EARTHSCOPE’S MULTIDISCIPLINARY USARRAY: STATUS, RESULTS AND PLANS

EarthScope’s USArray program provides unprecedented observation of geologic targets across the continental US through the systematic deployment of seismic, magnetotelluric, and atmospheric instruments. The seismic USArray consists of a Transportable Array (TA), Flexible Array (FA), and Reference Network. The TA has now occupied more than 1500 sites from the Pacific Coast to the Atlantic Ocean. These stations operate for about two years, are deployed in a grid-like arrangement with 70 km separation between stations and include a three-component broadband seismometer and barometric and infrasound sensors. The FA maintains a pool of instruments, ranging from high-frequency geophones to three-component broadband sensors, which are typically deployed in dense arrays to investigate local or regional features over time periods ranging from days to years. Finally, the Reference Network provides a permanent, stationary foundation for the TA and FA, with approximately 100 broadband stations deployed across the contiguous US at roughly 300 km spacing. The magnetotelluric (MT) component of USArray consists of both a fixed backbone of 7 stations and a transportable array of 20+ long-period MT instruments that are deployed campaign-style for up to several weeks on a grid similar to the seismic TA. About 20 instruments are also available for targeted, FA-style studies. About 400 MT sites have been occupied in the NW quadrant of the US and across the Mid-Continent Rift in the Midwest.

We will present the current status of USArray activities and progress to date, with special emphasis on standardized data products that are created from USArray data, including phase picks, seismicity catalog, wave-field animations, observations of the ambient noise field, and MT transfer functions. We will also provide an overview of collaborative experiments and investigations with Canada and potential USArray deployment plans in Alaska, and will discuss opportunities for the seismological education and research communities to participate in and leverage the FA and TA efforts.