Regional Wave Propagation

In order to further constrain the structure of the lithosphere I have worked on developing methods of using regional wave propagation anomalies.  Both Lg and Sn are seismic phases with propagate primarily through the crust and uppermost mantle respectively.

This research is very important in determining how the international community will monitor a Comprehensive Test Ban Treaty. In order to be able to effectively discriminate between explosive sources and earthquakes.  Because Lg-Pg and Lg-Pn amplitude ratios are typically used in earthquake discrimination it is critical that we develop models that remove the paths effects for both of these two phases.  In order to do this I have worked on developing a tomographic procedure of mapping Lg to Pg ratios. 

In order to map Sn attenuation we used a method of mapping Sn efficiencies.  This technique uses a discrete or quantized data set rather than a continous data set. 

Tests indicate this method accurately maps regions of Sn blockage.  Sn attenuation is a very strong indicator of anomalous hot upper mantle.  Combined with uppermost mantle velocity estimates we have been able to accurately determine regions of thin hot lithospheric mantle beneath the Iranian and Anatolian Plateaus.

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