Calculation and analysis of the focal mechanisms of the Bucaramanga Seismic Nest from records of the National Seismological Network
DOI:
https://doi.org/10.24054/bistua.v20i1.1159Keywords:
Focal mechanism, Fault plane, P waveAbstract
In the present document, the focal mechanisms of 32 earthquakes with magnitude Ml>4 in the Santander region known as the Seismic Nest of Bucaramanga, for the period 2008-2018, were analyzed. The solutions of the focal mechanisms are determined using the polarity method by analyzing the first arrival of the P wave at different seismic stations located around the region of interest, found between -74° up to -72° latitude, and between 6.7° to 6.9° longitude. The waveform data was obtained from the catalog of the National Seismological Network of Colombia (RNSC), considering the fact that most earthquakes occur in a depth range that goes from 140 km to 160 km. With the results obtained, a volume of 902 Km³ located under the Mesa de los Santos is estimated, this volume would represent an important part of the Nest, due to its high seismic concentration. The solutions of the focal mechanisms obtained do not allow establishing a direct and clear connection in relation to the subduction processes that occur between Caribbean-South American and Nazca South American tectonic plates.
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