The LB3D and ELB surveys were conducted by NodelSeismic on behalf of Signal Hill Petroleum for the purpose of better delineating the Long Beach oil field. The surveys used the Fairfield Zland system in which each sensor is recorded contiuously with its own autonomous recorder. The batteries in the sensors last 11-14 days, so the sensors are swapped out every 10 days. A crew can typically change 80 sensors/day. The LB3D array was deployed for approximately the first 6 months of 2011, and had approximately 5300 sensors. The ELB was deployed for the first 3 months of 2012, and had approximately 2500 sensors. The receiver density for both is about 75 sensors per square-km. Note that the diagonal stripe of missing sensors in the upper-right of the Long Beach array is the main runway of Long Beach Airport.
