Enhancements of Geophysical Models for Monitoring
Abstract
Geophysical models constitute an important component of calibration for nuclear explosion monitoring. In order to keep them relevant to current monitoring problems, we have enhanced the models in several different ways. We will focus on discussing several of the enhancements here. We have significantly improved upon our surface wave model by expanding the region of the existing model of Eurasia and North Africa, south to cover all of Africa and north to cover the polar region into Alaska and Canada. We have also improved on our coverage in existing regions by including station-station dispersion paths based on ambient seismic noise. Surface waves are also being used to derive the crust and upper mantle velocity structure of these regions, including important parameters such as crustal thickness, upper mantle velocity, and lithospheric thickness. We will be comparing some of these results to other estimates of these parameters. We demonstrate some of the latest enhancements that we have made regarding stochastic models. For instance, we have been using the Markov Chain Monte Carlo (MCMC) technique to produce stochastic models in the Yellow Sea - Korean Peninsula (YSKP) region. By including more data sets (Love wave dispersion curves, gravity) and more data from the existing data sets (more travel times, more receiver functions, more Rayleigh wave dispersion curves), we have improved the lateral resolution of the model from 2 degrees to 1 degree. We will discuss some details of the methodology as well as features of the model. Finally, we will focus the last section on research to move beyond past and current 1-D, 2-D, and 2 -D methods and discuss some of the ongoing efforts to transition to fully 3-D models.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA519992
Entities
People
- Kathleen M. Dyer
- Megan P. Flanagan
- Michael Pasyanos
- R. Gök
- Stephen C. Myers
- William R. Walter
Organizations
- Lawrence Livermore National Laboratory