Hi Petra,

In an earlier post you asked if traffic could affect earthquake frequency, and in the post above you wrote:
> Yes, this study is for LA and SF. <

Can one determine traffic's effect on earthquakes without including sparsely populated areas and islands that have no heavy traffic in the study? Also - San Francisco Bay Area's morning TV traffic reports usually show that Friday morning commute hours have lighter traffic than on Monday through Thursday, so that's something else to consider.

How far below the surface must a seismograph be to detect traffic's rumble?

Mary C.