The detection level of a seismic network is a measure of its effective ability to record small earthquakes in a given area. It can vary in both space and time and depends on several factors such as meteorological conditions, anthropic noise, local soil conditions—all factors that affect the seismic noise level—as well as the quality and operating condition of the instruments. The ability to estimate the level of detection is of tremendous importance both in the design of a new network and in determining whether a given network can recognize seismicity consistently or needs to be improved in some of its parts. In this article, we determine the detection level of the Cuban seismic network using the empirically estimated seismic noise spectral level at each station site and some theoretical relationships to predict the signal amplitude of a seismic event at individual stations. The minimum local detectable magnitude thus depends on some network parameters such as the signal-to-noise ratio and the number of stations used in the calculation. We also demonstrate the effectiveness of our predictions by comparing the estimated detection level with those empirically determined from one year of data (i.e., the year 2020) of the Cuban seismic catalog. Our analysis shows, on the one hand, in which areas the current Cuban network should be improved, also depending on the regional pattern of faults, and, on the other hand, indicates the magnitude threshold that can be assumed homogeneously for the catalog of Cuban earthquakes in 2020. Because the adopted method can use current measurements of the seismic noise level (e.g., daily), the proposed analysis can also be configured for continuous monitoring of network state quality.

This paper analyses seismic noise from broadband seismic stations within the Cuban National Seismic Service, focusing on location sites, soil or rock quality at installation sites and the impact of various factors on the noise signature of these seismic stations. A brief technical description of deployed equipment is provided and the methodology for data selection and analysis is presented.The study provides annual performance assessment for each station, considering  specific details for each particular case. Likewise, the effect of diurnal/nocturnal and seasonal variations on noise power spectral density (PSD) is analyzed. In addition, plotted graphs show the relationship between the occurrence of extreme weather events, such as hurricanes and cold fronts through Cuban eastern and western regions, respectively, and the increase of noise level, specifically for marine microseisms period band. Finally, the influence of instrumental variations in noise level of seismic stations is characterized.