Mapping a part of Neuquén basin in Argentina by global-phase H/V spectral ratio

Abstract

We investigated the applicability of global phases (epicentral distances of ≥ 120° and ≥ 150°) for the H/V spectral ratio to identify the fundamental resonance frequency. We applied the method to delineate a part of Neuquén basin in Argentina without the need for active seismic sources. We obtained fairly identifiable fundamental resonance frequencies in the range 0.15 Hz to 2.5 Hz. Receiver-side resonances were pronounced by stacking the H/V spectral ratio over many earthquake recordings. By doing so, the same fundamental resonances were found by using different window (P and S-phases) as well as different epicentral distances (≥ 120° and ≥ 150°). Our result, assuming average velocity, shows identical features in comparison with both the Bouguer anomaly and the active seismic profile nearby, indicating that our method is reliable. The method we demonstrate here can be applied in the fields particularly when the seismic array of long-term purposes is available.