The 16 August 1997 Novaya Zemlya Seismic Event as Viewed from GSN Stations KEV and KBS


Summary

Conclusions

1. The 16 August event occurred at least 100 km southeast of the test site, beneath the Kara Sea, and in good agreement with locations estimated by other organizations.

2. At frequencies above 4 Hz, the 16 August event falls within the earthquake population and is separated from the explosion population. Taking the location and discrimination results together, I conclude that the 16 August event was an earthquake.

3. Given that many small events (mb < 4.0) will be examined under the GNEM R&E program, and therefore will be detected only at regional distances, there is clearly a need for continued regionalization effort to prepare for treaty monitoring.

4. The modern arrays, which will be part of the GNEM R&E IMS, played an important role in detection and location of the 16 August, but the long-established stations (such as KEV) are important for event identification and relative location studies. I suggest accepting the 16 August event as an earthquake. It could then be used to help confirm that the other recent small events from north of NZTS (Figure 7) were also earthquakes.

5. Clearly, a chemical explosion at NZTS in the m 3.7 - 4.2 range would be an immense help to the regionalization effort. However, given the weak Sn produced by explosions in this region, and given that Sn attenuation is greater than Pn attenuation, a calibration explosion should not be much less than mb will be fall below noise levels.

Acknowledgements

Thanks to the staff at the IRIS Data Management Center for prompt replies to data requests. The GMT mapping software (Wessel and Smith, 1991) was used to construct figures for this paper. The work is in support of the DOE Comprehensive Test Ban Treaty Research and Development Program, ST482A, and was performed at Los Alamos National Lab under the auspices of the United States Department of Energy, Contract Number W-7405-ENG-36.


Introduction | Background | Location | Discrimination | Summary