The Next ‘Big One’

Is there really a way to predict when the next big earthquake will strike? Tanya Atwater, UCSB professor emeritus and scientist, tackled that question at a UCSB History Associates-sponsored summit this week. The lecture focused on the San Andreas Fault, which formed California’s current landscape and causes the occasional earthquake. The San Andreas is a transform fault, where two tectonic plates slide past each other. This is better than living right on a subduction zone — where two plates collide and one is forced below the other — according to Atwater. The most recent earthquake to hit Santa Barbara was in 1925, recorded to be approximately 6.3 in magnitude. Atwater says seismologists typically consider a “big” earthquake to be one measuring in with a magnitude of more than seven; however, the classification also depends on the location and current landscape of the site.

Atwater’s presentation concentrated on the future of earthquake prediction using animation, maps, and images. Researchers and seismologists currently study seismic activity by studying sediment layers in trench walls, she said. Breaks in layers indicate when earthquakes took place and carbon dating helps determine approximately when they occurred. So when exactly will the next big earthquake hit? “The physics of them make them unpredictable,” says Atwater. “Don’t be afraid of them. They just show you the earth’s alive,” she added. Atwater encourages residents to be prepared for the next potential disaster, since it cannot be predicted. “The longer we wait between earthquakes, the more we’re due for the next.”