Undersea Faults Make Caribbean Quakes Hard to Study

One of the challenges for assessing earthquake hazards in the Caribbean is that most of the tectonic plate is below sea level and “we can only access the active faults where they are exposed on the islands,” she adds. This is in sharp contrast with the San Andreas Fault in California, where monitoring equipment is in place on both sides of the plate boundary along its entire length.

“Accurate assessment of earthquake probability requires a lot of data, which we just don’t have at this time for the Caribbean,” Cooke explains. “Of course the effective mitigation of earthquake hazards doesn’t just depend on assessment of earthquake probability. Good building code and disaster plans are also needed by all communities living in areas of active faulting.”

Cooke and colleagues in her UMass Amherst lab are among only a handful in the world who use a more accurate and sensitive wet clay box rather than sand box for fault modeling. While sand is easier to work with at the outset, it does not “remember” a fault cut as accurately. Clay is more like real Earth in expressing discrete slips along a fault line.

Cooke says anything we can do before an earthquake strikes to better understand how a fault is behaving, how it’s accumulating stress and how it might relieve that stress in a quake will help us understand the physics of the fault better and help prevent losses. She uses both numerical models in the computer and analog models in the clay in order to better understand tectonic systems.