The European Arctic: A Laboratory for Seismoacoustic Studies

Abstract

The International Monitoring System (IMS) for verifying compliance with the Comprehensive Nuclear‐Test‐Ban Treaty (CTBT) comprises sensors associated with four monitoring technologies: seismic, infrasound, hydroacoustic, and radionuclide. The so‐called waveform technologies (seismic, infrasound, and hydroacoustic) are used to detect and locate events that could constitute treaty violations. All four technologies may be employed to investigate the nature of events, with the network of radionuclide sensors in place to provide evidence of a nuclear explosion. Historical, political, and technical issues surrounding the CTBT are discussed by Dahlman et al. (2009, 2011). The global IMS infrasound network (Fig. 1) is primarily to detect signals generated by atmospheric nuclear tests. Figure 1. Status of the International Monitoring System infrasound network in August 2014. Filled symbols are certified stations sending data to the International Data Center (IDC) in Vienna. White symbols indicate the treaty coordinates of stations planned or under construction. The IMS infrasound network has been deployed over the last two decades (Brachet et al. , 2010; Christie and Campus, 2010), and only with the network approaching completion has a realistic picture of its detection capability emerged (Le Pichon et al. , 2009; Green and Bowers, 2010). The detectability of atmospheric signals is governed by a seasonally varying wind‐determined anisotropy. In the northern summer, the stratospheric winds blow predominantly east to west, facilitating the detection of infrasound at stations west of sources and inhibiting the detection at stations east of sources. In the northern winter, the winds blow in the opposite direction changing the sense of high and low detectability. The reverse patterns occur in the southern hemisphere. There is increasing interest in using infrasound for probing atmospheric structure (e.g., Lalande et al. , 2012), and the broader properties and applications of infrasound are discussed by Evers and Haak (2009) and Hedlin et al. (2012). In October …