Semi-Empirical Yield Estimates for the 2006 North Korean Explosion
Abstract
Science Applications International Corporation (SAIC) is testing a semi-empirical signal processing approach to estimate the yield of explosions. Under Air Force Research Laboratory contract FA8718-05-C-0019, SAIC developed a technique to combine the `truth' of empirical observation with the flexibility of synthetics to generate empirical filters that can be applied to the synthetic seismogram. Specifically, our approach is to design filters that transform the synthetic waveforms to match observed referenced waveforms. In the current project, the technique has been modified (and tuned) to provide yield estimates of interesting events. In particular, estimates of the yield of the North Korean Nuclear Test of Oct. 9, 2006, will be presented. The approach used is to compute semi-empirical synthetic waveforms based on a reference event, then use those synthetics to determine the appropriate scaling (yield) of the event of interest. The semi-empirical synthetics are created by computing a fall waveform synthetic to the reference event then determining a filter that transforms the synthetic to the observed data, which is then applied to the new event. The empirical correction should include many of the non-modeled complexities information, particularly if the reference and new events are nearly co-located. As the North Korea event occurred in a seismically isolated region with no nearby earthquakes, more distant events must be used. An active source experiment for wide-angle reflection and refraction near the border in China provides some sort of propagation calibration. While the yield from the China experiment was small (1.2-1.5 tons), a good signal was recorded at the station MDJ for one particular explosion. This event, roughly 1/2 way between the North Korean Nuclear Explosion and MDJ, provides our reference event for our yield estimate of the North Korean Nuclear Explosion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2008
- Accession Number
- ADA487584
Entities
People
- David H. Salzberg
Organizations
- Leidos