Note the comment on high rise collapse. That was presented at the SCEC annual meeting a couple of years ago. Consider the following though. The bad scenario earthquake is one that starts down by Salton Sea and ruptures to the northwest. That is the one that they would warn about. If it started in Palmdale and ruptured to the SE, the shaking would not be as bad in LA. But, consider the wider San Jacinto system. Historically,it has ruptured in pieces, in M7 quakes. But, could it cascade and make a high end M7 (say, 7.7)?

1992 Landers was this type of cascade. We are interested in this because there are a couple of papers that say faults that have large cumulative (total) displacements, like the central San Andreas with 300+ km of slip, are capable of larger earthquakes because they are "smoother" (one of the papers is by Steve Wesnousky and someone else). I just published on the North Anatolian fault near Istanbul saying that the interpretations that the northern branch, the one closest to Istanbul, only has 4 km of total displacement, are wrong. We (Kurt et al) have a manuscript in preparation that this fault has 8 km of slip in just the last half million years (19 mm/yr), with it likely having been active much longer with tens of km of displacement.

Lots of tall buildings is Istanbul. Most are on far better rock than those in downtown LA, but who knows about design and construction. It likely matters whether there will be a high-end M7 (say, 7.6) filling the 150 km Marmara gap, or a series of M7s over time.

Chris