Data Services Products: EMC-FWT_SouthAmerica_2022 3-D shear-wave velocity model of the South American subduction margin

Summary

A high-resolution shear-wave velocity model from immediately offshore to the backarc in South America, using advanced full-wave ambient noise tomography

Description

Name FWT_SouthAmerica_2022
Title 3-D shear-wave velocity model of the South American subduction margin
Type 3-D Tomography Earth Model
Sub Type Shear-wave velocity (km/s)
Year 2022
Data Revision r0.0 (revision history)
 
Short Description   A high-resolution shear-wave velocity model from immediately offshore to the backarc in South America, using advanced full-wave ambient noise tomography
 
Authors: Meng Liu, Department of Geosciences, University of Massachusetts Amherst, 627 North Pleasant Street. Amherst, MA 01003, E-mail: mengliu@umass.edu

Haiying Gao, Department of Geosciences, University of Massachusetts Amherst, 627 North Pleasant Street. Amherst, MA 01003, E-mail: haiyinggao@umass.edu
 
Reference Model The initial reference model is composed of the 2°×2° global shear-wave velocity model (Shapiro & Ritzwoller, 2002) for the top 396 km and the 1-D AK135 velocity model (Kennett et al., 1995) at greater depths.
 
Model Download FWT-SouthAmerica-2022.r0.0.nc (see metadata) in the Polar Stereographic Projection and in netCDF 3 Classic format.
 
Depth Coverage 0–200 km
 
Area South America (latitude: -10.0°/-56 °; longitude: -78°/-62°)
 
Data Set Description Our model extends from longitude 62°W to 78°W, latitude 10°S to 56°S, and depths from the surface down to 200 km. We parametrize the model domain into 0.04° × 0.04° in the longitudinal and latitudinal directions. The vertical grid spacing is depth dependent, which increases from ~1.5 km near the surface to ~5.4 km at 200 km depth.
 
 

Figure 1
Figure 1. Shear-wave velocities at multiple depths. The thick black line represents the trench, and the white contours represent the plate interface at depths of 50, 100, and 150 km (Hayes et al., 2018). The white boxes 1, 2, 3, and 4 represent the four slab segments inferred from our model. The dashed lines at the ends of boxes 1 and 4 represent a limited recovery of the slab. The gray shaded areas mask the regions with low model resolutions based on checkerboard resolution tests. The cyan outlines in (a) and (b) represent the Vs = 3.45 km/s contours, which define the extent of the low-velocity anomalies. The magenta lines in (h) represent the profile locations.

Figure 2
Figure 2. Vs profiles at depths of 5–200 km. The surface topography is plotted atop each profile with a vertical exaggeration of 5. Red triangles mark the projected volcanoes. The white lines represent the plate interface, and red lines represent the Moho depth of CRUST 1.0. The gray dots represent the earthquakes. The four slab segments 1, 2, 3, and 4 are labeled. The crustal low-velocity anomalies (LVA) are highlighted using the Vs = 3.45 km/s contours. The other high-velocity structures described in the content are highlighted as HV. The gray shaded areas at depths of 180–200 km mask the regions with reduced model resolutions. There is no exaggeration of vertical profiles.

Citations and DOIs

To cite the original work behind this Earth model:

  • Liu, M., & Gao, H. (2022). Three- dimensional variation of the slab geometry within the South American subduction system. Geophysical Research Letters, 49, e2021GL095924. https://doi.org/10.1029/2021GL095924

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: https://doi.org/10.17611/dp/emc.2022.fwtsamerica.2022.1


References

  • Shapiro, N. M., and M. H. Ritzwoller (2002), Monte-Carlo inversion for a global shear-velocity model of the crust and upper mantle, Geophys. J. Int., 151(1), 88-105, https://doi.org/10.1046/j.1365-246X.2002.01742.x
  • Hayes, G. P., Moore, G. L., Portner, D. E., Hearne, M., Flamme, H., Furtney, M., & Smoczyk, G. M. (2018). Slab2, a comprehensive subduction zone geometry model. Science, 362(6410), 58–61. https://doi.org/10.1126/science.aat4723
  • Kennett, B. L. N., Engdahl, E. R. Traveltimes for global earthquake location and phase identification. Geophys. J. Int., 105: 429-465 (1991)

Credits

  • r0.0 model provided by Meng Liu.

Revision History

revision r0.0: uploaded October 06, 2022.

Timeline

2022-10-06
online

Contact

Categories

Tags

Earth Models data Shear Wave Velocity EMC tomography velocity depth South America full-wave ambient noise tomography

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