The project was funded by the National Science Foundation via the Earthscope program. It started in 2004 with about 450 stations deployed in the western US, rolled from west to east after a 2 year period. All stations transmitted data in real time to the Array National Facility operated by UC San Diego, and after an in-depth data quality check, the data were further moved to the IRIS Data Management Center in Seatlle. Each station uses one broadband seismometer (typically STS-2.5), one Q330 digitizer with one Packet Baler 44 recorder, one Episensor accelerometer, 2 barometers, one infrasound sensor, and one temperature sensor. The last deployment is in Alaska, replacing the STS-2.5 by the STS-5A borehole seismometer, with the goal to finish all installations in 2017.
Currently, the Transportable Array is moving to Alaska with our instruments, where many of the stations are deployed in ultra-harsh and rugged, helicopter only accessible locations.
All stations are equipped with the Q330s including Quanterra environmental subsystem, and 70+% sensors are Streckeisen STS-5A
In continental USA, the USArray with 2,000+ installations, have had data return ~99.5% over 10 years of operation with our instruments.
Provided the USArray with Aspen, an open-architecture system that delivers the greatest network reliability, scalability, security, and lowest total cost-of-ownership.