منابع مشابه
Spatial variations of P wave attenuation in the mantle beneath North America
[1] We estimate the spatial variation of the seismic parameter t* using teleseismic (epicentral distance = 30 –85 ) P wave spectra of about 200 deep (focal depths > 200 km) earthquakes recorded by 378 broadband seismometers in the United States and Canada. Relative P wave spectral ratios up to 1 Hz for about 63,000 station pairs with high signal-to-noise ratio and impulsive P waveforms are inve...
متن کاملCrust and upper mantle discontinuity structure beneath eastern North America
[1] Crust and mantle discontinuities across the eastern margin of the North American craton were imaged using P to S converted phase receiver functions recorded by the Missouri to Massachusetts Broadband Seismometer Experiment. Crustal structure constrained by modeling Moho conversions and reverberations shows a variation of Moho depth from a minimum of 30 km near the Atlantic coast to depths o...
متن کاملMechanisms for synoptic variations of atmospheric CO2 in North America, South America and Europe
Synoptic variations of atmospheric CO2 produced by interactions between weather and surface fluxes are investigated mechanistically and quantitatively in midlatitude and tropical regions using continuous in-situ CO2 observations in North America, South America and Europe and forward chemical transport model simulations with the Parameterized Chemistry Transport Model. Frontal CO2 climatologies ...
متن کاملReconstructing Farallon plate subduction beneath North America back to the Late Cretaceous.
Using an inverse mantle convection model that assimilates seismic structure and plate motions, we reconstruct Farallon plate subduction back to 100 million years ago. Models consistent with stratigraphy constrain the depth dependence of mantle viscosity and buoyancy, requiring that the Farallon slab was flat lying in the Late Cretaceous, consistent with geological reconstructions. The simulatio...
متن کاملMapping attenuation beneath North America using waveform cross- correlation and cluster analysis
[1] We measure seismic attenuation beneath North America using waveform cross-correlation and cluster analysis, and obtain images of the laterally varying anelastic structure of the upper mantle. Cluster analysis improves attenuation measurements by systematically comparing only highly similar waveforms, which reduces bias from scattering, directional differences in source functions, and source...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research
سال: 2009
ISSN: 0148-0227
DOI: 10.1029/2008jb005949