Updates to the Regional Seismic Travel Time (RSTT) Tomography Model

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

The Regional Seismic Travel Time (RSTT) tomography model has been developed to improve travel time predictions for regional phases (Pn, Sn, Pg, Lg) in order to increase seismic location accuracy, especially for explosion monitoring. The RSTT model is specifically designed to exploit regional phases for location, especially when combined with teleseismic arrivals. The latest RSTT model (version 201404um) is located on the Sandia National Laboratories web site (http://www.sandia.gov/rstt). We are in the process of updating the RSTT model to include new features. The original model used CRUST2.0 combined with an a priori model in Eurasia from US National Laboratories. The newest crustal update will use the CRUST1.0 version that includes more detailed and realistic structures. New event data are also being compiled that include global ground-truth (GT) information from local, regional, and teleseismic bulletins as well as data obtained through various RSTT workshops in South America, Latin America, Asia, and Africa. Using the new crust and available data, the tomography will be updated for improved coverage and accuracy. Another new feature is the addition of path-dependent uncertainty estimates for all regional phases in RSTT. For a 2/2.5D model like RSTT, we want to have a path-dependent uncertainty determination with a similar dimension as the model itself. This accounts for spatial variations in empirical data which could lead to bias in the model depending on the specific ray path. The goal for RSTT is to have the general user be able to estimate a path-dependent travel time prediction uncertainty on-the-fly using the available software just like users do for actual travel time itself. We also demonstrate validation of the new model and uncertainty estimates using the International Monitoring System stations and Reviewed Event Bulletin events.

Presenting Author: Michael Begnaud

Authors