OpenTopography, a Science Gateway to High Resolution Topography for Earthquake Research

Date: 4/24/2019

Time: 04:30 PM

Room: Elliott Bay

High-resolution topography is a powerful observational tool for studying the Earth's surface, vegetation, and urban landscape. These sub-meter resolution data, collected with lidar and photogrammetry, have been especially transformative for earthquake research. Thanks to more than fifteen years of investment in lidar data of active fault systems, we now have extensive coverage of the San Andreas plate boundary, faults in the Basin and Range, faults in New Zealand, and multi-temporal coverage for several recent earthquakes (e.g., 2016 Kumamoto and Kaikoura).

OpenTopography is an NSF-funded science gateway that facilitates open access to point cloud and raster topographic data, processing tools to generate and visualize derivative products, high performance computational resources, and education and training. With more than 1.1 trillion points online, OpenTopography is the official host of numerous community lidar datasets collected primarily for earthquake research. These include early examples such as the B4 and EarthScope datasets, as well as more recent data covering the Wasatch fault and the Walker fault system.

With increasing multi-temporal data coverage, especially after earthquakes, we are developing web-based on demand topographic differencing. Differencing of topographic datasets can detect surface change from a variety of tectonic and geomorphic processes including earthquakes, volcanic eruptions, flooding events, and landslides. We are implementing two types of topographic differencing: (1) Vertical differencing is the subtraction of rasters derived from lidar point cloud data. Error estimates of change can be derived from survey accuracies and propagated through the analysis. (2) 3D differencing is performed with a windowed implementation of the Iterative Closest Point algorithm. This calculates the best rigid deformation (translation and rotation) to align windows of point cloud topography and provides a complete 3D displacement.

Presenting Author: Christopher J. Crosby

Authors