Dictionary:Large aperature seismic array (LASA)
A particular geophone array (in Montana) used to detect nuclear explosions and distinguish them from earthquakes. LASA consisted of 21 subarrays of 25 detectors each, the subarrays being about 7 km in diameter and the LASA itself about 200 km in diameter. Other large-aperature arrays include NORSAR in Southern Norway and UKAEA (United Kingdom Atomic Energy Authority) in Southern Scotland, Yellowknife in Canada, Australia, and India. Also called phase array stations.