A regional model to estimate the seasonal vertical crustal deformation in South America based on GRACE and GPS long-term series.

GALVAN, R.; GENDE, M.; BRUNINI, C.

Postdam

Congreso; Association of Geodesy Scientific Assembly; 2013

International Association of Geodesy

Surface mass transfer produces changes in the terrestrial geometric reference frame clearly detectable by GNSS techniques. These deformations are mainly observed in the vertical coordinate component and have a periodic behavior with seasonal cycles. Therefore, the assumption that kinematic of the reference frame has a linear behavior is no longer sufficient. This study focuses on a model of crustal vertical deformations caused by surface loading variation in the South American region. Sixty-two locations were analyzed in order to adjust a parametric exponential function that relates height changes with mass pressure variations. This parametric function depends on regional rheological properties. Crustal deformation were characterized using multiannual GPS time series provided by SIRGAS and surface loading information was derived from GRACE spherical harmonics coefficients provided by GRGS (Release 2). The proposed parametric model was able to represent 65% of the total vertical displacement in nine-years (2004?2012) time-span analyzed that better fits than a simple harmonic representation. This study will contribute to have a better knowledge of the kinematics of the reference frame and an improved comprehension of the elastic parameters on a regional scale.