Study of the mountain front of the Pinar Fault Zone, western Cuba, and its relation with recent tectonics

Abstract

The Pinar fault zone is a large tectonic dislocation of long and complex kinematic history, which is located in western Cuba, southward of the Guaniguanico Mountain Range. Its study has a great importance given its seismogenic nature. In the research, tectonic geomorphology tools were applied to evaluate the active deformations associated with this structure. The processing of the digital elevation model with 25 m of spatial resolution allowed to extract the synthetic drainage network and its hydrographic sub-basins, delimit the mountain front and quantify the geometric parameters of its triangular facets. The empirical models of Tsimi and Ganas (2015) and De Polo and Anderson (2000) were applied to estimate the vertical lifting rates along the mountain front, from the slopes and heights of the facets. As the activity of the fault is reflected in the drainage basins with which it is in contact, they were studied using geomorphic indices such as asymmetry factor (AF), hypsometric integral (HI), internal relief (DV), and density of the gradient rupture points, among others. The study showed that the front in the eastern part is characterized by presenting well-defined facets, which are higher and steeper. The variations of geomorphic indices of the front and of the drainage sub-basins along the path of fault reflect changes in its recent tectonic activity, and allowed to divide the fault zone into three geomorphic segments, that correspond to morph structural blocks. Finally, it was possible to establish that the vertical lifting rate fluctuates between 0.04-0.71 mm / year, reaching the maximum values to the NE segment of the fault, where it manifests its highest seismogenic potential.