Subtopic 3.1 "The drivers of Geohazards"
The research in this Subtopic involves a multidisciplinary analysis of the physical, chemical and rheological properties of the Earth, and its current and past states with respect to its geodynamic setting. Subtopic 3.1 explores the multi-scale coupling of the various Solid Earth system processes and their interactions with the surface and surrounding space. This involves studies such as linking core/mantle convection with lithospheric deformation and crustal processes, including their observable expressions in the surface geology (orogeny, basin formation, faulting, magmatism, uplift, and erosion) and beyond (the geomagnetic field). The key challenge faced is the enormous spread of the spatial and temporal scales involved, ranging from seconds to millions of years and from millimeters to thousands of kilometers.
Four key themes are central to this Subtopic:
Material properties: Novel analytical, experimental and modeling techniques are employed to elucidate the chemical, mechanical and thermal properties of crustal and mantle minerals and rocks. Examples include mineral phase transitions that can drive deep earthquakes, the genesis of geofluids by melting or devolatilization reactions, the variability of fault and material properties at subduction megathrusts and the erodibility of exposed rocks.
Structures, fluids, magmas and magnetic/gravity fields: In order to image the present-day state of the Earth’s crust, mantle, and core, dedicated geochemical, seismological, gravity, and electromagnetic surveys using land-, ocean-, and air-based sampling and observatory networks are undertaken at focus sites (Chile, Turkey, Mt. Etna, Iceland, Eifel) and other key locations. Permanent global networks of seismic and geomagnetic stations contribute to global monitoring as well as satellite-based monitoring of the Earth’s gravity and magnetic fields.
Temporal Evolution: The short- (human time scale) and long-term (geological scale) evolution of Earth’s internal structures, processes, and their surface expressions are inferred. This involves geophysical experiments, geochemical and mineralogical analysis of geological archives, mapping of past and present deformation patterns and resolving the current and past stress states of the Earth’s crust. Changes in the Earth’s magnetic field are monitored to gain information on deep-earth processes.
Processes: Observational, analytical, and experimental studies are combined with cross-scale modeling and data integration to understand the complex links between material properties, geological structures, geofluids, and their temporal evolution . A variety of modeling tools is developed and improved including; mantle and core convection simulations, cross-scale lithosphere deformation and surface processes, atomistic numerical and elasto-gravitational wave simulations, and space weather models.