Data Services Products: EMC-iMUSH_localEQ_Ulberg_2020

Summary

iMUSH_localEQ_Ulberg_2020 contains 3-D Vp and Vs velocity models of the upper crust near Mount St. Helens, WA, obtained using local-source travel-time tomography.

Description

Name iMUSH_localEQ_Ulberg_2020
Title 3-D velocity models of the Mount St. Helens region using local-source travel-time tomography
Type 3-D Tomography Earth Model
Sub Type Compressional and shear-wave velocity (km/s)
Year 2020
Short Description     iMUSH_localEQ_Ulberg_2020 contains 3-D Vp and Vs velocity models of the upper crust near Mount St. Helens, WA, obtained using local-source travel-time tomography. Velocities were obtained using an iterative, nonlinear, conjugate gradient, least squares inversion code with a finite-difference 3-D eikonal equation solver.
Authors:  
Carl Ulberg Earth and Space Sciences, University of Washington, Seattle, WA, USA
Kenneth Creager Earth and Space Sciences, University of Washington, Seattle, WA, USA
Seth Moran United States Geological Survey Cascades Volcano Observatory, Vancouver, WA, USA
Geoffrey Abers Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
Weston Thelen United States Geological Survey Cascades Volcano Observatory, Vancouver, WA, USA
Alan Levander Earth, Environmental, and Planetary Science, Rice University, Houston, TX, USA
Eric Kiser Geosciences, University of Arizona, Tucson, AZ, USA
Brandon Schmandt Earth and Planetary Science, University of New Mexico, Albuquerque, NM, USA
Steven Hansen Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales, Australia
Robert Crosson Earth and Space Sciences, University of Washington, Seattle, WA, USA
 
Previous Model N/A
Reference Model N/A
Model Homepage
 
Model Download iMUSH-localEQ-Ulberg-2020.nc (see metadata), is the netCDF file for the model
 
Model Homepage None
Depth Coverage -5 to 55 km (bsl)
Area Mount St. Helens region (latitude 45.18°/47.34°, longitude -123.71°/-120.69°)
 
Data Set Description    [Ulberg et al., 2020] Five absolute velocity models were produced using arrival times from local earthquakes and active blasts: the ‘normal’ Vp (~29,000 arrival times), ‘normal’ Vs (~4700), ‘matched’ Vp and Vs (~3600; these were calculated in order to obtain a more robust Vp/Vs measurement), and ‘large’ Vp (~74,000) models. Velocity perturbation plots in Ulberg et al. (2020) were made using depth-averaged velocities from these models (Table S2).
 
Model Resolution    The models have 1.2-km node spacing in all directions. Unmasked regions correspond to strong semblance (recovery of checkerboard patterns) for features of 20-km width. Depth resolution is generally best from the surface to 20 km depth.

Depth slice
Depth slices through (a, d, g, and j) Vp, (b, e, h, and k) Vs, and (c, f, and i) Vp/Vs models at 1.0, 5.8. 9.4, and 14.2 km below sea level. Vp and Vs figures show percent variation from a 1‐D model (Figure S8), while Vp/Vs show the velocity ratio. White contours show absolute velocity or ratio value, regions with strong semblance for features with 20‐, 10‐, and 5‐km size are shown with black, dashed black, and dash‐dotted black contours, respectively. Earthquakes used in inversion (filled black circles) and PNSN catalog earthquakes (open black circles) are also shown, for events within 0.6 km of the depth shown. Red triangles indicate position of MSH, Mount Adams, and Mount Rainier; letter codes are the same as in Table 1. For the Vp and Vs figures, the reference velocity at each depth is shown in the lower left corner.

cross sections
W‐E cross sections through MSH for the Vp (a) and Vs (b) models. Contours and earthquakes same as Figure 2. Part (c) shows the average anomaly from the Vp and Vs models, contour shows the ~−3% anomaly contour.

Citations and DOIs

To cite the original work behind this Earth model:

  • Ulberg, C. W., Creager, K. C., Moran, S. C., Abers, G. A., Thelen, W. A., Levander, A., et al. ( 2020). Local source Vp and Vs tomography in the Mount St. Helens region with the iMUSH broadband array. Geochemistry, Geophysics, Geosystems, 21, e2019GC008888. https://doi.org/10.1029/2019GC008888

To cite IRIS DMC Data Products effort:

  • Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern, and R. Aster (2012), Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.

DOI for this EMC webpage:

Credits

Model provided by Carl Ulberg

Timeline

2020-05-06
online

Categories

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