TERRESTRIAL LIDAR SCANS OF THE EL MAYOR-CUCAPAH EARTHQUAKE SURFACE RUPTURE

We collected ground-based lidar scans with centimeter resolution of surface rupture associated with the 4 April El Mayor-Cucapah earthquake. Two teams, using instruments from UC Davis and UNAVCO, commenced data collection twelve days after the earthquake. Four sites were scanned from multiple positions, covering approximately one kilometer of fault length. These scans preserve fine-scale fault-zone features including scarp free-faces, fault striae, landform offsets, distributed faulting and warping of the ground surface. The surveys focus on the zone of maximum slip identified along the Borrego fault, and document a range of fault localization in various substrates. These surveys represent among the first uses of lidar for rapid scientific response following an earthquake. This dataset also serves as an archive of fault slip and will form the basis for repeat surveys to record fault scarp degradation and postseismic deformation. Here we present examples of various rupture styles captured by the lidar scans. We also compare preliminary slip measurements extracted directly from the full-resolution lidar point cloud to independently collected field measurements.