Project

Erosion; orogeny; geodynamics; seismology; modeling

Lead
Gebirgsbildungsprozesse der Alpen im plattentektonischen 4D-Raum-Zeit-KontextDie Alpen und ihr näheres Umfeld sind ein ideales natürliches Laboratorium zum Studium von früheren und heutigen Prozessen der Gebirgsbildung und gleichzeitig ist dies eines der dichtest besiedelten Gebiete von Europa mit signifikanter Erdbebenaktivität. Das Verständnis des komplexen Zusammenspiels von Prozessen und Strukturen beobachtbar an der Erdoberfläche bedingt das Verständnis der plattentektonischen Kräfte im Erdinnern, welche sich im Laufe der Entwicklung der Alpen langsam verändern.
Lay summary
Inhalt und Ziele   Basierend auf den Expertisen der beteiligten Forschungsgruppen zielen die vier Teilprojekte auf (1) die detailierte Erfassung der 3D Tiefenstruktur des Alpenraumes sowie der Strömungen im darunterliegenden Erdmantel bis in 670km Tiefe; (2) eine Synthese der geophysikalischen und geologischen Informationen zur Gebirgsbildung der Alpen in einem kinematischen 3D Modell, welches die zeitabhängige Massenbilanz von der Subduktion bis zur Erosion der Oberflächengesteine miteinbezieht; (3) die Erfassung und Modellierung der Entwicklung der Topographie der Alpen; (4) numerische geodynamische Modellierung der Evolution des Alpenraumes der letzten 35 Mio Jahre und deren Zusammenhänge mit der Seismizität.   Wissenschaftlicher und gesellschaftlicher Kontext   Das Projekt fördert unser fundamentales Verständnis der Gebirgsbildung und der damit verbundenen plattentekonischen Prozesse. Neben den bekannten gebirgsspezifischen natürlichen Gefahren wie Muhrgänge und Bergstürze ist auch die Erdbebengefährdung innerhalb und im Umfeld der Alpen charakteristisch und mit den gebirgsbildenden Prozessen eng verknüpft. Unser Projekt soll einen wichtigen Beitrag liefern zum besseren Verständnis der Erdbebengefährdung im Alpenraum.

Direct link to Lay Summary

Last update: 22.07.2014

Self-organised

Communication	Title	Media	Place	Year

Number	Title	Start	Funding scheme

This SINERGIA project “SWISS-AlpArray” concerns the Swiss contribution to the international AlpArray research initiative (see linked AlpArray Science Plan). It combines a significant contribution to the collaborative seismic field experiment of 600+ broad band stations operating for 2.5 years with a series of targeted research projects within the frame of AlpArray science program and grouped into four subprojects. In collaboration with the Swiss Seismological Service SED (see appended letter of support) we will install and operate 40 permanent and 40 temporary seismic stations and coordinate data management for 600+ seismic stations including data quality control.The Alps are an ideal natural laboratory for studying on-going and past orogenic processes resulting from various interactions of multiple plates in space and time. At the same time this is also an area of significant and complex seismic activity in a densely populated part of Europe. The Alpine area is a truly 4-dimensional (space-time) orogenic system whose present-day complexity is the result of major plate reorganizations after Europe-Adria/Africa collision during the last 35 Myr. An exceptional diversity of geodynamic processes related to the orogeny in general and to Alpine-Apennines orogenic belts, in particular, may be studied in a comparatively small region and of unprecedented wealth of information previously existing or newly made available due to AlpArray initiative. These processes include: (1) interactions between large scale Africa-Europe-plate convergence and gravitationally induced slab retreat; (2) independent displacements and rotations of micro-plates in an overall regime of slow Africa-European convergence; (3) deformation of the asthenosphere-lithosphere boundary and its relationship to the highly complex crustal structure; (4) processes of slab tearing; and (5) slab polarity reversals which are taking place between the Alps and the Dinarides as well as the Alps and the Apennines; (6) evolution of surface topography as combined result of crustal deformation by plate tectonic processes and exhumation and erosion linked to climate processes.Research objectives of subproject 1 are devoted to high-resolution seismic imaging of the crust (3D structure and fabric, combining wealth of existing mainly P-wave information with high-resolution ambient noise tomography for AlpArray station network), to mantle lithosphere (3D geometries and fabric) and asthenosphere (3D flow pattern) by high-resolution anisotropic teleseismic P-wave tomography and to combined earthquake source-tectonokinematic process-based seismotectonic modelling of circum-Po plain seismicity to complement standard evaluations of seismic hazard.The research objectives of subproject 2 are to synthesize a variety of geophysical and geological data from the Alps and Northern Apennines through a kinematic framework. We will develop a methodology to incorporate plate, microplate and slab motion as boundary conditions to drive a strain model that will balance crustal mass, isostatically balance it, and thereby predict topography. Topography will be used to predict erosion rates, which also contributes to the mass balance of the orogen. This model will be applied through two PhD projects to the Alps and Northern Apennines. The objectives of subproject 3 are to provide an erosion model for the whole Alps during the Pleistocene and Holocene epochs based on thermochronological and cosmogenic nuclide record. The inferred erosion model will then be interpreted using an ice sheet erosion model coupled with a large geodynamic model to explore the coupling between deep-Earth geodynamic processes and glacial erosion, and therefore investigate the respective role of tectonics and climate on setting erosion rates across the Alps during the last 2 Myr.Research tasks in subproject 4 concentrate at: (A) Geodynamic evolution of Alps-Apennines region in the last 35 Myr. This will include 4D high-resolution modelling of entire Alps-Apennines system and address slab roll back dynamics and their relations to long-term asthenospheric flows and lithospheric and crustal shortening and extension processes. Visco-elasto-brittle/plastic (surficial)-thermo-mechanical approach will be employed. (B) Modern state, dynamics and seismicity of the Alpine lithosphere-mantle system. This will include numerical modelling of the present day stress state, crustal deformation, surface evolution, lithospheric and asthenospheric dynamics and seismicity regimes within the Alps-Apennine region. Visco-elasto-brittle/plastic seismo-thermo-mechanical approach will be employed.