Recently, southwestern Pakistan was rocked by a 1-2 punch of major earthquakes. The first one Sept. 24 had a magnitude of 7.7. For comparison, the Loma Prieta Quake which struck the Santa Cruz-San Francisco, Calif., area in 1989 was a 6.9. That was sufficient to collapse parts of Interstate 880, burying motorists beneath concrete. On the Bay Bridge, an entire section disengaged, causing cars to fall into the gap.