Many buildings in the Los Angeles and other surrounding areas may be in worse shape for surviving the “big one” than many engineers and scientists used to think. On the basis of surveys of several dozen buildings in the region in the aftermath of the Landers and Northridge earthquakes, scientists now warn that buildings—especially tall ones—may not fare as well as expected because current construction practices do not fully reflect a solid understanding of ground shaking—that is, how far, how fast, how intensely, how long, and in what direction the ground moves. As a result, established building codes may be inadequate, according to U.S. Geological Survey seismologist Thomas Heaton, who presented his findings at AGU's fall meeting in San Francisco in December.