Systematic calibration of a network of seismographs could meet the seismic monitoring needs of the United Nations' comprehensive nuclear test ban treaty, a feasibility study suggests. To calibrate the network, known as the International Monitoring System (IMS), the three-dimensional seismic structure of the Earth must be taken into account. Deep seismic sounding (DSS) profiles and global three-dimensional seismic velocity inversions play prominent roles.
A verifiable test ban treaty is an important societal and technical goal. An essential ingredient is the ability to accurately locate seismic events, probably within a circle with a radius of 18 km, which is about 1000 km2. This would be for events with magnitude greater than 4 in continental areas.