1 Hz Lg Q tomography in central Asia

We have applied tomographic techniques to a data set of over 1700, regional distance, L g amplitudes from 12 stations for paths inside a 30° by 40° region of Central Asia. Our purpose is to create high resolution path correction maps for use in regional distance source discrimination and magnitude determination, as well as to study L g propagation characteristics in one of the most heterogeneous portions of the earth. For 1.0 Hz data, tomography reduced variance 33%, relative to a best fit, uniform Q model. L g Q varied with geologic region, with low values in Tibet, the Tien Shan and the Pamir range ( Q =200 to 400), intermediate values in basins such as the Tarim ( Q =500) and high values for platforms and older crust (Q>800). The relatively efficient propagation across the Tarim differs from the poor propagation that is generally observed across sedimentary basins.