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Comparing Three-Dimensional Seismic Velocity Models for Location Accuracy

Description: 

Location algorithms have traditionally relied on one-dimensional (1D) velocity models for fast, seismic event locations. 3D seismic velocity models are becoming readily available and usually provide more accurate event locations over 1D models. We have previously demonstrated and validated the ability to quickly create 3D travel-time lookup surfaces (3DTTLS) for seismic event location algorithms using an open-source framework (PCalc+GeoTess, www.sandia.gov/salsa3d, www.sandia.gov/geotess) that easily stores spatially varying data, including 3D travel-time corrections to a standard 1D velocity model. This framework allows for fair and consistent comparisons of 3D velocity models because the lookup tables can be generated using the exact ray-tracing algorithm that is preferred for a given 3D model. We have created first-P and first-S 3DTTLS for several publicly available 3D models (e.g., RSTT, SALSA3D, G3D, DETOX-P2, etc.). Using several global-scale seismic events, we compare epicenter location accuracy (LocOO3D, www.sandia.gov/salsa3d) using 3DTTLS for these 3D models to demonstrate how velocity models can be fairly compared for special events. In addition to standard epicenter comparisons, we will investigate combining epicenter determinations into an ensemble location for each analyzed event.

Session: Network Seismology: Recent Developments, Challenges and Lessons Learned - V

Type: Oral

Date: 5/2/2024

Presentation Time: 02:30 PM (local time)

Presenting Author: Michael

Student Presenter: No

Invited Presentation: 

Authors