Measurement and modelling of regional deformations

The high precision of geodetic space techniques allows the accurate estimation of 3D station positions and their changes with time. The analysis of position time series derived from geodetic stations permits the identification and quantification of geophysical effects, which shall be appropriately modelled to increase the reliability of the reference frames. These estimates are also very useful to provide input data of high quality for studying the global change and for early warning of natural disasters. The monitoring with regional continuously operating GNSS networks is the most applied strategy for this purpose, since this technique delivers high-resolution measurements in time and in space with relative low costs. However, to exploit the maximum precision of this technique a high-quality data processing is necessary together with an adequate distribution of GNSS stations in the region of study and the corresponding operational infrastructure. In the frame of the CGE, monitoring GNSS networks in the Alpine region, Island, Mediterranean, and Latin America are routinely analysed with the main objective of modelling deformation zones existing between the rigid plates. This analysis allows also to identify and to understand effects caused by volcanism and seismic events.

: Deformation of the Alpine-Adrian-Aegean area with respect to the European plate (model derived from the ITRF2008 computations carried out at DGFI).

Monitoring crustal deformations in the Alpine Region

: Horizontal movements of the northern Alps relative to the Eurasia plate.

: Vertical movements of the northern Alps.

In the frame of the ALPS-GPS QUAKENET project, a component of the Alpine Space Programme of the European Community Initiative Programme (CIP) INTERREG IIIB, DGFI installed in 2005 five continuously operating GPS stations located along the northern Alps boundary (see bellow). The main objective of this project was to study crustal deformations in near real-time to improve natural disaster prevention in the Alpine region. During the two years the project was carried out, DGFI provided the observational data of its stations to be analyzed together with other 25 stations installed in the area. Description, main features, and results of the project are presented in the report “ALPS GPS Quakenet: Alpine Integrated GPS Network”, available at www.alps-gps.units.it.

DGFI routinely process its five stations in a small network, which includes three IGS05 reference stations, three IGS global stations, and two EUREF stations in order to detect local and regional deformations. Station coordinate time series and yearly cumulative solutions of this network are derived from loosely constrained daily solutions starting on October 9, 2005. The obtained station movements mainly reflect the Eurasia plate displacement. Until now, regional or local deformations have not been identified.

Selected publications

Drewes H., Heidbach O.: The 2009 Horizontal Velocity Field for South America and the Caribbean. In: Kenyon S., M.C. Pacino, U. Marti (Eds.), "Geodesy for Planet Earth", IAG Symposia, 136: 657-664, 2012

Sánchez L., Seemüller W., Drewes H., Mateo L., González G., da Silva, Pampillón J., Martinez W., Cioce V., Cisneros D., Cimbaro S.: Long-term stability of the SIRGAS Reference Frame and episodic station movements caused by the seismic activity in the SIRGAS region. Proceedings of the IAG Symposium REFAG2010, Springer (accepted), 2012

Sánchez L., Drewes H.: Wie sich die Alpen bewegen. Akademie Aktuell. Bayerische Akademie der Wissenschaften. Heft 3, Aufgabe 34: 71-72, 2010.