This study determines a one-dimensional seismic velocity model to be used in the daily routine analysis of earthquake data. This is useful for the geographical localization of the seismic events as well as an initial model for 3D seismic tomography studies. In order to calculate the velocity model, the Cuban earthquake catalogue from 1998 until the 2004 was used. The chosen area for the study is located in the eastern part of the Cuban Island, specifically between 19.80-21.00 north latitude and 74.33-77.00 west longitude. From a total of 209 local events, 117 events with RMS between 0 and 1 seconds, GAP between 0-180° and recorded for 3 or more stations were selected. The obtained velocity model has mainly three layers. A shallow layer 1 km-thick and P-wave velocity of 3.6 km/s, an intermediate layer 6 km-thick and P-wave velocity of 5.8 km/s and a bottom layer 13 km-thick and P-wave velocity of 6.9 km/s. The results suggest a transitional crust with an average thickness of 20 km.

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.