TY - JOUR A1 - Gholamrezaie, Ershad A1 - Scheck-Wenderoth, Magdalena A1 - Cacace, Mauro A1 - Bott, Judith A1 - Heidbach, Oliver A1 - Bohnhoff, Marco A1 - Strecker, Manfred R. T1 - Lithospheric strength variations and seismotectonic segmentation below the Sea of Marmara JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - The Sea of Marmara is a tectonically active basin that straddles the North Anatolian Fault Zone (NAFZ), a major strike-slip fault that separates the Eurasian and Anatolian tectonic plates. The Main Marmara Fault (MMF), which is part of the NAFZ, contains an approximately 150 km long seismotectonic segment that has not ruptured since 1766. A key question for seismic hazard and risk assessment is whether or not the next rupture along this segment is likely to produce one major earthquake or a series of smaller earthquakes. Geomechanical characteristics such as along-strike variations in rock strength may provide an important control on seismotectonic segmentation. We find that variations in lithospheric strength throughout the Marmara region control the mechanical segmentation of the MMF and help explain its long-term seismotectonic segmentation. In particular, a strong crust that is mechanically coupled to the upper mantle spatially correlates with aseismic patches, where the MMF bends and changes its strike in response to the presence of high-density lower crustal bodies. Between the bends, mechanically weaker crustal domains that are decoupled from the mantle indicate a predominance of creeping. These results are highly relevant for the ongoing debate regarding the characteristics of the Marmara seismic gap, especially in view of the seismic hazard (Mw > 7) in the densely populated Marmara region. KW - North Anatolian Fault Zone KW - Sea of Marmara KW - Seismic gap KW - Lithospheric KW - strength KW - Thermal modeling KW - Rheological modeling Y1 - 2021 U6 - https://doi.org/10.1016/j.tecto.2021.228999 SN - 0040-1951 SN - 1879-3266 VL - 815 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Dey, Saptarshi A1 - Bookhagen, Bodo A1 - Thiede, Rasmus C. A1 - Wittmann, Hella A1 - Chauhan, Naveen A1 - Jain, Vikrant A1 - Strecker, Manfred R. T1 - Impact of Late Pleistocene climate variability on paleo-erosion rates in the western Himalaya JF - Earth and planetary science letters N2 - It has been proposed that at short timescales of 10(2)-10(5) yr, climatic variability can explain variations in sediment flux, but in orogens with pronounced climatic gradients rate changes caused by the oscillating efficiency in rainfall, runoff, and/or sediment transport and deposition are still not well-constrained. To explore landscape responses under variable climatic forcing, we evaluate time windows of prevailing sediment aggradation and related paleo-erosion rates from the southern flanks of the Dhauladhar Range in the western Himalaya. We compare past and present Be-10-derived erosion rates of well-dated Late Pleistocene fluvial landforms and modern river sediments and reconstruct the sediment aggradation and incision history based on new luminescence data. Our results document significant variations in erosion rates ranging from 0.1 to 3.4 mm/yr over the Late Pleistocene. We find that, during times of weak monsoon intensity, the moderately steep areas (hillslope angles of 27 +/- 13 degrees) erode at lower rates of 0.1-0.4 mm/yr compared to steeper (>40 degrees) crestal regions of the Dhauladhar Range that erode at 0.8-1.3 mm/yr. In contrast, during several millennia of stronger monsoon intensity, both the moderately steep and high slope areas record higher erosion rates (>1-3.4 mm/yr). Lithological clast-count analysis shows that this increase of erosion is focused in the moderately steep areas, where Lesser Himalayan rocks are exposed. Our data thus highlight the highly non-linear response of climatic forcing on landscape evolution and suggest complex depositional processes and sedimentary signals in downstream areas. (C) 2021 Elsevier B.V. All rights reserved. KW - erosion KW - cosmogenic nuclides KW - luminescence dating KW - Indian summer monsoon KW - Himalaya Y1 - 2022 U6 - https://doi.org/10.1016/j.epsl.2021.117326 SN - 0012-821X SN - 1385-013X VL - 578 PB - Elsevier CY - Amsterdam [u.a.] ER -