U.S. National Seismograph Network improves earthquake monitoring



The concept of a United States National Seismograph Network (USNSN) dates back nearly 30 years. The idea was revived several times over the decades but never funded. For example, a national network was proposed and discussed at great length in the so-called “Bolt Report” (U.S. Earthquake Observatories: Recommendations for a New National Network, National Academy Press, Washington, D.C., 1980). From the beginning, a national network was viewed as augmenting and complementing the dense, predominantly short-period vertical coverage of selected areas provided by the Regional Seismograph Networks (RSNs) with a sparse, well-distributed network of three-component, observatory-quality, permanent stations.