The DGS maintains its own network of seismometers to detect local earthquake activity. Following an earthquake swarm in 1972, the DGS established its first seismometer station in Newark. The network now consists of five seismic stations spread across the state: three stations in the Newark-Wilmington area, one at the DEMA office in southern New Castle County, and one at the Sussex County Emergency Operations Center. Signals are recorded on paper and captured digitally using Earthworm, a seismic processing system developed by the USGS. These records are shared nationally through participation in the Advanced National Seismic System Network, the Lamont-Doherty Cooperative Seismographic Network, the Northeast U.S. Seismic Network, and the Southeast U.S. Seismic Network. Small local earthquakes and larger earthquakes from other parts of the country and the world are clearly resolved by the network.