TERPRO International Focus Groups & Projects

We all live on a planetary surface shaped by terrestrial geoprocesses. This topic has been much in the news lately due to the increase in extreme meteorological events, attributed by some to global climate change. But crustal volcanism and active tectonics also influence terrestrial geoprocesses. These crustal processes make the news only when a large earthquake or eruption occurs, but the events soon drop from the news and people forget about them. However, their secondary effects on terrestrial geoprocesses continue. Our proposed IFG “Terrestrial Processes Perturbed by Tectonics” (TPPT) will support studies of the longer-term effects of tectonic events on geomorphic systems, and contrast them with effects of non-seismic forcing such as extreme meteorological events and slower climate change.

Studies of this type are best described as ‘tectonic geomorphology’, but most past tectonic geomorphology studies have been descriptive rather than process-oriented. From a process perspective, an earthquake induces a rapid perturbation to a steady-state geomorphic system, which then triggers a system response. The response can be characterized spatially (severity over a geographic extent) or temporally. The response also, via erosion/deposition, creates an archive in the Holocene geologic record, just as climate changes have done. Specifically, we propose to address two broad questions: (1) how a geomorphic system’s long-term response to earthquakes differs from its response to (say) extreme meteorological events, or from slower climate change, and (2) whether the indicators of secondary tectonic effects in the geologic record have unique characteristics, that would allow them the be distinguished from non-tectonic causes. This effort builds on past TERPRO work on the immediate secondary effects of large earthquakes (e.g. the ESI Scale), but extends it back into the late Quaternary. Comparing tectonic ‘archive’ data to its climate archive counterparts will involve participation from the broad disciplinary range within TERPRO.

Leaders: Stéphane Baize (France), Gabriel Gonzalez (Chile), Xuanmei Fan (China)

Website: http://www.earthquakegeology.com/

Contact: Stephane.baize@irsn.fr

This IFG focuses on continental environments, where the Quaternary evolution has been mainly driven by depositional and erosive phases, varying in time and space, and alternating with less dynamic periods, allowing for soil formation. The associated dynamic processes are recorded in various kinds of geomorphic landforms and deposits, e.g., fluvial, lacustrine, colluvial and eolian sediments, as well as erosional discontinuities. Previous topographic surfaces may get removed, buried or dismantled. On the other hand, the periods of relative geomorphological stability are documented by fossil soils (palaeosols). Their erosion or burial marks the onset of another dynamic phase. The complexity of these geomorphological-sedimentological-palaeopedological archives is further increased, as the associated hydrological, pedological and aeolian processes are not independent from each other: Surface processes related to the hydrological cycle are among the main forces shaping a landscape. The available moisture is also a major factor in the formation of soils and their characteristics, and it is of paramount importance in controlling the production of dust. Dust in the atmosphere in turn plays an important role in climate dynamics.

In the present situation, with rapid climate change, a profound understanding of how surface processes work, how they interact, and how they respond to climatic variations, is of utmost importance. Thus, a comprehension of the earth surface dynamics and its drivers over the Quaternary is a key issue of this IFG. Thereby, our goals are (1) to stimulate progress in each of the involved disciplines, i.e. palaeohydrology, aeolian dust research and palaeopedology, and (2) to bring these disciplines together, e.g. at interdisciplinary conference sessions and workshops to promote the interdisciplinary interpretation of complex continental archives. The IFG has a global perspective but also considers regional and local scales, where representative case studies are carried out and ground truth can be obtained. The time frame of interest encompasses the whole Quaternary up to recent times, with a multidisciplinary approach that includes remote sensing, field work, laboratory analyses, numerical modelling and simulations.

The planned meeting of FLAG in Moscow in September 2020 has been cancelled due to Coronavirus and re-scheduled for September 2021.

Leaders: Alessandro Fontana (Italy), Daniela Sauer (Germany), Onn Crouvi (Israel), Rajiv Sinha (India).

Website:

Contact: alessandro.fontana@unipd.it