Seismic Attenuation and Velocity Measurements of the Uppermost Mantle Beneath the Central and Eastern United States and Implications for the Temperature of the North American Lithosphere

Yassminh, Rayan; Laphim, Parichat; Sandvol, Eric

doi:10.1029/2019jb017728

Cited by 3 publications

(1 citation statement)

References 107 publications

(147 reference statements)

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“…Previous studies of regional CENA attenuation models are numerous; recent works include Cramer (2017), Cramer and Al Noman (2016), Bisrat et al (2014), Yassminh et al (2020), Chapman and Conn (2016), Guo and Chapman (2019), Pasyanos (2013), Gallegos et al (2014), and NGA-East (PEER, 2015). The NGA-East project was a multi-disciplinary research project managed by Christine Goulet with the objective to develop a new ground motion characterization (GMC) model for CENA.…”

Section: Introductionmentioning

confidence: 99%

Regional attenuation models in Central and Eastern North America using the NGA-East database

Bayless

2021

Earthquake Spectra

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The anelastic attenuation term found in ground motion prediction equations (GMPEs) represents the distance dependence of the effect of intrinsic and scattering attenuation on the wavefield as it propagates through the crust and contains the frequency-dependent quality factor, [Formula: see text], which is an inverse measure of the effective anelastic attenuation. In this work, regional estimates of [Formula: see text] in Central and Eastern North America (CENA) are developed using the NGA-East regionalization. The technique employed uses smoothed Fourier amplitude spectrum (FAS) data from well-recorded events in CENA as collected and processed by NGA-East. Regional [Formula: see text] is estimated using an assumption of average geometrical spreading applicable to the distance ranges considered. Corrections for the radiation pattern effect and for site response based on [Formula: see text] result in a small but statistically significant improvement to the residual analysis. Apparent [Formula: see text] estimates from multiple events are combined within each region to develop the regional models. Models are provided for three NGA-East regions: the Gulf Coast, Central North America, and the Appalachian Province. Consideration of the model uncertainties suggests that the latter two regions could be combined. There were not sufficient data to adequately constrain the model in the Atlantic Coastal Plain region. Tectonically stable regions are usually described by higher [Formula: see text] and weaker frequency dependence ([Formula: see text]), while active regions are typically characterized by lower [Formula: see text] and stronger frequency dependence, and the results are consistent with these expectations. Significantly different regional [Formula: see text] is found for events with data recorded in multiple regions, which supports the NGA-East regionalization. An inspection of two well-recorded events with data both in the Mississippi embayment and in southern Texas indicates that the Gulf Coast regionalization by Cramer in 2017 may be an improvement to that of NGA-East for anelastic attenuation. The [Formula: see text] models developed serve as epistemic uncertainty alternatives in CENA based on a literature review and a comparison with previously published models.

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Section: Introductionmentioning

confidence: 99%

Regional attenuation models in Central and Eastern North America using the NGA-East database

Bayless

2021

Earthquake Spectra

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Detecting lithospheric discontinuities beneath the Mississippi Embayment using S-wave receiver functions

Saxena

Langston

2021

Geophysical Journal International

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Identifying upper-mantle discontinuities in the Central and Eastern US is crucial for verifying models of lithospheric thinning and a low-velocity anomaly structure beneath the Mississippi Embayment. In this study, S-wave receiver functions (SRFs) were used to detect lithospheric boundaries in the embayment region. The viability of SRFs in detecting seismic boundaries was tested before computing them using the earthquake data. A careful analysis using a stochastic noise and coda model on the synthetics revealed that a negative velocity contrast could be detected with certainty at low to moderate noise levels after stacking. A total of 31518 SRFs from 688 earthquakes recorded at 174 seismic stations including the Northern Embayment Lithospheric Experiment, EarthScope Transportable Array and other permanent networks were used in this study. Common depth point stacks of the SRFs in 1○ × 1○ bins indicated a continuous and broad S-to-p converted phase (Sp) arrival corresponding to a negative velocity contrast at depths between 50 and 100 km. The observed negative Sp phase is interpreted as a mid-lithospheric discontinuity (MLD), and several possible origins of the velocity drop corresponding to the MLD are explored. After quantitative analysis, a combination of temperature, water content, and melt content variations are attributed to explain the observed MLD in this study. The observations and interpretations in this study support the previous claims of a MLD in the Central and Eastern US and provide a possible mechanism for its origin.

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Evolution, Modification, and Deformation of Continental Lithosphere: Insights from the Eastern Margin of North America

Long

2024

Annual Review of Earth and Planetary Sciences

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Continental lithosphere is deformed, destroyed, or otherwise modified in several ways. Processes that modify the lithosphere include subduction, terrane accretion, orogenesis, rifting, volcanism/magmatism, lithospheric loss or delamination, small-scale or edge-driven convection, and plume-lithosphere interaction. The eastern North American margin (ENAM) provides an exceptional locale to study this broad suite of processes, having undergone multiple complete Wilson cycles of supercontinent formation and dispersal, along with ∼200 Ma of postrift evolution. Moreover, recent data collection efforts associated with EarthScope, GeoPRISMS, and related projects have led to a wealth of new observations in eastern North America. Here I highlight recent advances in our understanding of the structure of the continental lithosphere beneath eastern North America and the processes that have modified it through geologic time, with a focus on recent geophysical imaging that has illuminated the lithosphere in unprecedented detail. ▪ Eastern North America experienced a range of processes that deform, destroy, or modify continental lithosphere, providing new insights into how lithosphere evolves through time. ▪ Subduction and terrane accretion, continental rifting, and postrift evolution have all played a role in shaping lithospheric structure beneath eastern North America. ▪ Relict structures from past tectonic events are well-preserved in ENAM lithosphere; however, lithospheric modification that postdates the breakup of Pangea has also been significant. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 52 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Seismic Attenuation and Velocity Measurements of the Uppermost Mantle Beneath the Central and Eastern United States and Implications for the Temperature of the North American Lithosphere

Cited by 3 publications

References 107 publications

Regional attenuation models in Central and Eastern North America using the NGA-East database

Regional attenuation models in Central and Eastern North America using the NGA-East database

Detecting lithospheric discontinuities beneath the Mississippi Embayment using S-wave receiver functions

Evolution, Modification, and Deformation of Continental Lithosphere: Insights from the Eastern Margin of North America

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