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 - Muksin, Umar A1 - Haberland, Christian A1 - Nukman, Mochamad A1 - Bauer, Klaus A1 - Weber, Michael H. T1 - Detailed fault structure of the Tarutung Pull-Apart Basin in Sumatra, Indonesia, derived from local earthquake data JF - Journal of Asian earth sciences N2 - The Tarutung Basin is located at a right step-over in the northern central segment of the dextral strike-slip Sumatran Fault System (SFS). Details of the fault structure along the Tarutung Basin are derived from the relocations of seismicity as well as from focal mechanism and structural geology. The seismicity distribution derived by a 3D inversion for hypocenter relocation is clustered according to a fault-like seismicity distribution. The seismicity is relocated with a double-difference technique (HYPODD) involving the waveform cross-correlations. We used 46,904 and 3191 arrival differences obtained from catalogue data and cross-correlation analysis, respectively. Focal mechanisms of events were analyzed by applying a grid search method (HASH code). Although there is no significant shift of the hypocenters (10.8 m in average) and centroids (167 m in average), the application of the double difference relocation sharpens the earthquake distribution. The earthquake lineation reflects the fault system, the extensional duplex fault system, and the negative flower structure within the Tarutung Basin. The focal mechanisms of events at the edge of the basin are dominantly of strike-slip type representing the dextral strike-slip Sumatran Fault System. The almost north south striking normal fault events along extensional zones beneath the basin correlate with the maximum principal stress direction which is the direction of the Indo-Australian plate motion. The extensional zones form an en-echelon pattern indicated by the presence of strike-slip faults striking NE SW to NW SE events. The detailed characteristics of the fault system derived from the seismological study are also corroborated by structural geology at the surface. (C) 2014 Elsevier Ltd. All rights reserved. KW - Focal mechanism KW - Seismicity KW - Structural geology KW - Extensional duplex KW - Flower structure KW - Sumatran fault KW - Pull-Apart Basin Y1 - 2014 U6 - https://doi.org/10.1016/j.jseaes.2014.09.009 SN - 1367-9120 SN - 1878-5786 VL - 96 SP - 123 EP - 131 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Kottmeier, Christoph A1 - Agnon, Amotz A1 - Al-Halbouni, Djamil A1 - Alpert, Pinhas A1 - Corsmeier, Ulrich A1 - Dahm, Torsten A1 - Eshel, Adam A1 - Geyer, Stefan A1 - Haas, Michael A1 - Holohan, Eoghan A1 - Kalthoff, Norbert A1 - Kishcha, Pavel A1 - Krawczyk, Charlotte A1 - Lati, Joseph A1 - Laronne, Jonathan B. A1 - Lott, Friederike A1 - Mallast, Ulf A1 - Merz, Ralf A1 - Metzger, Jutta A1 - Mohsen, Ayman A1 - Morin, Efrat A1 - Nied, Manuela A1 - Roediger, Tino A1 - Salameh, Elias A1 - Sawarieh, Ali A1 - Shannak, Benbella A1 - Siebert, Christian A1 - Weber, Michael T1 - New perspectives on interdisciplinary earth science at the Dead Sea: The DESERVE project JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - The Dead Sea region has faced substantial environmental challenges in recent decades, including water resource scarcity, similar to 1 m annual decreases in the water level, sinkhole development, ascending-brine freshwater pollution, and seismic disturbance risks. Natural processes are significantly affected by human interference as well as by climate change and tectonic developments over the long term. To get a deep understanding of processes and their interactions, innovative scientific approaches that integrate disciplinary research and education are required. The research project DESERVE (Helmholtz Virtual Institute Dead Sea Research Venue) addresses these challenges in an interdisciplinary approach that includes geophysics, hydrology, and meteorology. The project is implemented by a consortium of scientific institutions in neighboring countries of the Dead Sea (Israel, Jordan, Palestine Territories) and participating German Helmholtz Centres (KIT, GFZ, UFZ). A new monitoring network of meteorological, hydrological, and seismic/geodynamic stations has been established, and extensive field research and numerical simulations have been undertaken. For the first time, innovative measurement and modeling techniques have been applied to the extreme conditions of the Dead Sea and its surroundings. The preliminary results show the potential of these methods. First time ever performed eddy covariance measurements give insight into the governing factors of Dead Sea evaporation. High-resolution bathymetric investigations reveal a strong correlation between submarine springs and neo-tectonic patterns. Based on detailed studies of stratigraphy and borehole information, the extension of the subsurface drainage basin of the Dead Sea is now reliably estimated. Originality has been achieved in monitoring flash floods in an arid basin at its outlet and simultaneously in tributaries, supplemented by spatio-temporal rainfall data. Low-altitude, high resolution photogrammetry, allied to satellite image analysis and to geophysical surveys (e.g. shear-wave reflections) has enabled a more detailed characterization of sinkhole morphology and temporal development and the possible subsurface controls thereon. All the above listed efforts and scientific results take place with the interdisciplinary education of young scientists. They are invited to attend joint thematic workshops and winter schools as well as to participate in field experiments. (C) 2015 The Authors. Published by Elsevier B.V. KW - Climate KW - Water balance KW - Flash floods KW - Seismicity KW - Sinkholes KW - Education Y1 - 2016 U6 - https://doi.org/10.1016/j.scitotenv.2015.12.003 SN - 0048-9697 SN - 1879-1026 VL - 544 SP - 1045 EP - 1058 PB - Elsevier CY - Amsterdam ER -