Crustal Structure in Alaska From Receiver Function Analysis

Zhang, Ying; Li, Aibing; Hu, Hao

doi:10.1029/2018gl081011

Cited by 28 publications

(65 citation statements)

References 44 publications

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“…Receiver function focused studies, including Miller and Moresi (2018) and Zhang et al (2019), and refraction seismic analysis (Fuis et al, 2008) observe similar variations in crustal thickness from across the different terranes. Allam et al (2017), through double-difference tomography, receiver functions, and fault zone head waves, observed a change in slab dip and Moho depth across the Denali fault zone and show evidence of a low-velocity anomaly in the upper mantle south of the Denali fault.…”

Section: Previous Geophysical Imaging Studiesmentioning

confidence: 84%

“…The ATA has spanned the entire region of Alaska and westernmost Canada, a remarkable accomplishment that enables multiple studies to investigate the subsurface structure of Alaska (e.g., Jiang et al, 2018;Martin-Short et al, 2018;Miller & Moresi, 2018;Zhang et al, 2019). This study focuses on joint inversion of seismic data obtained through ambient noise and earthquakes, including Rayleigh wave ellipticity, phase velocities, and receiver functions.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Previous Geophysical Imaging Studiesmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 99%

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

et al. 2020

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“…Here we used a Moho depth model modified from Miller and Moresi (2018), which was constructed on the basis of P-wave receiver function estimates. They used both the permanent and temporary seismic stations, and so their station coverage is better in south-central Alaska than other receiver function studies (Allam et al, 2017;Brennan et al, 2011;Ferris et al, 2003;O'Driscoll & Miller, 2015;Veenstra et al, 2006;Zhang et al, 2019). In addition to the Moho, we also consider two crustal discontinuities modified from the CRUST1.0 model (Laske et al, 2013) and finally constructed a three-layer crustal model (Figures S3 and S4).…”

Section: Methodsmentioning

confidence: 99%

Structural Heterogeneity in Source Zones of the 2018 Anchorage Intraslab Earthquake and the 1964 Alaska Megathrust Earthquake

Gou

Zhao

Huang

et al. 2020

Geochem Geophys Geosyst

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Structural heterogeneities in subduction zones can affect slip behaviors of the megathrust faults and the generation of intraslab earthquakes. In this work we study the 3‐D seismic structures (Vp, Vs, and Poisson's ratio) in and around the source zones of the 2018 Anchorage intraslab earthquake (Mw 7.1) and the 1964 Alaska megathrust earthquake (Mw 9.2). The Anchorage earthquake occurred in an anomalous zone within the subducting Yakutat/Pacific plate with a higher Poisson's ratio than the normal slab. Above the source zone, the overriding North American plate shows a low Vs and a high Poisson's ratio. These features indicate that strong dehydration occurs in the source zone and released fluids ascend into the overlying crust. Two areas with long‐term slow slip events in the Upper and Lower Cook Inlet predominantly exhibit a high Poisson's ratio in the lowermost portion of the crust and the cold nose of the mantle wedge, whereas a low Poisson's ratio zone is revealed between them, suggesting that their segmentation is possibly related to localized slab‐releasing fluids. In the Prince William Sound, the rupture of the 1964 Great Alaska earthquake initiated beneath a high‐V and high Poisson's ratio zone of the overlying crust and the large slips occurred beneath a low‐Vs and high Poisson's ratio zone, suggesting that lateral heterogeneities of the overriding plate may have played an important role in the nucleation and rupture processes of the Great Alaska earthquake.

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“…Existing studies of the crust and mantle beneath Alaska have been based on a variety of types of data and approaches, including seismic refraction and reflection profiling (e.g., Fuis et al, , ), receiver function analyses (e.g., Ferris et al, ; Miller et al, ; Miller & Moresi, ; O'Driscoll & Miller, ; Rondenay et al, ; Zhang et al, ), body wave tomography for isotropic and anisotropic structures (e.g., Eberhart‐Phillips et al, ; Gou et al, ; Martin‐Short et al, ; Tian & Zhao, ; Zhao et al, ), shear wave splitting studies (e.g., Christensen & Abers, ; Hanna & Long, ; Venereau et al, ; Wiemer et al, ; Yang & Fischer, ), ambient noise tomography (e.g., Ward, ), and earthquake surface wave tomography (e.g., Wang & Tape, ). Some studies combined multiple data sets.…”

Section: Introductionmentioning

confidence: 99%

A 3‐D Shear Velocity Model of the Crust and Uppermost Mantle Beneath Alaska Including Apparent Radial Anisotropy

2019

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This paper presents a model of the 3-D shear velocity structure of the crust and uppermost mantle beneath Alaska and its surroundings on a~50-km grid, including crustal and mantle radial anisotropy, based on seismic data recorded at more than 500 broadband stations. The model derives from a Bayesian Monte Carlo inversion of Rayleigh wave group and phase speeds and Love wave phase speeds determined from ambient noise and earthquake data. Prominent features resolved in the model include the following: (1) Apparent crustal radial anisotropy is strongest across the parts of central and northern Alaska that were subjected to significant extension during the Cretaceous. This is consistent with crustal anisotropy being caused by deformationally aligned middle to lower crustal sheet silicates (micas) with shallowly dipping foliation planes beneath extensional domains. (2) Crustal thickness estimates are similar to those from receiver functions by Miller and Moresi (2018, https://doi.org/10.1785/0220180222). (3) Very thick lithosphere underlies Arctic-Alaska, with high shear wave speeds that extend at least to 120-km depth, which may challenge rotational transport models for the evolution of the region. (4) Subducting lithosphere beneath Alaska is resolved, including what we call the "Barren Islands slab anomaly," an "aseismic slab edge" north of the Denali Volcanic Gap, the "Wrangellia slab anomaly," and Yakutat lithosphere subducting seaward of the Wrangell volcanic field. (5) The geometry of the Alaskan subduction zone generally agrees with the slab model Alaska_3D 1.0 of Jadamec and Billen (2010, https://doi.org/10.1038/nature09053) except for the Yakutat "slab shoulder region," which is newly imaged in our model.

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Crustal Structure in Alaska From Receiver Function Analysis

Cited by 28 publications

References 44 publications

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

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

Structural Heterogeneity in Source Zones of the 2018 Anchorage Intraslab Earthquake and the 1964 Alaska Megathrust Earthquake

A 3‐D Shear Velocity Model of the Crust and Uppermost Mantle Beneath Alaska Including Apparent Radial Anisotropy

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