Revisiting Angular Velocity Plate Models for South America

In the last decades, many angular velocity models have been produced based on geological/geophysical and/or geodetic measurements. The first ones (e.g., NUVEL-1A and MORVEL) average the motions of tectonic models in the last 3My whereas the geodetic ones (e.g., REVEL and GEODVEL) are representative of the present-day tectonic motions. Plate angular velocities models are necessary to analyse inter- and intra-deformations due to the secular motions of tectonic plates. They permit quantify the magnitude and direction of relative displacement between different tectonic units. The use of inaccurate models can produce incorrect conclusions, particularly at plate boundaries. In this work, we discuss the differences of both approaches by looking at the South America tectonic plate, which is the slowest one of the large tectonic plates. We compare our own dedicated estimations of the plate angular velocities for these plates with the predicted motions given by global plate models and other recent published models. We show that the differences can still be significant when different plate models are considered despite of the small magnitude of the South America, which can lead to incorrect interpretations, particularly on the deforming boundaries like in Colombia. We also evaluate the influence of recent major earthquakes along the Andean Cordillera region since 2010 in the estimation of the geodetic velocity fields, and consequently on the angular velocity models. This study uses computational resources provided by C4G Collaboratory for Geosciences (PINFRA/22151/2016). It is also supported by project FCT/UIDB/50019/2020 IDL funded by FCT.