Horizontal and vertical deformation rates linked to the Magallanes- Fagnano Fault System, Tierra del Fuego: interpretation of the geodetic observations in the context of geological evidence and the current seismic cycle

L. MENDOZA; A. RICHTER; E. MARDERWALD; J. L. HORMAECHEA; G. CONNON; M. SCHEINERT; R. DIETRICH; R. PERDOMO

Beijing

Congreso; Scientific Assembly of the International Association of Geodesy; 2021

International Association of Geodesy

We present results which are based on 24 years of GNSS observations at Tierra del Fuego, since 1994. The data analysis is based on a reprocessing of all data with up-to-date models and satellite products. We apply a precise point positioning (PPP) processing strategy, made possible by the recent availability of highly accurate and consistent GNSS satellite orbits and clocks. The 54 stations included in the analysis allow a detailed investigation of horizontal and vertical velocity rates which provide a sound basis to study the deformation associated with the Magellanes-Fagnano Fault System, i. e. the transform boundary between the South American and Scotia plates at the southern tip of Patagonia. A deeper geophysical modelling has been performed which points to a seismogenic layer thickness of 15 ± 3 km and to fault planes inclined 64 ± 4 deg at the uppermost ends of the fault segments. Furthermore, we model the current seismic cycle from the great 1949 M w 7.7 earthquake to the present, including the ongoing postseismic viscoelastic relaxation process. We identify a seismic moment deficit rate and a cumulative seismic moment which is at present equivalent to an earthquake of magnitude Mw ~ 7.