Forty-three volunteer seismological teams participated in monitoring the 3-kiloton nuclear detonation of Dec. 10, 1961. Nearly all the teams were within a radius of 600 mi of GNOME ground zero, located approximately 25 mi SE. of Carlsbad, New Mexico, and most were in or near the Delaware Basin. Standardized methods of calibrating the seismic equipment and synchronizing time references were required to obtain accurate data on the amplitudes and travel times of seismic waves. Calibration of seismograph systems was done by a weight-drop method. A voice count before and after the shot, as well as audible pulses each second, were transmitted over a special broadcast network to synchronize the timing. Gain settings were based on data from a previous nuclear detonation of comparable size. Seismic wave travel times for the central U. S. were used to estimate times of first arrival at each team. As evidenced by the quality of records and considering the limited data available upon which to base operational procedures, the volunteer-team monitoring of the GNOME event was a successful effort.