Seismological footprint of an anomalous atmospheric activity registered in March 2021, in Baja California, Mexico

Abstract

On 11 March 2021, a quite short strong signal was recorded by seismic stations of the CICESE Seismic Network, which cannot be associated with any regional or global earthquake. At the CICESE Campus and all along the city of Ensenada, in Baja California, Mexico, people reported vibration of the windows and even a short strong rumbling. Fortunately, houses and buildings did not report any damage. Due to the interaction between the atmosphere and the shallow earth surface, this anomalous atmospheric activity produced a special seismological footprint, with frequencies between 1 and 10 Hz. In this manuscript, we report on the observations of a multiparameter dataset, including seismic data along with wind velocity, wind density, temperature, humidity, atmospheric pressure, and THSW index. The atmospheric perturbation wave was strong enough to be clearly recorded by seismic stations within an area of almost 80 km and to produce some changes in the recorded meteorological parameters. The results from an FK analysis show that the atmospheric activity occurred to the south of Ensenada City and travelled to the north, as shown in the seismic records. We discuss the characteristics of the seismic signals in the frequency domain and the relation to the changes in the atmospheric parameters that could be related to this anomalous atmospheric activity.