Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

are considered more appropriate for quantifying the deformation associated with the propagation of thrusts. These surfaces have been used as finite strain markers in many active contractional settings (Avouac et al. 1993; Mueller and Suppe, 1997; Ishiyama et al. 2007; Gold et al. 2006; Le Béon et al. 2014; Costa et al., 2019, among others) While previous studies have explored neotectonics and seismic hazard in this region (Richard et al. 2019 Rimando et al. 2019; Rockwell et al., 2014, 2022) ourwork seeks tooffer newinsights and innovative perspectives on the analysis of Quaternary deformation. We propose three main approaches: a) characterization of the drainage system and assessment of its equilibrium state through regional- scale morphometric analyses; b) detailed mapping of alluvial terraces to understand the distribution of Quaternary deformation; and c) we intend to create a model of the structures affecting the Neogene and Quaternary levels by conducting a balanced cross- section, through which we aim to depict its evolution over time. In this work we present the preliminary results of a) and b). METHODOLOGY To assess Quaternary deformation, we employed various methodologies focused on topographic and geometric analyses. The study presented here corresponds to an analysis of drainage basin systems and morphologies of Quaternary alluvial terraces, carried out by processing a 5 meters/pixel-resolution digital elevation model obtained from aerophotogrametric surveys (National Geographic Institute IGN, Argentina from http:// www.ign.gob.ar). The different analyses were performed by implementing the functions of the TopoToolbox software in MatLab and Quantum GIS (QGIS). We studied the drainage systemand calculatedmorphometric indices such as the normalized steepness index (Ksn), analyzing river profiles and knickpoints to identify potential areas of tectonic activity. A detailed mapping of alluvial terraces was used to determine statistical parameters of these terraces (elevation and gradient) and to perform detailed topographic profiles. We extracted topographic profiles from all the terraces and normalized them to the elevation of the river in the correspondent sector. Moreover, we use a Python code to create Relative Elevation Models (REMs) or Height above river (HAR) rasters which are produced by detrending the baseline elevation to follow the water surface of the stream. R E F E R E N C E S Avouac, J-P., Tapponnier, P., Bai, M., You, H. y Wang, G. 1993. Active thrusting and folding along the Northern Tien Shan and Late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan. Journal of Geophysical Research, 98 (B4), 6755-6804, doi: 10.1029/92JB01963. Costa, C.H., Schoenbohm, L.M., Brooks, B.A., Gardini, C.E. y Richard, A.D., 2019. Assessing Quaternary shortening rates at an Andean frontal thrust (32 30′ S), Argentina. Tectonics, 38(8): 3034-3051. Gold, R., Cowgill, E. Wang, X, y Chen, X. 2006. Application of trishear fault-propagation folding to active reverse faults: examples from the Dalong Fault, Gansu Province, NW China, Journal of Structural Geology, 28, 200–219. DOI : 10.1016/j .jsg.2005.10.006 Hedrick, K., Owen, L., Rockwell, K., Meigs, A., Costa, C., Ahumada, E., Caffee, M. yMasana, E., 2013. Timing and nature of alluvial fan and strath terrace formation in the Eastern Precordillera of Argentina. Quaternary Science Reviews 80: 143-168. Ishiyama, T., Mueller, K. Sato, H. y Togo, M. 2007. Coseismic fault-related fold model, growth structure,and the historic multisegment blind thrust earthquake on the basement- involved Yoro thrust, central Japan. Journal of Geophysical Research, 112, B03S07, doi:10.1029/2006JB004377.