Robert Mellors

This article describes the rich global digital seismic data set that has been collected from 1975 to the present using a variety of instruments and progressively updated equipment and communication systems. The original IDA very long period (VLP) network operated from 1975 to 1995. The successor IRIS/IDA very broadband network began in 1986 and continues to the present. Collection of these data has supported advances in our understanding of the structure of the Earth’s deep interior and of the long wavelength heterogeneous structure of the mantle; the detailed behavior of large earthquakes; and the discovery of nontraditional seismic sources such as slow earthquakes, glaciers, and landslides. Near-real-time transmission of the data to hazard warning centers has expanded the network’s usefulness as a tool for rapid response to earthquakes, warning to communities affected by tsunamis, and for monitoring compliance with nuclear test ban treaties.