Wave Propagation in Subducted Lithospheric Slabs
The strongest lateral velocity gradients in the Earth are found in subduction zones. In these regions, the temperatures associated with colder, downgoing slabs can lead to compositional variations and to seismic velocities up to 10 percent higher than the surrounding mantle. These major sources of heterogeneity are known to have significant effects on the travel times and ray trajectories of waves travelling within them (e.g., Sleep, 1973; Davies and Julian, 1972). However, until only recently, the amplitude, extent, and location of the slab velocity anomaly have been examined primarily by observations of travel time anomalies. The deployment of broad-band instrumentation and advances in analysis methods now permit more extensive use of waveform data to model slab effects, including those that are non-geometrical.
KeywordsSubduction Zone Body Wave Deep Earthquake Thin Slab Waveform Distortion
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