USArray

After covering the lower 48 United States from coast to coast with a grid of nearly 1700 sites, the last seismic station of the EarthScope Transportable Array has finally been installed in Alaska. IRIS has commemorated the event with a post titled "EarthScope’s Transportable Array Spans Alaska, the Last Frontier." The IRIS article includes a detailed map of the Alaska TA stations, highlighting the location of the final station A19K. 

The alligator photographed guards SESAME's station E22.  Locals report the alligator likely made a short traverse through the forest from a nearby river, where alligators are commonly spotted, to call the pond home.

The Transportable Array (TA) is a gridwork of broadband seismic instruments that are being installed across the continental United States (see a map of TA stations that have been installed to date).  They are laid out in a rectangular array with approximately 75 kilometer spacing between stations stretching from Canada to Mexico and from the Pacific Ocean eastward.

The Flexible Array is a pool of portable seismic instruments supported by the Array Operations Facility at the PASSCAL Instrument Center. The instruments are available for PI-driven research projects associated with the goals of Earthscope. The pool consists of broadband (325), short-period (100), accelerometer (20), and controlled source (1700) stations.