here's what USGS says: "Although the San Andreas Fault itself is often thought of as the boundary between the Pacific and North American plates, many faults in the region work together to take up the motion of the plates sliding against each other. Today these faults, which are found from the Pacific Ocean to Mount Diablo, are moving together about an inch and a half a year (about one-billionth of a mile per hour). The movement of all these faults over geologic time has sliced up many rock bodies and moved the pieces far apart. "

Answer 2

The Pacific Plate and the North American Plate. The San Andreas Fault roughly parallels the 280 freeway up the San Francisco Peninsula, crosses the opening of the SF Bay and then goes out the Marin Headlands. The line through Bodega Bay, down through Point Reyes and Stinson Beach defines the fault. The fault goes through Hollister and San Juan Bautista to the south.
Yes, that is why SF has so many quakes.