Applications of airborne and terrestrial laser scanning to paleoseismology

Paleoseismic investigations aim to document past earthquake characteristics such as rupture location, frequency, distribution of slip, and ground shaking intensity-critical parameters for improved understanding of earthquake processes and refined earthquake forecasts. These investigations increasingly rely on high-resolution (<1 m) digital elevation models (DEMs) to measure earthquake-related ground deformation and perform process-oriented analyses. Three case studies demonstrate airborne and terrestrial laser scanning (ALS and TLS) for paleoseismic research. Case 1 illustrates rapid production of accurate, high-resolution, and georeferenced three-dimensional (3D) orthophotographs of stratigraphic and fault relationships in trench exposures. TLS scans reduced the preparation time of the trench and provided 3D visualization and reconstruction of strata, contacts, and permanent digital archival of the trench. Case 2 illustrates quantification of fault scarp degradation rates using repeat topographic surveys. The topographic surveys of the scarps formed in the 1992 Landers (California) earthquake documented the centimeter-scale erosional landforms developed by repeated winter storm-driven erosion, particularly in narrow channels crossing the surface rupture. Vertical and headward incision rates of channels were as much as ~6.25 cm/yr and ~62.5 cm/yr, respectively. Case 3 illustrates characterization of the 3D shape and geomorphic setting of precariously balanced.