Transportable Array station install in Mineral, Virginia
USArray has a large traveling network of 400 high-quality, portable seismographs that are being placed in temporary sites across the United States in a rolling fashion. Station spacing is ~70 km (42 mi). Transportable Array data are extremely useful for mapping the structure of Earth's uppermost 70 km. The array was initially deployed in the westernmost United States. Unless adopted and made into a permanent installation, after 18-24 months, each instrument is picked up and moved to the next carefully spaced array location to the east. When completed, over 2000 locations will have been occupied during this program.