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Infrasound Observations at Bahía de Banderas, Western Mexico

Bulletin of the Seismological Society of America

Volume 113, Number 4
August 2023

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.

Seismic Structure of the Southern Rivera Plate and Jalisco Block Subduction Zone

Seismological Research Letters

Volume 90, Number 5
September/October 2019

Structural and tectonic features in the Pacific Coast of Mexico generate a high level of seismic activity in the Jalisco block (JB) region, making it one of the most attractive areas of the world for geophysical investigations. The Rivera–North America contact zone has been the object of different tectonic studies in recent years framed within the TsuJal project. To this day, this project is generating numerous crucial geophysical results, which significantly improve our understanding of the region. Our study is focused on the interaction between the south of the JB and Rivera plate (RP), which crosses the Middle America trench. We also cover anoffshore–onshore transect of 130 km length between the eastern Rivera fracture zone and La Huerta region, in the Jalisco state. To characterize this region,we interpretedwide-angle seismic, multichannel seismic, and multibeam bathymetry data. The integration of these results, with the local and regional seismicity recorded by the Jalisco Seismic Accelerometric Telemetric Network and by the Mapping the Rivera Subduction Zone experiment, provides new insights into the geometry of the southern RP, which is dipping12°–14° under the JB in the northeast–southwest direction. Moreover, our results provide new seismic images of the accretionary wedge, the shallow crust, the deep crust, and the upper-mantle structure along this profile.