The 1990-2017 Deception Volcano's geodynamic mechanism from GNSS data (Antarctic Peninsula)

Resumen

The GNSS observations in Deception Island have started along the 1988 austral summer. The REGID network established in 1990 initially constituted by 4 geodetic benchmarks allow the determination of the first ground-deformation models of the geodynamic behavior both volcanic and tectonic of the Island. During the period 1990-2017 the network has experienced a large transformation considering the number of benchmarks, semi-permanent stations, data link by WIFI, and multi-constellation registry (GPS, GLONASS and GALILEO). Today the REGID network has 16 geodetic bench marks around Port Foster and anadditional semi-permanent reference station in Livingston Island. During the austral summer, 3 benchmarks in Deception are also semipermanent stations. Ground-displacement time series analysis depict the combined influence of the South Shetland Islands central block tectonic regime, thus from the extensión present in the Bransfield basin rift and from the slow subduction of the former Pheonix micro-plate under the Antarctic plate. The 1998 1999 austral summer volcano reactivation was the most significant of this period. The ground-deformation and ground-displacement velocities are compatible with an accentuated process of extension and uplift. From 2001-2002 benchmarks are added to the REGID while 3 become semi-permanent stations that constitute the volcanic surveillance system based on ground-deformation with near real-time data link and data processing and analysis. In 2016-2017 this system was active. Several extension-uplift, compression-subsidence and transition periods have been observed. The extensión-uplift periods correlation with higher seismicity and the higher volcanic activity precursory signal of ground-deformation have been applied to establish volcanic processes forecasts. Therefore, the ground-displacement velocities and related ground-deformation models, and the location and evolution of point source models are presented. From them the geodynamic mechanism and evolution of Deception’s volcanism is discussed.