Infrasound Observations at Bahía de Banderas, Western Mexico

ABSTRACT We studied the infrasound environment in Bahía de Banderas, the largest open bay in Mexico and one of the largest in the world. We were interested in answering three questions: How saturated is the environment with infrasonic signals? What are the typical sources of infrasound and their characteristics? Do infrasound signals provide new information to characterize phenomena of interest? The infrasound data were acquired by deploying three infrasonic sensors. We detected infrasound signals using catalogs of known phenomena (i.e., earthquakes, rainfall, and thunders) and implemented automatic detection algorithms. Finally, the signals were characterized through time variations in the infrasound wave amplitudes and frequency content in power spectral densities. We identified and characterized the infrasound signals that originate in the atmosphere, the solid Earth, and urban environments. The results show a highly saturated infrasound environment with diurnal and seasonal variations, indicating signals from anthropogenic and natural sources. Our results indicated that individual sources could be well differentiated. We identified infrasound signals produced by earthquakes, rainstorms, and thunders, as well as 12 families of infrasound signals with unknown sources. Finally, this study demonstrates that new information can be acquired to characterize phenomena of interest by studying infrasound signals. Moreover, the characterization and analysis of this dataset add to the general knowledge of infrasound environments that, along with other studies worldwide, might provide insight into the application and use of infrasound signals.