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Wiggins, SM, Dorman LRM, Cornuelle BD, Hildebrand JA.  1996.  Hess Deep rift valley structure from seismic tomography. Journal of Geophysical Research-Solid Earth. 101:22335-22353.   10.1029/96jb01230   AbstractWebsite

We present results from a seismic refraction experiment conducted across the Hess Deep rift valley in the equatorial east Pacific. P wave travel times between seafloor explosions and ocean bottom seismographs are analyzed using an iterative stochastic inverse method to produce a velocity model of the subsurface structure. The resulting velocity model differs from typical young, fast spreading, East Pacific Rise crust by approximately +/-1 km/s with slow velocities beneath the valley of the deep and a fast region forming the intrarift ridge. We interpret these velocity contrasts as lithologies originating at different depths and/or alteration of the preexisting rock units. We use our seismic model, along with petrologic and bathymetric data from previous studies, to produce a structural model. The model supports low-angle detachment faulting with serpentinization of peridotite as the preferred mechanism for creating the distribution and exposure of lower crustal and upper mantle rocks within Hess Deep.

Cornuelle, B, Howe BM.  1987.  High Spatial-Resolution in Vertical Slice Ocean Acoustic Tomography. Journal of Geophysical Research-Oceans. 92:11680-11692.   10.1029/JC092iC11p11680   AbstractWebsite

Most studies of ocean acoustic tomography have assumed that little horizontal information is available from the many acoustic multipath travel times observed in a single vertical plane (slice) between source and receiver moorings. There is in fact significant small-scale information present in such data sets. We examine single vertical slice tomography in spectral terms, and show that the acoustic measurements resemble a high-pass filter, which is more sensitive to small scales (shorter than 100 km) than to longer scales, with the exception of the mean, which is well measured. The sensitivity extends to scales smaller than 10 km, in theory, although the level of the ocean energy spectrum is so low at these scales that even small data errors limit the measurement. We use analytical calculations supplemented by numerical simulations with realistic data sets to show that accurate reconstructions of the high wave number features are possible out to the limits of the parameterization (9.2-km wavelength) when the power spectrum of the ocean features is white or red, the total measurement error is 1 ms, and multiple receivers are used. The ultimate limit of spatial resolution may be smaller still, depending on array configuration, measurement errors, and the shape of the power spectrum.