19–23 Jun 2023
Hofburg Palace & Online
Europe/Vienna timezone

Using a Consistent Travel-Time Framework to Compare Three-Dimensional Seismic Velocity Models for Location Accuracy

20 Jun 2023, 11:00


Board: 2
E-poster T1.2 The Solid Earth and its Structure Lightning talks: P1.2-2


Mr Michael L. Begnaud (Los Alamos National Laboratory (LANL))


Location algorithms have relied on one-dimensional (1-D) velocity models for fast, seismic event locations. The fast computational speed of these models made them the preferred type of velocity model for operational needs. Three-dimensional (3-D) seismic velocity models are becoming readily available and usually provide more accurate event locations over 1-D models. The computational requirements of 3-D models tend to make their operational use prohibitive. Comparing location accuracy for 3-D seismic velocity models tends to be problematic as each model is determined using different ray-tracing algorithms. Attempting to use a different algorithm than used to develop a model usually results in poor travel-time prediction. We have previously demonstrated and validated the ability to quickly create 3-D travel-time correction surfaces using an open-source framework (PCalc+GeoTess, www.sandia.gov/salsa3d, www.sandia.gov/geotess) that stores spatially-varying data, including 3-D travel-time data. This framework overcomes the ray-tracing algorithm hurdle because the lookup tables can be generated using the preferred ray-tracing algorithm. We have created first-P 3-D travel-time correction surfaces for several publicly available 3-D models (e.g., RSTT, SALSA3D, G3D, DETOX-P2, etc.). We demonstrate using these correction surfaces to compare models fairly and consistently for seismic location accuracy via a set of validation events and International Monitoring System stations.

Promotional text

Allowing for direct comparison and/or use of 3-D velocity models pertains to Goal 1 for identifying opportunities/methods for improving nuclear test monitoring. Goal 4 is also relevant for supporting civil and scientific applications, as well as capacity building.

E-mail [email protected]
Oral preference format in-person

Primary author

Mr Michael L. Begnaud (Los Alamos National Laboratory (LANL))


Ms Kathy Davenport (Sandia National Laboratories (SNL)) Ms Andrea Conley (Sandia National Laboratories (SNL)) Mr Robert Porritt (Sandia National Laboratories (SNL)) Ms Christine Gammans (Los Alamos National Laboratory (LANL)) Mr Sanford Ballard (U.S. Department of Energy, National Nuclear Security Administration)

Presentation materials