Could the IMS Infrasound Stations Support a Global Network of Small Aperture Seismic Arrays?

Abstract

The monitoring of earthquakes and underground explosions worldwide is performed using networks of seismic stations. The vast majority of these stations consist of three mutually orthogonal sensors, one vertical and two horizontal, at a single site. Seismic signals are detected on individual stations, and events are then defined and located by associating the signals recorded on many different stations. Some networks are global (e.g., Romanowicz and Giardini, 2001; Ammon et al. , 2010), and there are increasingly many national and regional networks that, with increasing available computational power and decreasing data transmission and storage costs, are continually becoming denser. This is particularly the case for highly populated regions with significant and destructive seismicity, such as Japan (e.g., Okada et al. , 2004). Networks such as the USArray (Levander et al. , 1999) and GLISN (Clinton et al. , 2014) can comprise both permanent and temporary stations, covering vast regions (usually over a limited time span) to glean information about structure and geophysical processes. It is, however, still the case that large regions of Earth have very poor coverage of permanent seismic stations. Seismic arrays are a special class of seismic station consisting of seismometers at numerous closely spaced sites (usually within an aperture of a few kilometers) such that signal detection and parameter estimation are greatly enhanced by coherently processing the waveforms at the different sites. Progress in seismic array technology was driven largely by the need to monitor underground nuclear weapons testing (e.g., Douglas, 2002), because the events being monitored by any one country were taking place in the territory of another country and it became imperative to be able to detect and correctly identify a weak seismic signal generated by a remote explosion. With the opening for signing of the Comprehensive Nuclear‐Test‐Ban Treaty (CTBT) in 1996 (Dahlman et al. , 2009, …