This manuscript is available here. Data and tomographic scripts (MATLAB) with pbs scripts for submission on a supercomputer are available here. Please contact me if you are interested in one of the Julia implementations of the code that a couple of different graduate students have put together.

Attenuation tomography of the upper mantle in the salton trough

The image of the right is a cross-section across the Salton Trough (see below) showing stronger attenuation in red and weaker in white. ζ is 1000/Qp.

Location of the tomographic study - the Salton Trough is the point of transition from the San Andreas to the north and extension in the Gulf of California to the South. Thick sediments cover the region, and low velocities throughout the Gulf of Cali…

Location of the tomographic study - the Salton Trough is the point of transition from the San Andreas to the north and extension in the Gulf of California to the South. Thick sediments cover the region, and low velocities throughout the Gulf of California suggest upwelling driven by something other than plate spreading. The data in this study is taken from the SSIP array (http://ds.iris.edu/gmap/#network=XD&starttime=2011-01-01T00:00:00&endtime=2013-12-31T23:59:59&planet=earth). The cross-section in the first at the top of this page is defined by the black line in panel B.

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Dynamic upwelling

So what did we find?

The attenuating feature is sufficiently attenuating that we attribute it to a melting column like that found beneath mid-ocean ridges. More than that, the feature is sharply bounded and becomes narrow at depth. That’s inconsistent with a model where the upwelling is driven by extension - but precisely what models of upwelling driven by buoyancy predict.