Automated Seismic Monitoring System for the European Arctic

Abstract

The paper describes the automated seismic monitoring system for the European Arctic based on an international seismic network located in the region. The core of the system is the NSDL software package developed by the authors for automated detection and location of seismic events. NSDL is designed to automatically monitor the seismic activity of a region using a seismic network, seismic arrays, or individual three-component seismic stations. The described system has two levels. The first level consists of single-station data-processing programs that implement algorithms for detecting and prelocating seismic events based on data from individual three-component seismic stations and arrays. The second level is a program for associating individual station data-processing results, which performs joint location over the network based on events and phases of seismic waves detected at the first processing level. NSDL makes it possible to use a set of 1D layered velocity models for locating remote events the wave propagation paths from which cross regions of the medium with different velocity properties. Decisions about the truth or falsity of the detected candidate events are made with a Bayesian classifier based on the evaluation of a number of amplitude, spectral, and polarization parameters both for single-station and joint (network) processing of seismic events. The use of the seismic monitoring system for the Arctic region showed high reliability of automatically obtained results, significantly sped up the compilation of the final analyst-verified catalogs, and significantly increased the representativeness of the resulting bulletin due to weak events. The level of detail achieved by the described system makes it possible to take a fresh look at the development and structure of the seismic process in the European Arctic and in particular to record seismic events associated not only with tectonic processes but also with cryospheric destruction processes.