Shear Velocity Model of Alaska Via Joint Inversion of Rayleigh Wave Ellipticity, Phase Velocities, and Receiver Functions Across the Alaska Transportable Array

Abstract

Through the Alaska Transportable Array deployment of over 200 stations, we create a 3‐D tomographic model of Alaska with sensitivity ranging from the near surface (<1 km) into the upper mantle (~140 km). We perform a Markov chain Monte Carlo joint inversion of Rayleigh wave ellipticity and phase velocities, from both ambient noise and earthquake measurements, along with receiver functions to create a shear wave velocity model. We also use a follow‐up phase velocity inversion to resolve interstation structure. By comparing our results to previous tomography, geology, and geophysical studies we are able to validate our findings and connect localized near‐surface studies with deeper, regional models. Specifically, we are able to resolve shallow basins, including the Copper River, Cook Inlet, Yukon Flats, Nenana, and a variety of other shallower basins. Additionally, we gain insight on the interaction between the upper mantle wedge, asthenosphere, and active and nonactive volcanism along the Aleutians and Denali volcanic gap, respectively. We observe thicker crust beneath the Brooks Range and south of the Denali fault within the Wrangellia Composite Terrane and thinner crust in the Yukon Composite Terrane in interior Alaska. We also gain new perspective on the Wrangell Volcanic Field and its interaction between surrounding asthenosphere and the Yakutat Terrane.

Shallow Crustal Shear Velocity and Vp/Vs Across Southern California: Joint Inversion of Short‐Period Rayleigh Wave Ellipticity, Phase Velocity, and Teleseismic Receiver Functions

“…On average, there are ∼2,000 models in each posterior. Details about the number of iterations, avoiding the edges of prior distributions, and data uncertainties can be found in previous works (Berg et al, 2018(Berg et al, , 2020Shen et al, 2012).…”

Amphibious Shear Wave Structure Beneath the Alaska‐Aleutian Subduction Zone From Ambient Noise Tomography

“…There are also seismic studies which investigated subducting zone structures using body wave tomography (e.g., Eberhart‐Phillips, et al., 2006; Gou et al., 2019), surface wave tomography (e.g., Berg et al., 2020; Feng et al., 2020; Feng & Ritzwoller, 2019; Jiang et al., 2018; Nayak et al., 2020; Wang & Tape, 2014; Y. Wang & Tape, 2014; Ward, 2015), receiver functions (e.g., Miller & Moresi, 2018; Zhang et al., 2019) and shear wave splitting (e.g., Hanna & Long, 2012; Venereau et al., 2019). Important isotropic structures, including the geometry of the subducting Pacific slab and the Yakutat microplate, are resolved by numerous seismic tomography studies (e.g., Berg et al., 2020; Feng & Ritzwoller, 2019; Gou et al., 2019; Jiang et al., 2018; Nayak et al., 2020). And the distribution of crustal radial anisotropy, which reflects the mid‐Cretaceous extensional deformation, is imaged by Feng and Ritzwoller (2019).…”

Surface‐Wave Tomography of the Northern Canadian Cordillera Using Earthquake Rayleigh Wave Group Velocities

“…tropy studies showing a rotation of fast-axis directions around the Pacific slab (e.g., Venereau et al, 2019). Some seismic tomography models also support this hypothesis as they do not show a slab signature beneath the WVF (Berg et al, 2020;Martin-short et al, 2018). Therefore, questions remain regarding the detailed relationship between subduction and volcanism in the WVF in view of recent geophysical studies such as what controls the observed volcanism across the WVF?…”