High Resolution Imagery of the Source Physics Experiment at Rock Valley
Description:
We use several methods of seismic interferometry to obtain highly detailed images at the site of the Source Physics Experiment (SPE), with a particular focus on the site of the upcoming experiment at Rock Valley.
SPE is a series of experiments in varying geologies with the objective of obtaining a physics-based understanding of how seismic waves are created at and scattered near seismic sources. The first two phases were conducted in granite and alluvium geologies, respectively. The source for the final phase will be co-located with a known shallow earthquake, allowing direct comparison of earthquake and explosive sources.
A number of dense arrays have been deployed during the three phases of the SPE experiment, allowing refined imagery in the different environments. They resolve the spatial wavefield, allowing direct measurement of amplitudes and wavespeeds. This enables sharp imagery of the seismic velocities (Vs and Vp) and attenuation (Qs and Qp), which are then used in waveform modeling calculations and experimental predictions.
3D modeling was done using interferometry on a combination of active and passive seismic sources. Interferometry is a particularly powerful means of isolating the energy within the scattering wavefield, and obtains an estimate of the Green's function (GF). The GFs estimated using interferometry are very precise, any variations are directly related to changes in the subsurface over time.
We apply several interferometric techniques: Source interferometry (SI) uses the explosions as rich sources of high frequency, high signal energy. Coda interferometry (CI) isolates the energy from the scattered wavefield. Ambient noise correlation (ANC) uses the energy of the ambient background field. In each case, the data recorded at one seismometer are correlated with the data recorded at another to obtain an estimate of the Green's function (GF) between the two. These GFs are then inverted to obtain the final seismic image. The objective is to obtain a 3D model that is precise enough to calculate synthetics matching the scattering effects seen in the data.
Session: Exploiting Explosion Sources: Advancements in Seismic Source Physics [Poster]
Type: Poster
Date: 4/19/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Eric Matzel
Student Presenter: No
Invited Presentation:
Authors
Eric Matzel Presenting Author Corresponding Author matzel1@llnl.gov Lawrence Livermore National Laboratory |
Arben Pitarka pitarka1@llnl.gov Lawrence Livermore National Laboratory |
William Walter walter5@llnl.gov Lawrence Livermore National Laboratory |
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High Resolution Imagery of the Source Physics Experiment at Rock Valley
Category
General Session