LLNL Seismic Locations: Validating Improvement Through Integration of Regionalized Models and Empirical Corrections
The monitoring of nuclear explosions on a global basis requires accurate event locations. As an example, a typical size used for an on-site inspection search area is 1,000 square kilometers or approximately 17 km accuracy, assuming a circular area. This level of accuracy is a significant challenge for small events that are recorded using a sparse regional network. In such cases, the travel time of seismic energy is strongly affected by crustal and upper mantle heterogeneity and large biases can result. This can lead to large systematic errors in location and, more importantly, to invalid error bounds associated with location estimates. Calibration data and methods are being developed and integrated to correct for these biases. Our research over the last few years has shown that one of the most effective approaches to generate path corrections is the hybrid technique that combine both regionalized models with three-dimensional empirical travel-time corrections. We implement a rigorous and comprehensive uncertainty framework for these hybrid approaches. Qualitative and quantitative validations are presented in the form of single component consistency checks, sensitivity analysis, robustness measures, outlier testing along with end-to-end testing of confidence measures. We focus on screening and validating both empirical and model based calibrations as well as the hybrid form that combines these two types of calibration. We demonstrate that the hybrid approach very effectively calibrates both travel-time and slowness attributes for seismic location in the Middle East North Africa, and Western Eurasia (ME/NAAVE). Furthermore, it provides highly reliable uncertainty estimates. Finally, we summarize the NNSA validated data sets that have been provided to contractors in the last year.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15004636
- Report Number(s):
- UCRL-JC-144909; TRN: US200320%%260
- Resource Relation:
- Conference: 23rd DOD/DOE Seismic Research Review, Jackson Hole, WY (US), 10/02/2001--10/05/2001; Other Information: PDF-FILE: 13 ; SIZE: 1 MBYTES; PBD: 27 Jul 2001
- Country of Publication:
- United States
- Language:
- English
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