GD3.7/G3.2/TS9.9Integrating geodetic and geological studies of active crustal deformation (co-organized)
|Convener: M. Westerhaus | Co-Conveners: A. Demoulin , W. Shen
Kinematics is one major component in the general understanding of tectonic processes and in the particular study of earthquake geology. Such a wide research field obviously requires considering the rates of crustal motion at time scales ranging from the long term to the very short term and spatial scales from continental to local, and implies thus collecting and integrating data of different types. Long-term data are typically derived from the analysis of geological and geomorphological markers, while short-term data are provided by space-based and terrestrial geodetic measurements of ground displacements. In between, paleoseismology also yields fault motion estimates, whose comparison with geodetic data allows a discussion of seismic versus creeping behavior of faults. Beyond the remarkable consistency demonstrated since 25 years between geodetic and geological estimates of large-scale plate motions, there are a lot of settings where significant discrepancies between both types of data are still not resolved. This is especially true at the smaller scale of individual active structures and in intraplate environments, where a greater temporal variability of the tectonic activity may be expected and/or strain rates are small. There, separating the effects of this variability from other causes of discrepancy, notably measurement errors and ground motions of environmental and anthropogenic origin, remains a highly challenging task. How much are geological and geomorphological estimates of crustal and fault motion averaging variable deformation and slip rates? What are the characteristic time scales of relevant tectonic and non-tectonic mechanisms? How much are geodetic rates influenced by short term meteorological signals and/or long term climatic changes, and how can we separate these signals from the effects of tectonic stresses? Are estimates of vertical and horizontal displacement rates facing such difficulties equally? What are the intrinsic limitations of specific methods, and how can we assess their reliabilities? How can we proceed towards a rigorous combination of different data sets - via mathematical models or via inversion schemes based on geological/geophysical models?
This session aims to bring together geodesists, geologists and geomorphologists in order to compare and combine their data sets of tectonic deformation in various interplate and intraplate settings, to pinpoint the tectonic environments most prone to problems of data inconsistency, and to examine the reasons of diverging geodetic and geological rate estimates if they exist. It especially welcomes contributions that discuss data fusion approaches in order to derive improved 3D surface displacement fields as well as models integrating geodetic and geological data.