Seismicity of the Lerma Valley (NW Argentina) and wavefield driven amplification phenomena

This thesis investigates the seismotectonic activity and crustal structure of the Argentine Eastern Cordillera of the Lerma Valley in the Central Andes through a multidisciplinary approach that combines seismic event analysis, structural imaging, and wave propagation modeling. The data set was retrieved by installing a seismic network with thirteen seismometers. First, a detailed study of microseismicity, including event localization, magnitude estimation, focal mechanisms, and stress inversion is used to provide a refined interpretation of active tectonic deformation zones. These results enhance previous models by linking seismogenic deformation to the dynamic behavior of structures in the middle and lower crust. Second, the characterization of crustal discontinuities is extended by integrating receiver function analysis with ambient noise cross-correlation tomography. The combination of the obtained datasets allows for the derivation of a velocity model at each seismic station of the investigated area, which is subsequently inverted to reveal the spatial variation of key structural boundaries in latitude and longitude. Third, a theoretical framework is developed to describe elastic cylindrical wave propagation in an embedded half-cylinder within a half-space of contrasting physical properties. The analytical solution, derived via Fourier series expansion of a delta-like potential, provides a closed-form expression for the Fourier coefficients and offers new insights into wavefront dynamics in complex geological settings. Together, these studies contribute to a deeper understanding of the seismotectonic processes and structural heterogeneity of the Eastern Cordillera and the adjacent Andean foreland, with implications for regional geodynamics and hazard assessment.