Lasers help in studying earthquake effects

International geologists studying the aftermath of a Mexican earthquake say a laser tool allows them to see changes in the landscape down to a few inches. Scientists from the United States, Mexico and China said laser measurements are giving them the most comprehensive before-and-after picture yet of an earthquake zone, using data from the magnitude-7.2 event that struck near Mexicali, Mexico, in April 2010. Working with the National Center for Airborne Laser Mapping, researchers flew over the area with LiDAR -- light detection and ranging -- that bounces a stream of laser pulses off the ground and can measure surface features to a few inches. The researchers were able to make a detailed scan over about 140 square miles in less than three days and compare that with a LiDAR scan made in 2006 by the Mexican government. The new LiDAR survey further revealed warping of the ground surface adjacent to faults that previously could not easily be detected, said Michael Oskin, a geologist at the University of California, Davis, and lead author of the paper. "That would be very hard to see in the field," Oskin said in a release from the National Science Foundation, which funded the LiDAR survey. "We can learn so much about how earthquakes work by studying fresh fault ruptures," he said.