"Near" Realtime Seismology

Abstract

How often have we heard the term “realtime” applied to some sort of seismic analysis or process? “Realtime epicenter determination,” “realtime moment tensor solution,” and “realtime earthquake notification” are terms being routinely used to describe current seismic processing. Of course, this is usually a misapplication of the term “realtime.” According to Webster, realtime means “the actual time during which something takes place” and according to the Oxford English Dictionary, it means “the actual time during which a process or event occurs, especially, one analyzed by a computer.” In the strictest sense, for earthquake locations and mechanisms “realtime” would mean during the actual faulting process. A more liberal interpretation might be analysis during the arrival of seismic waves. Currently seismologists seem to use the term “realtime” to mean “automatic” or “pretty soon after.” A 1991 report of the National Research Council entitled “Realtime Earthquake Monitoring” included discussions of early warning and...