Normal vector analysis from GNSS-GPS data applied to Deception volcano surface deformation

• Published in: Geophysical Journal International
• Main Authors: Berrocoso, M., Prates, Gonçalo, Fernandez-Ros, A., Garcia, A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2012
• Subjects: South-shetland islands; Bransfield strait; Antarctic peninsula; Tectonics; Field; Antarctic; Antarctic Peninsula; Austral; Bransfield Strait; Deception Island; South Shetland Islands; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10400.1/11919; https://doi.org/10.1111/j.1365-246X.2012.05584.x

Surface deformation parameters and its use in volcano monitoring have evolved from classical geodetic procedures up to those based on Global Navigation Satellite Systems (GNSS), in particular the most widely used and known Global Positioning System (GPS), profiting from the automated data processing, positioning precision and rates, as well as the large storage capacity and low power consumption of its equipments. These features have enabled the permanent GNSSGPS data acquisition to ensure the continuous monitoring of geodetic benchmarks for the evaluation of surface deformation in active tectonic or volcanic areas. In Deception Island (Antarctica), a normal vector analysis is being used to give surface deformation based on three permanently observed GNSSGPS benchmarks. Due to data availability, both in the past and for near real-time use, all benchmarks used are inside the monitored volcanic area, although the reference is away from thermal springs and/or fumaroles, unlike the other two. The time variation of slope distances to the reference benchmark and of the magnitude and inclination of the normal vector to the triangle defined by the reference benchmark and any other two, provides the spatial deformation in the volcanic area covered. The normal vector variation in magnitude gives information on compression or expansion, here called spatial dilatometer, while the changes in inclination gives information on relative uplift or subsidence, here called spatial inclinometer. In geodesy, the triangle is a basic geometric unit and the areal strain is commonly applied in tectonics and volcanism. The normal vector analysis conjugates both, benefiting from the method's precision, simplicity and possibility to model the surface using several triangles. The proposed method was applied to GNSSGPS data collected every austral summer between 20012002 and 20092010 in Deception Island. The results evidence that Deception Island acts as a strain marker in the Bransfield Basin volcano-tectonic setting. Spanish Ministry of ...