Updated Salsa3d Tomographic Velocity Models for Improved Travel-Time Prediction and Uncertainty
Description:
Monitoring the Earth for nuclear explosions depends on seismic data to detect, locate and characterize suspected nuclear tests. Motivated by the need to locate suspected explosions as accurately and precisely as possible, our team at Sandia National Laboratories and Los Alamos National Laboratory developed a specialized tomographic model of the compressional wave slowness in the Earth’s mantle, SALSA3D (SAndia and LoS Alamos 3D; Ballard et al., 2016). While the aim of conventional tomographic modeling is to better understand the structure and dynamic history of the Earth’s mantle, the primary focus of SALSA3D is on the accuracy and precision of travel time predictions for P and Pn ray paths through the model with quantifiable uncertainty. We obtain path-dependent uncertainty estimates for travel-time predictions by computing the full 3D model covariance matrix and then integrating slowness variance and covariance along ray paths from source to receiver. While this uncertainty method requires significant additional computational resources to develop and store when compared to simple distance dependent uncertainty estimates, the result is a more complete prediction capability that can be incorporated into event location estimates using this model. In this contribution, we present updated SALSA3D P and S-wave slowness models. The updated models utilize an extensive dataset with stronger quality control measures, which allows for improved resolution compared to previous iterations of SALSA3D. We observe a significant decrease in the root-mean-square (RMS) residual of the predicted travel times, indicating the new models produce improved travel-time estimates that will result in better location estimates and robustly characterized uncertainties.
Session: Earth’s Structure From the Crust to the Core [Poster]
Type: Poster
Date: 4/18/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Andrea C. Conley
Student Presenter: No
Invited Presentation:
Authors
Andrea Conley Presenting Author Corresponding Author acconle@sandia.gov Sandia National Laboratories |
Robert Porritt rwporri@sandia.gov Sandia National Laboratories |
Kathy Davenport kdavenp@sandia.gov Sandia National Laboratories |
Michael Begnaud mbegnaud@lanl.gov Los Alamos National Laboratory |
Charlotte Rowe char@lanl.gov Los Alamos National Laboratory |
Anant Hariharan anharih@sandia.gov Sandia National Laboratories |
Clara Stanbury cstanbur@lanl.gov Los Alamos National Laboratory |
Sanford Ballard sballar@sandia.gov Sandia National Laboratories |
Julia Sakamoto jsakamo@sandia.gov Sandia National Laboratories |
Updated Salsa3d Tomographic Velocity Models for Improved Travel-Time Prediction and Uncertainty
Category
Earth’s Structure From the Crust to the Core