Topographic Differencing: OpenTopography and the 2016 M7 Japan Earthquake
High resolution topography is a powerful observational tool for studying the Earth's surface, vegetation, and urban landscape, with broad scientific, engineering, and education-based applications. When areas are imaged two or more times, topographic differencing reveals surface change from tectonic and geomorphic processes including earthquakes, volcanic eruptions, flooding events, and landslides. OpenTopography is an NSF-funded facility that provides open access to point cloud and raster topographic data. I will discuss the on-demand vertical and 3D topographic differencing tools available for overlapping datasets in the OpenTopography archive. The 2016 M7 Kumamoto earthquake ruptured active faults on Kyushu Island, Japan, and produced over 2 m of surface slip. The 3D differencing reveals the fresh surface rupture, on-fault slip, and off-fault deformation. These observations are critical for understanding processes active in the shallow crust during earthquakes.