The research team scanned the area with LIDAR, or Light Detection and Ranging, which bounces a stream of laser pulses off the ground. New, airborne LIDAR equipment can measure surface features to within a few inches.
The scientists finished a detailed scan over about 140 square miles (360 square km) in less than three days. With this data they were able to discover and map the several faults, including a previously unknown one. Since the Mexican government scanned this area with LIDAR back in 2006, they were also able to compare the old and new data to identify just how the many faults in the area reacted.
"This gives new insight into how faults link together to produce large earthquakes, and how geologic structures incrementally grow these events — for example, folding of rocks and growth of topography and basins around faults," Oskin told OurAmazingPlanet.
The laser scan revealed warping of the ground surface next to the faults that previously could not easily be detected. For example, it revealed folding above the previously unknown Indiviso fault running beneath agricultural fields in the floodplain of the Colorado River. "This would be very hard to see in the field," Oskin said.
Using a virtual-reality facility at the University of California, Davis, the research team handled and viewed data from the survey to see exactly where the ground moved and by how much.
"We can immerse ourselves into the 3D data set, down to the individual point measurements — all 3.6 billion of them for the post-earthquake data set," Oskin said.
The scans revealed how seven of these small faults came together to cause a major earthquake.