The moho depth variations under the LASA and their effect on dT/dΔ measurements

Abstract

The LASA array in Montana was used to measure the slope of the travel-time curve (dT/dΔ) for events with epicenters to the northwest and southeast. Lateral inhomogeneities under the array introduce large relative arrival time errors (station residuals). A model for the crust under LASA is proposed which can explain the station residuals. This crustal model accounts for the major differences between the measured and Jeffreys-Bullen (J-B) dT/dΔ values. The model was used to correct the measured dT/dΔ profiles for the crustal effect.