Final Scientific Report, Integrated Seismic Event Detection and Location by Advanced Array Processing

• Main Authors: Kvaerna, T., Gibbons. S.J., Ringdal, F, Harris, D.B.
• Language: unknown
• Published: 2016
• Subjects: 58 GEOSCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS; COMPUTING; AND INFORMATION SCIENCE; ALGORITHMS; BACKGROUND NOISE; CALIBRATION; DETECTION; MATRICES; MONITORING; NUCLEAR EXPLOSIONS; PROCESSING; SEISMIC EVENTS; SEISMIC SOURCES; Fennoscandia
• Online Access: http://www.osti.gov/servlets/purl/898306; https://www.osti.gov/biblio/898306; https://doi.org/10.2172/898306

In the field of nuclear explosion monitoring, it has become a priority to detect, locate, and identify seismic events down to increasingly small magnitudes. The consideration of smaller seismic events has implications for a reliable monitoring regime. Firstly, the number of events to be considered increases greatly; an exponential increase in naturally occurring seismicity is compounded by large numbers of seismic signals generated by human activity. Secondly, the signals from smaller events become more difficult to detect above the background noise and estimates of parameters required for locating the events may be subject to greater errors. Thirdly, events are likely to be observed by a far smaller number of seismic stations, and the reliability of event detection and location using a very limited set of observations needs to be quantified. For many key seismic stations, detection lists may be dominated by signals from routine industrial explosions which should be ascribed, automatically and with a high level of confidence, to known sources. This means that expensive analyst time is not spent locating routine events from repeating seismic sources and that events from unknown sources, which could be of concern in an explosion monitoring context, are more easily identified and can be examined with due care. We have obtained extensive lists of confirmed seismic events from mining and other artificial sources which have provided an excellent opportunity to assess the quality of existing fully-automatic event bulletins and to guide the development of new techniques for online seismic processing. Comparing the times and locations of confirmed events from sources in Fennoscandia and NW Russia with the corresponding time and location estimates reported in existing automatic bulletins has revealed substantial mislocation errors which preclude a confident association of detected signals with known industrial sources. The causes of the errors are well understood and are primarily the result of spurious identification and ...