Temporal variability in the propagation of infrasonic waves over Hawaii and Alaska

Abstract

Temporally varying atmospheric temperature and wind velocity data from ground level up to heights of 250 km are used to compute travel time curves and azimuth deviations for acoustic waves propagating over the CTBT infrasonic array sites of Hawaii and Alaska. An enhanced formulation of the tau-p method [Garces et al., Geophys. J. Int. (1998)] permits theoretical estimates of travel times and azimuth deviations for infrasonic waves traveling through a stratified, windy atmosphere. Atmospheric data for the season of Winter is obtained from the Naval Research Laboratory MSISE-90 and HWM-93 models, which include tidal and geomagnetic effects. These data will be supplemented with ground-based and satellite-based atmospheric data. An ensemble of circumstances, encompassing infrasonic wave propagation through anomalous environmental conditions as well as studies on site-specific effects, will be presented. Based on the predicted phases, effective detection and source inversion algorithms will be developed at each array.