TY - JOUR A1 - Scherler, Dirk A1 - Schwanghart, Wolfgang T1 - Drainage divide networks BT - Part 2: Response to perturbations JF - Earth surface dynamics N2 - Drainage divides are organized into tree-like networks that may record information about drainage divide mobility. However, views diverge about how to best assess divide mobility. Here, we apply a new approach of automatically extracting and ordering drainage divide networks from digital elevation models to results from landscape evolution model experiments. We compared landscapes perturbed by strike-slip faulting and spatiotemporal variations in erodibility to a reference model to assess which topographic metrics (hillslope relief, flow distance, and chi) are diagnostic of divide mobility. Results show that divide segments that are a minimum distance of similar to 5 km from river confluences strive to attain constant values of hillslope relief and flow distance to the nearest stream. Disruptions of such patterns can be related to mobile divides that are lower than stable divides, closer to streams, and often asymmetric in shape. In general, we observe that drainage divides high up in the network, i.e., at great distances from river confluences, are more susceptible to disruptions than divides closer to these confluences and are thus more likely to record disturbance for a longer time period. We found that across-divide differences in hillslope relief proved more useful for assessing divide migration than other tested metrics. However, even stable drainage divide networks exhibit across-divide differences in any of the studied topographic metrics. Finally, we propose a new metric to quantify the connectivity of divide junctions. KW - dynamics KW - landscape evolution KW - low-relief KW - patterns KW - river KW - scale KW - tectonics Y1 - 2020 U6 - https://doi.org/10.5194/esurf-8-261-2020 SN - 2196-6311 SN - 2196-632X VL - 8 IS - 2 SP - 261 EP - 274 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Morishita, Yu A1 - Lazecky, Milan A1 - Wright, Tim J. A1 - Weiss, Jonathan R. A1 - Elliott, John R. A1 - Hooper, Andy T1 - LiCSBAS BT - an open-source InSAR time series analysis package integrated with the LiCSAR automated Sentinel-1 InSAR processor JF - Remote sensing N2 - For the past five years, the 2-satellite Sentinel-1 constellation has provided abundant and useful Synthetic Aperture Radar (SAR) data, which have the potential to reveal global ground surface deformation at high spatial and temporal resolutions. However, for most users, fully exploiting the large amount of associated data is challenging, especially over wide areas. To help address this challenge, we have developed LiCSBAS, an open-source SAR interferometry (InSAR) time series analysis package that integrates with the automated Sentinel-1 InSAR processor (LiCSAR). LiCSBAS utilizes freely available LiCSAR products, and users can save processing time and disk space while obtaining the results of InSAR time series analysis. In the LiCSBAS processing scheme, interferograms with many unwrapping errors are automatically identified by loop closure and removed. Reliable time series and velocities are derived with the aid of masking using several noise indices. The easy implementation of atmospheric corrections to reduce noise is achieved with the Generic Atmospheric Correction Online Service for InSAR (GACOS). Using case studies in southern Tohoku and the Echigo Plain, Japan, we demonstrate that LiCSBAS applied to LiCSAR products can detect both large-scale (>100 km) and localized (similar to km) relative displacements with an accuracy of <1 cm/epoch and similar to 2 mm/yr. We detect displacements with different temporal characteristics, including linear, periodic, and episodic, in Niigata, Ojiya, and Sanjo City, respectively. LiCSBAS and LiCSAR products facilitate greater exploitation of globally available and abundant SAR datasets and enhance their applications for scientific research and societal benefit. KW - InSAR KW - Sentinel-1 KW - time series analysis KW - deformation monitoring KW - tectonics KW - subsidence KW - automatic processing KW - global Y1 - 2020 U6 - https://doi.org/10.3390/rs12030424 SN - 2072-4292 VL - 12 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - von Specht, Sebastian A1 - Heidbach, Oliver A1 - Cotton, Fabrice Pierre A1 - Zang, Arno T1 - Uncertainty reduction of stress tensor inversion with data-driven catalogue selection JF - Geophysical journal international N2 - The selection of earthquake focal mechanisms (FMs) for stress tensor inversion (STI) is commonly done on a spatial basis, that is, hypocentres. However, this selection approach may include data that are undesired, for example, by mixing events that are caused by different stress tensors when for the STI a single stress tensor is assumed. Due to the significant increase of FM data in the past decades, objective data-driven data selection is feasible, allowing more refined FM catalogues that avoid these issues and provide data weights for the STI routines. We present the application of angular classification with expectation-maximization (ACE) as a tool for data selection. ACE identifies clusters of FM without a priori information. The identified clusters can be used for the classification of the style-of-faulting and as weights of the FM data. We demonstrate that ACE effectively selects data that can be associated with a single stress tensor. Two application examples are given for weighted STI from South America. We use the resulting clusters and weights as a priori information for an STI for these regions and show that uncertainties of the stress tensor estimates are reduced significantly. KW - Inverse Theory KW - Statistical Methods KW - Seismicity KW - tectonics KW - Kinematics of crustal KW - mantle deformation Y1 - 2018 U6 - https://doi.org/10.1093/gji/ggy240 SN - 0956-540X SN - 1365-246X VL - 214 IS - 3 SP - 2250 EP - 2263 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Forte, Adam M. A1 - Whipple, Kelin X. A1 - Bookhagen, Bodo A1 - Rossi, Matthew W. T1 - Decoupling of modern shortening rates, climate, and topography in the Caucasus JF - Earth & planetary science letters N2 - The Greater and Lesser Caucasus mountains and their associated foreland basins contain similar rock types, experience a similar two-fold, along-strike variation in mean annual precipitation, and were affected by extreme base-level drops of the neighboring Caspian Sea. However, the two Caucasus ranges are characterized by decidedly different tectonic regimes and rates of deformation that are subject to moderate (less than an order of magnitude) gradients in climate, and thus allow for a unique opportunity to isolate the effects of climate and tectonics in the evolution of topography within active orogens. There is an apparent disconnect between modern climate, shortening rates, and topography of both the Greater Caucasus and Lesser Caucasus which exhibit remarkably similar topography along-strike despite the gradients in forcing. By combining multiple datasets, we examine plausible causes for this disconnect by presenting a detailed analysis of the topography of both ranges utilizing established relationships between catchment-mean erosion rates and topography (local relief, hillslope gradients, and channel steepness) and combining it with a synthesis of previously published low-temperature thermochronologic data. Modern climate of the Caucasus region is assessed through an analysis of remotely-sensed data (TRMM and MODIS) and historical streamflow data. Because along-strike variation in either erosional efficiency or thickness of accreted material fail to explain our observations, we suggest that the topography of both the western Lesser and Greater Caucasus are partially supported by different geodynamic forces. In the western Lesser Caucasus, high relief portions of the landscape likely reflect uplift related to ongoing mantle lithosphere delamination beneath the neighboring East Anatolian Plateau. In the Greater Caucasus, maintenance of high topography in the western portion of the range despite extremely low (<2-4 mm/y) modern convergence rates may be related to dynamic topography from detachment of the north-directed Greater Caucasus slab or to a recent slowing of convergence rates. Large-scale spatial gradients in climate are not reflected in the topography of the Caucasus and do not seem to exert any significant control on the tectonics or structure of either range. (C) 2016 Elsevier B.V. All rights reserved. KW - tectonics KW - erosion KW - climate KW - dynamic topography KW - orogenic processes Y1 - 2016 U6 - https://doi.org/10.1016/j.epsl.2016.06.013 SN - 0012-821X SN - 1385-013X VL - 449 SP - 282 EP - 294 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Scherler, Dirk A1 - Bookhagen, Bodo A1 - Strecker, Manfred T1 - Tectonic control on Be-10-derived erosion rates in the Garhwal Himalaya, India JF - Journal of geophysical research : Earth surface N2 - Erosion in the Himalaya is responsible for one of the greatest mass redistributions on Earth and has fueled models of feedback loops between climate and tectonics. Although the general trends of erosion across the Himalaya are reasonably well known, the relative importance of factors controlling erosion is less well constrained. Here we present 25 Be-10-derived catchment-averaged erosion rates from the Yamuna catchment in the Garhwal Himalaya, northern India. Tributary erosion rates range between similar to 0.1 and 0.5mmyr(-1) in the Lesser Himalaya and similar to 1 and 2mmyr(-1) in the High Himalaya, despite uniform hillslope angles. The erosion-rate data correlate with catchment-averaged values of 5 km radius relief, channel steepness indices, and specific stream power but to varying degrees of nonlinearity. Similar nonlinear relationships and coefficients of determination suggest that topographic steepness is the major control on the spatial variability of erosion and that twofold to threefold differences in annual runoff are of minor importance in this area. Instead, the spatial distribution of erosion in the study area is consistent with a tectonic model in which the rock uplift pattern is largely controlled by the shortening rate and the geometry of the Main Himalayan Thrust fault (MHT). Our data support a shallow dip of the MHT underneath the Lesser Himalaya, followed by a midcrustal ramp underneath the High Himalaya, as indicated by geophysical data. Finally, analysis of sample results from larger main stem rivers indicates significant variability of Be-10-derived erosion rates, possibly related to nonproportional sediment supply from different tributaries and incomplete mixing in main stem channels. KW - Himalaya KW - erosion KW - tectonics KW - cosmogenic nuclides KW - channel steepness KW - stream power Y1 - 2014 U6 - https://doi.org/10.1002/2013JF002955 SN - 2169-9003 SN - 2169-9011 VL - 119 IS - 2 SP - 83 EP - 105 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Hoke, Gregory D. A1 - Giambiagi, Laura B. A1 - Garzione, Carmala N. A1 - Mahoney, J. Brian A1 - Strecker, Manfred T1 - Neogene paleoelevation of intermontane basins in a narrow, compressional mountain range, southern Central Andes of Argentina JF - Earth & planetary science letters KW - Neogene KW - Andes KW - surface uplift KW - tectonics KW - paleoelevation Y1 - 2014 U6 - https://doi.org/10.1016/j.epsl.2014.08.032 SN - 0012-821X SN - 1385-013X VL - 406 SP - 153 EP - 164 PB - Elsevier CY - Amsterdam ER -