Hi Cathryn:

Yep, the Red Line crosses the Santa Monica fault under the Hollywood Hills a little east of todays eq. When they built it, they made the tunnel wider at the point it crosses the fault to allow for creep and earthquakes so that they could realign the tracks without having to modify the tunnel, and if your at the front of the train looking forwards, you can actually see this feature. The Red Line Extension opened about 1.5 to 2 years ago as I recall.

Michael.