Real-time GPS Networks on Active Convergent Margins, Updates From Cascadia and Elsewhere

The EarthScope Plate Boundary Observatory (PBO), through a NSF-ARRA supplement, has enhanced geophysical infrastructure in in the Pacific Northwest by upgrading 232 Cascadia GPS stations to high-rate (1 Hz), low-latency (<1 s) data streams (Real Time-GPS (RT-GPS). These upgraded sites are in addition to the original 100 RT-GPS sites, which were part of PBO. By blanketing the Pacific Northwest with real-time GPS coverage, the NSF has created a natural laboratory in an area of great scientific interest and high geophysical hazard in order to spur new volcano and earthquake research opportunities. Streaming high-rate GPS data in real-time will enable researchers to investigate strong ground motion during large geophysical events, which has implications for earthquake hazard mitigation. Because of efficiency in upgrading the original 232 RT-GPS sites, there is funding for an additional 40 sites to be added to the real time caster, including 20, which expand the Cascadia footprint, as well as 20 backbone stations. UNAVCO in collaboration with NOAA will stream RT-GPS and met data from select PBO stations equipped with WXT520 meteorological sensors and high rate data communications. These streams support watershed and flood analyses for regional early-warning systems related to NOAA's work with California Department of Water Resources. NOAA receives a total of 54 streams to support its objectives, including stations in Cascadia. Approximately 20 additional met instruments are currently being added with the expansion of the Cascadia footprint extention. While communications continue to be a major obstacle in streaming high rate data in Alaska, progress has been made. Currently, a cluster of stations on Unimak Island is streaming real-time data through the PBO data acquisition system, and recent upgrades in communications have opened the possibility of streaming additional sites on Augustine volcano. In addition, the expansion of cellular networks in Alaska is opening the possibilities of adding other stations. In summary, UNAVCO, as part of PBO, now operates nearly 350 high-rate real-time GPS (RT-GPS) stations along the western coast of North America and Alaska. The RT-GPS sites within PBO are monitored and managed using Trimble's VRS3Net software. UNAVCO staff is working closely with the UNAVCO community to develop data standards, protocols, and a science plan for the use of real-time GPS data.