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Accurate Modeling of Seismic Waveforms of PE1-A Explosion

Description: 

Our research aims to provide high-fidelity seismic modeling of the PE1-A chemical explosion, conducted in October 2023 at the Nevada National Security Site, with a focus on understanding the coupling of the explosion to the ground. For such modeling, we use the code HOSS developed at LANL to model the near-source regime. HOSS is coupled to two seismic codes to model seismic waveforms at large distances, one based on the reflectivity method (Kennett, 1985) and the other based on the spectral element method, SPECFEM3D. HOSS combines finite-element analysis of continua with discrete-element transient dynamics allowing one to explicitly model fracture and spallation processes. Several material models have been developed to describe the explosion emplacement conditions that are important to accurate modeling of the coupling efficiency of the PE1 chemical explosion series to the ground.

HOSS and the seismic codes are coupled using the representation theorem which states that a seismic source can be replaced by the time-history of the wavefield recorded on a surface surrounding the source volume. The two seismic codes use this recorded information to fully determine the wavefield in the remaining full space. The coupling surface is chosen to be beyond the transition from non-linear to pure elastic domain. This transition is typically less than one hundred meters away from the source centroid. Kinematic energy must be preserved through the coupling for accurate modeling. This may be challenging due to different sampling requirements of the two types of modeling, as well as by the fact that the seismic codes and the hydrodynamic codes may not consider the same velocity model at the coupling surface. HOSS modeling is performed in a layered model based on the local Geological Framework Model which considers multiple Tertiary tuffs. Seismic modeling at distances beyond 10 km will typically use 1D crustal models or 3D regional models that do not incorporate the local layering. In this paper, we will explore the accuracy of our coupling interface and propose a correction to be applied in the case of a velocity model mismatch.

Session: Advancements in Forensic Seismology and Explosion Monitoring [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Carene

Student Presenter: No

Invited Presentation: 

Poster Number: 88

Authors