Allen CV
Seismo Lab
Earth & Planetary
UC Berkeley


P- and S-velocity models for the US integrating body- and surface-wave constraints


More on the DNA models

Maps and cross sections summarizing the Wyoming Province. Maps are centered on Wyoming. See Fig 6 Porritt et al 2014

Model highlights:

  • The DNA13 model contains four estimates of the relative seismic wave-speed (1 P and 3 S) in the US upper mantle.
  • The P, SH, and SV components utilize finite-frequency kernels and relative first arrival times for a set of body-wave only models.
  • The SV-Joint component utilizes the SV component relative arrival times, teleseismically determined phase velocities, and ambient noise derived phase velocities in a single inversion.
  • The Wyoming Province is imaged as thicker lithosphere than the surrounding continent, but with a low velocity zone due to the Yellowstone Plume. This thick lithosphere is coincident with the dipping high velocity body imaged by Yuan et al. with the CD-ROM array, but extends further eastward than the earlier experiment could resolve.
  • The Llano province in central Texas is separated from the Laurentia Craton by the Southern Oklahoma Aulacogen which exhibits thin lithosphere under the basin. A high velocity body imaged under the Llano Province dips to the northeast and strikes along the Grenville Front suggesting it originated during the Grenville Orogeny at ~1.1Ga.
  • The mantle structure through the transition zone displays markedly high velocity anomalies suggesting a tenuous subduction path for the Farallon slab.

Maps and cross-sections highlighting the Llano Provice. Maps are centered on Texas. See Fig 7.

Map and cross-section highlighting the deep slab under the eastern US. See Fig 8.

Model specifications:

  • Parameters: DNA13 contains 4 estimates of relative wave-speed (P, SH, SV, and SV-J).
  • Coverage: Good resolution extends from the Pacific coast to the Great Plains (~75 deg W), from the Mexican boarder (27 deg N) to the Canadian boarder (49 deg N).
  • Data source: More than 2200 stations where used from the USArray transportable array, regional seismic networks, and temporary seismic deployments.
  • Data type: Relative traveltimes of teleseismic body waves (P and S) from over 350 earthquakes, surface wave phase velocity measurements over 167 eartqhuakes, and 5 years of ambient seismic noise drived phase velocities were used to constrain the model.
  • Inversion: Finite frequency sensitivity kernels and phase velocity sensitivity kernels are used in a damped (but not smoothed) LSQR inversion.
  • Resolution: The model can resolve mantle structure to a depth of ~1000 km and with a lateral and vertical resolution of ~250km. In the upper ~200km where the surface waves provide additional constraints the lateral resolution is ~100km and the vertical resolution is ~10km.

Published in Porritt, Allen and Pollitz, EPSL ...more.