Tomographic images of a mantle circulation model

Abstract

Sampling convection in the Earth's mantle by seismic tomography is difficult as evidenced by the uneven distribution of seismic stations and events with some regions being well imaged compared to others. Here we quantitatively explore tomographic filtering on Earth structure by tracing ISC P-body-wave data through a computer simulation of mantle circulation which accounts for internal heating of the mantle by radioactive decay, heatflux from the core, a depthwise increase in viscosity, and plate motion history of the past 120 million years. The travel time residuals are inverted by solving jointly for structure and hypocentral parameters with explicit damping and smoothing. We recover the Farallon and Tethys slabs as well as some low velocity anomalies associated with hot upwelling flow suggesting that tomographic filtering is probably minor in areas of high ray density.