VISUALIZING DATA FROM EARTHSCOPE’S USARRAY SEISMIC TRANSPORTABLE ARRAY

The EarthScope USArray program generates a large volume of data from across North America. Its Transportable Array (TA) component is currently deployed in a grid of 400+ broadband seismometers with 70 km spacing. The TA has rolled across the contiguous United States and southernmost Canada over a nine-year period and will have occupied ~1700 distinct sites from the Pacific Ocean to the Atlantic Ocean by the end of 2013. All stations continuously transmit multiple channels of 40 samples per second seismic data in near real time, immediately accessible to any user.

The TA provides a unique tool for visualizing large-scale seismic wave phenomena and understanding the relationship of wave propagation to Earth structure. The power of this tool is particularly apparent when displaying simultaneous signals from all stations as a function of time, as well as rendering multiple channels of data from each station. The challenge of conveying 3D motion at each station and the aggregate motion across the entire array necessitates creating movies of these data to illustrate the TA’s time-dependent observations.

Visualizations from TA data include comparison of observed data with 3D synthetics, animations of low magnitude seismicity detected by the migrating TA, and ground motion visualizations that show the excitation of shallow sediments from passing teleseismic surface waves. The movie-based representations of the data also provide a medium for education and outreach, as complex wave phenomena become visible to the untrained eye. We have explored strategies for trying to add a perspective view and a sense of spatial orientation to the visualizations to make them more useful in educational settings for non-specialists. Some of these visualizations are now routinely produced as data products to support research and education.

We will provide examples of the visualization results, including movies of seismic surface waves spreading out on the planet and the use of perspective views, cross-sections, contours, and other graphical techniques as a means to gain insight into the data and the earth structure sampled by the TA.