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On August 12, 2000 the Russian submarine Kursk sank in the Baltic Sea north of the Kola Peninsula. The sinking of the Kursk was associated with two explosions. Shown here is the filtered, broadband, vertical component seismogram of the Kursk explosions recorded at the IRIS/USGS Global Seismographic Network station Kevo (KEV) in Finland at a distance of about 400 km.
Two events, separated by 135 seconds, are seen in the KEV record. The signal from the first event (ML 2.2) is approximately 250 times smaller than the second event (ML 4.2). However, a waveform correlation detector applied to the data enhanced the signals and allowed the precursor event to be clearly associated with the main event.
First motion and Pn/Sn ratio analysis indicate a complex source mechanism. The most definite seismic evidence that the main Kursk event was dominated by an underwater explosion source is the presence of a "bubble pulse" and water reverberations in the data, noticeable as distinct peaks in the amplitude spectrum of the KEV data. Furthermore, the main event is consistent with an explosion of approximately 5 ton equivalent TNT. The precursor event is associated with a small explosion that presumably disabled the Kursk and caused it to sink to the seafloor where, 2 minutes and 15 seconds later, the main explosion occurred.
For further discussion see:
"Forensic Seismology and the Sinking of the Kursk" by Koper et al., submitted to EOS, October 5, 2000.
Greg van der Vink, IRIS's Director of Planning, will take a 10-month sabbatical from IRIS beginning September 1 to serve as Princeton University's 250th Anniversary Visiting Professor for Distinguished Teaching. Greg will teach in the Department of Geosciences and serve as a Faculty Fellow of the Butler Residential College. Following a national search, van der Vink was selected because of the university's interest in developing new science courses: "In areas such as environmental policy, an increasing number of decisions must be made in the face of ambiguous scientific results, incomplete data, and competing interests. Courses that educate students on the complexities of such decision-making must include not only scientific arguments, but also the economic, social, and political boundary conditions. Dr. van der Vink's background as a geophysicist, combined with his extensive experience in both the legislative and executive branch, make him one of the rare individuals who is well-suited to develop such interdisciplinary curriculum."
IRIS Newsletter |
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Published by
the IRIS Consortium. IRIS Newsletter |
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The Incorporated Research Institutions for Seismology (IRIS) is a university consortium of over 90 research institutions dedicated to monitoring the Earth and exploring its interior through the collection and distribution of geophysical data. IRIS programs contribute to scholarly research, education, earthquake hazard mitigation, and the verification of the Comprehensive Test Ban Treaty. IRIS operates through a Cooperative Agreement with the National Science Foundation under the Division of Earth Science's Instrumentation and Facilities Program. Funding is provided by the National Science Foundation, the Department of Energy, the National Imagery and Mapping Agency, other federal agencies, universities, and private foundations. All IRIS programs are carried out in close coordination with the US Geological Survey and many international partners. The IRIS Newsletter welcomes contributed articles. Please contact the Executive Editor. |
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| Editor-in-Chief: David Simpson (simpson@iris.edu) |
Executive
Editor: Gregory van der Vink (gvdv@iris.edu) |
Production
Editor: Anne DeLaBarre Miller (anne@iris.edu) |
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