Geodetic Monitoring of the Variable Surface Deformation in Latin America

Abstract

Based on 24 years of high-level GNSS data analysis, we present a sequence of crustal deformation models showing the varying surface kinematics in Latin America. The deformation models are inferred from GNSS station horizontal velocities using a leastsquares collocation approach with empirically determined covariance functions. The main innovation of this study is the assumption of continuous surface deformation. We do not introduce rigid microplates, blocks or slivers which enforce constraints on the deformation model. Our results show that the only stable areas in Latin America are the Guiana, Brazilian and Atlantic shields; the other tectonic entities, like the Caribbean plate and the North Andes, Panama and Altiplano blocks are deforming. The present surface deformation is highly influenced by the effects of seven major earthquakes:

Combination Strategy for the Geocentric Realization of Regional Epoch Reference Frames

“… Changes in the Latin American reference frame kinematics induced by strong earthquakes. They are inferred from the difference between the two latest multi‐year solutions SIR15P01 (Sánchez & Drewes, 2016) and SIR17P01 (Sánchez & Drewes, 2020). Blue stars represent earthquakes with Mw > 6.0 since January 1, 2010.…”

“…The disadvantage of the alignment to linearly parametrized reference coordinates is that neither seasonal variations, for example, caused by atmospheric, oceanic, and hydrological loading (Seitz & Krügel, 2009; F. Seitz et al., 2014; Glomsda, Bloßfeld, et al., 2021), nor anthropogenic changes such as subsidence due to groundwater withdrawal (e.g., Bevis et al., 2005), are fully modeled in the reference coordinates. Moreover, especially in the extrapolation period of a reference frame, episodic changes like seismic events (Sánchez & Drewes, 2016, 2020) are no longer represented in the reference coordinates. The accuracy of the geocentricity of the resulting coordinates thus decreases over time, meaning that the coordinates' information value for research of geodynamics or global change decreases substantially.…”

Analysis of local surface displacement using repeated GPS measurements: a case study of the Guabirotuba area, Curitiba, Brazil

“…IMBT, NEIA, POLI, PRGU, PRMA, SCAQ, SCFL, SCLA, SPBO and SPPI stations). These are all part of the latest SIRGAS multi-year solution (i.e., SIR17P01), which is aligned to the IGS14 reference frame, epoch 2015.0 (Sánchez and Drewes 2020). The stabilization process of the individual solutions was performed by using generalized constraints.…”

“…First of all, and in order to evaluate the consistency of our velocities with reference to SIRGAS velocities, a direct comparison was performed between them and those obtained in the latest SIRGAS solution (i.e. SIR17P01) (Sánchez and Drewes 2020). Figure 6 and Tables 2, show the velocities and their absolute differences obtained for each of the 10 SIRGAS-CON stations used in the stabilization process and the UFPR station, which is also part of the SIR17P01 solution.…”

“…The ability of Global Navigation Satellite Systems (GNSS) to estimate high accuracy 3D positions has contributed greatly to the development of new monitoring techniques aimed at understanding how different tectonic and geological processes affect the Earth surface and fundamentally, to explain how these mechanisms impact the society and the environment (Bock and Melgar 2016). One of the main applications that currently make use of GNSS is the study and monitoring of geophysical phenomena (e.g., tectonic motion, fault zones, landslides, subduction processes, and volcanoes) (Luna et al 2017, Duman and Sanli 2019, Sánchez and Drewes 2020. In this scenario, GNSS observations play an important role, since they provide estimates of crustal deformation with respect to a global terrestrial reference frame, while also provide constraints of the nature of the forces acting on the Earth surface (Lambeck 1988).…”