Ryan Modrak
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View article: MTUQ: a framework for estimating moment tensors, point forces, and their uncertainties
MTUQ: a framework for estimating moment tensors, point forces, and their uncertainties Open
SUMMARY We introduce MTUQ, an open-source Python package for seismic source estimation and uncertainty quantification, emphasizing flexibility and operational scalability. MTUQ provides MPI-parallelized grid search and global optimization …
View article: Crustal waveform modeling [Slides]
Crustal waveform modeling [Slides] Open
Increasing scatterer amplitude relative to backgroundNo superimposed scatterers 5 percent variance 10 percent variance
View article: Machine Learning Inference of Random Medium Properties
Machine Learning Inference of Random Medium Properties Open
Earth materials are heterogeneous across a range of spatial scales, but the resolvability of small structures is limited by sparse data coverage, noise, bandlimitedness, and other difficulties. In practice, heterogeneities below a certain …
View article: Machine Learning Inference of Random Medium Properties
Machine Learning Inference of Random Medium Properties Open
Earth materials are heterogeneous across a range of spatial scales, but the resolvability of small structures is limited by sparse data coverage, noise, bandlimitedness, and other difficulties. In practice, heterogeneities below a certain …
View article: Reply to “Comment on ‘Multievent Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption’ by Julien Thurin, Carl Tape, and Ryan Modrak” by Fred F. Pollitz, Ricardo Garza-Giron, and Thorne Lay
Reply to “Comment on ‘Multievent Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption’ by Julien Thurin, Carl Tape, and Ryan Modrak” by Fred F. Pollitz, Ricardo Garza-Giron, and Thorne Lay Open
View article: <i>Erratum to</i> Multi-Event Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption
<i>Erratum to</i> Multi-Event Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption Open
View article: Deep-learning-guided high-resolution subsurface reflectivity imaging with application to ground-penetrating radar data
Deep-learning-guided high-resolution subsurface reflectivity imaging with application to ground-penetrating radar data Open
SUMMARY Subsurface reflectivity imaging is one of the most important geophysical characterization methods for revealing subsurface structures. In many cases, accurate subsurface reflectivity imaging is challenging because of, for example, …
View article: Multi-Event Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption
Multi-Event Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption Open
The eruption of the Hunga Tonga–Hunga Ha’apai submarine volcano on 15 January 2022 produced a variety of geophysical responses, including a significant seismic signal. We study the seismic source process of this event by inverting for mome…
View article: SREMI: Super-resolution electromagnetic imaging with single-channel ground-penetrating radar
SREMI: Super-resolution electromagnetic imaging with single-channel ground-penetrating radar Open
View article: Strong Upper‐Plate Heterogeneity at the Hikurangi Subduction Margin (North Island, New Zealand) Imaged by Adjoint Tomography
Strong Upper‐Plate Heterogeneity at the Hikurangi Subduction Margin (North Island, New Zealand) Imaged by Adjoint Tomography Open
We use earthquake‐based adjoint tomography to invert for three‐dimensional structure of the North Island, New Zealand, and the adjacent Hikurangi subduction zone. The study area, having a shallow depth to the plate interface below the Nort…
View article: Spectral Element Modeling of Acoustic to Seismic Coupling Over Topography
Spectral Element Modeling of Acoustic to Seismic Coupling Over Topography Open
Acoustic waves in the atmosphere are commonly recorded on seismometers as they couple into the ground. These signals, here called ground coupled airwaves, are not commonly considered in numerical modeling of infrasound propagation, which o…
View article: Rayleigh Wave Propagation in the Bighorn Mountains Region, Wyoming
Rayleigh Wave Propagation in the Bighorn Mountains Region, Wyoming Open
Short-period Rayleigh waves, Rg, provide strong constraints on the depth of shallow seismic events and are of interest for monitoring small explosions. Characterizing the seismic sources that generate Rg requires an understanding of how sh…
View article: Strong upper-plate heterogeneity at the Hikurangi subduction margin (North Island, New Zealand) imaged by adjoint tomography
Strong upper-plate heterogeneity at the Hikurangi subduction margin (North Island, New Zealand) imaged by adjoint tomography Open
We use earthquake-based adjoint tomography to invert for three-dimensional structure of the North Island, New Zealand, and the adjacent Hikurangi subduction zone. The study area, having a shallow depth to the plate interface below the Nort…
View article: Estimates of Acoustic to Seismic Coupling Over Topography from Time Domain Numerical Modeling [Slides]
Estimates of Acoustic to Seismic Coupling Over Topography from Time Domain Numerical Modeling [Slides] Open
incidence angle, with very high admittance values for near-vertical incidence (maximum ≈78%). Energy admittance calculations at shallow incidence angles are much smaller (less than 1%). In simulations over the complex topography of Sakuraj…
View article: Waveform Modeling and Simulation for Crustal Phases [Slides]
Waveform Modeling and Simulation for Crustal Phases [Slides] Open
Goals for this project are to: numerically simulate wave propagation in layered crustal models with laterally-varying structure; Investigate seismic phases Pg and Pn; help understand the variability and complexity of these phases in record…
View article: Waveform Modeling and Simulation for Crustal Phases [Slides]
Waveform Modeling and Simulation for Crustal Phases [Slides] Open
View article: Double-difference measurements in global full-waveform inversions
Double-difference measurements in global full-waveform inversions Open
SUMMARY We demonstrate double-difference (DD) tomography, a method involving differential measurements between stations, for 2-D and 3-D adjoint inversions based on realistic source–receiver distributions, with a focus on the global scale.…
View article: Balancing unevenly distributed data in seismic tomography: a global adjoint tomography example
Balancing unevenly distributed data in seismic tomography: a global adjoint tomography example Open
SUMMARY The uneven distribution of earthquakes and stations in seismic tomography leads to slower convergence of nonlinear inversions and spatial bias in inversion results. Including dense regional arrays, such as USArray or Hi-Net, in glo…
View article: A New Generation of Earth Mantle Model from Global Adjoint Tomography
A New Generation of Earth Mantle Model from Global Adjoint Tomography Open
View article: Seismic waveform inversion best practices: regional, global and exploration test cases
Seismic waveform inversion best practices: regional, global and exploration test cases Open
Reaching the global minimum of a waveform misfit function requires careful choices about the nonlinear optimization, preconditioning and regularization methods underlying an inversion. Because waveform inversion problems are susceptible to…