More than 18,000 geoscientists from 136 countries met from April 19-30 for the virtual EGU General Assembly 2021, covering all disciplines of Earth, planetary and space sciences. Researchers from LIAG introduced participants to applied geophysics and its methods and applications in numerous sessions. Topics included: The potential of shallow shear wave and multicomponent seismic imaging, imaging salt structures in northern Germany, 3-D seismic for studies of glacier tectonic structures, characterization of geothermal reservoirs, climate responses to orbital forces, advances in reconstructing Earth system and human dynamics, or the open-source custEM 1.0 3-D finite element modeling toolbox of electromagnetic data.
Sessions organized by LIAG scientists:
Shallow shear-wave and multi-component seismic techniques – methodical capability, technical developments, data processing, and case studies
In recent years, the application of shear-wave seismic methods for shallow investigations (< 500 m depth) has become more and more popular. Shear waves are utilized for structural imaging, geotechnical investigations, and elastic parameter analysis. Methods using shear waves comprise, e.g., reflection imaging, tomography, and full waveform inversion.
Shear-wave imaging has great potential for shallow studies. For instance, near-surface resolution profits from low shear-wave velocities. Especially, shear wave reflection signals can be detected at small offsets compared to P-waves, which makes shear-wave reflection surveying cost efficient. Shear-wave surveys can profit from sealed ground conditions due to the suppression of Lovewaves, and, thus, are predesignated for urban areas. But shallow shear-wave and multicomponent seismic requires a continuous technical development of specialized sources and customized equipment and makes innovative concepts for acquisition and data processing necessary (e.g. interferometry, full waveform inversion, converted waves).
Exciting as well as recording several components of the ground motion simultaneously is further beneficial, since it allows separating vertically (SV) and horizontally (SH) polarized shear wavefields, which is mandatory for 3-D surveys. Wave conversion and scattering effects can be distinguished, and differently polarised shear waves simplify the detection of seismic anisotropy. This session promotes the exchange of experience using shear waves in shallow applications and triggers discussions about their potential in seismic imaging. Combined studies using P- and shear waves are a plus. With the focus on shear waves, we invite, but do not restrict, contributions to technical development, data analysis, seismic processing, and case studies. The latter may comprise, e.g., (a) geotechnical studies, such as examination of soil rigidity, (b) exploration of structures, such as volcanic craters or groundwater resources, (c) analysis of neotectonics, active faults, quick clays, landslides, sinkholes, and subrosion structures, and (d) more exotic applications, such as the exploration of glacier ice thickness.
Convener: Sonja Wadas | Co-conveners: Thomas Burschil, Barbara Dietiker, Pier Vittorio Radogna
Link to session: https://meetingorganizer.copernicus.org/EGU21/session/39303
Climate response to orbital forcing
The pacing of the global climate system by orbital variations is clearly demonstrated in the timing of e.g. glacial-interglacial cycles. The mechanisms that translate this forcing into geoarchives and climate changes continue to be debated. We invite submissions that explore the climate system response to orbital forcing, and that test the stability of these relationships under different climate regimes or across evolving climate states (e.g. mid Pleistocene transition, Pliocene-Pleistocene transition, Miocene vs Pliocene, and also older climate transitions). Submissions exploring proxy data and/or modelling work are welcomed, as this session aims to bring together proxy-based, theoretical and/or modelling studies focused on global and regional climate responses to astronomical forcing at different time scales in the Phanerozoic.
Convener: Stefanie Kaboth-Bahr | Co-conveners: Anne-Christine Da Silva, Mingsong Li, Huanchun Wu, Christian Zeeden
Link to session: https://meetingorganizer.copernicus.org/EGU21/session/40698
Integrated Stratigraphy - Recent advances in reconstructing Earth System and human dynamics
Earth history is punctuated by major extinction and dispersal events, by perturbations of global biogeochemical cycles and by rapid climate shifts. Such Earth System dynamics are relevant both on geologic (10^4-10 year) and human (10^2 - 10^4 year) timescales. Investigations of slow evolutions and fast events in Earth history are based on accurate and integrated stratigraphy. This, in turn, enables the interpretation of a wide variety of geoarchives, documenting the evolution of our planet and its inhabitants. This session will bring together specialists in litho-, bio-, chemo-, magneto-, cyclo-, sequence-, and chronostratigraphy with paleontologists, paleoclimatologists, paleoceanographers and archaelogists. An emphasis is placed upon the use of a variety of tools for deciphering sedimentary records and their stratigraphy across intervals of major environmental change and/or human evolution. This session is organized by the International Subcommission on Stratigraphic Classification (ISSC) of the International Commission on Stratigraphy (ICS) and it is open to the Earth science community at large.
Convener: David De Vleeschouwer | Co-conveners: Frederik Hilgen, Werner Piller, Tiffany Rivera, Christian Zeeden, Janina J. (Bösken) Nett
Link to session: https://meetingorganizer.copernicus.org/EGU21/session/39689
Accretional soil formation in northern hemisphere loess regions - evidence from OSL-dating of the P/H climatic transition from China, Europe and North America
Daniela Constantin, Joseph Mason, Ulrich Hambach, Daniel Veres, Cristian Panaiotu, Christian Zeeden, Liping Zhou, Slobodan Marković, Natalia Gerasimenko, Anca Avram, Viorica Tecsa, Stefana Madalina Sacaciu-Groza, Laura del Valle Villalonga, Robert Begy, and Alida Timar-Gabor
3D Finite-Element Modeling of Electromagnetic Data with the Open-Source Toolbox custEM 1.0
Raphael Rochlitz and Thomas Guenther
Characterisation of a highly heterogeneous geothermal reservoir based on geophysical well logs
Johanna Bauer, Daniela Pfrang, and Michael Krumbholz
Decoding geochemical signals of the Schwalbenberg Loess-Palaeosol-Sequences — A key to Upper Pleistocene terrestrial ecosystem responses in western Central Europe
Mathias Vinnepand, Peter Fischer, Christian Zeeden, Philipp Schulte, Sabine Fiedler, Olaf Jöris, Ulrich Hambach, Kathryn Fitzsimmons, Charlotte Prud'homme, Zoran Péric, Wolfgang Schirmer, Frank Lehmkuhl, and Andreas Vött
Half-precession signals in Lake Ohrid and their spatial and temporal connection to proxy records in the European realm
Arne Ulfers, Christian Zeeden, Silke Voigt, and Thomas Wonik
Insolation-paced sea level during the Early Pleistocene, Taiwan
Romain Vaucher, Shahin E. Dashtgard, Chorng-Shern Horng, Christian Zeeden, Antoine Dillinger, Yu-Yen Pan, Romy Ari Setiaji, Wen-Rong Chi, and Ludvig Löwemark
Long-term monitoring of coastal saltwater intrusion using the geoelectrical monitoring system SAMOS
Michael Grinat, Mathias Ronczka, Thomas Günther, Dieter Epping, Vitali Kipke, and Mike Mueller-Petke
Millennial-timescale reconstruction of Upper Pleistocene temperature and precipitation derived from earthworm calcite granules in western European loess profiles
Charlotte Prud'homme, Peter Fischer, Olaf Jöris, Christine Hatté, Mathias Vinnepand, Hubert Vonhof, Olivier Moine, Andreas Vött, and Kathryn Fitzsimmons
Near-surface glaciotectonic structures in the sediments of an overdeepened glacial valley revealed by a shallow 3D seismic survey
David Tanner, Hermann Buness, and Thomas Burschil
Reflection seismic imaging of buried shallow salt structures – examples from ongoing case studies in Northern Germany
Ulrich Polom, Rebekka Mecking, Phillip Leineweber, and Andreas Omlin
Relationships between meteorological data and soil properties: quantifying precipitation and aridity in the Middle Danube Basin through geophysical proxies
Christian Zeeden, Mathias Vinnepand, Kamila Ryzner, Christian Rolf, Christian Laag, Mehrdad Sardar Abadi, Milica G. Radaković, Milivoj B. Gavrilov, and Slobodan B. Marković
Stratigraphy and chronology of Late Pleistocene loess-paleosol sequence of the East European Plain and correlation with Late Pleistocene archives of Europe
Svetlana Sycheva, Manfred Frechen, Birgit Terhorst, Sergey Sedov, and Olga Khokhlova
The shape and infill of the Basadingen overdeepened glacial valley from P-wave seismic reflections
Anna-Catharina Brandt, David C. Tanner, Hermann Buness, Thomas Burschil, and Gerald Gabriel
Using borehole gamma-ray spectroscopy to detect tephra layers in lacustrine deposits: An example from Lake Chalco, central Mexico
Mehrdad Sardar Abadi, Christian Zeeden, Arne Ulfers, Katja Hesse, and Thomas Wonik
Drilling Overdeepened Alpine Valleys (DOVE) – presentation on the progress of Tannwald research with video greeting from the drilling site
Flavio Anselmetti, Gerald Gabriel, and David C. Tanner