ALBERT

Description: This study represents the first investigating potential kinematic boundary conditions for subduction erosion in a systematic manner. For the subduction erosional process, the aperture at the box's rear, which allowed rearward material loss, was shown to have the largest influence on obtained results. If the amount of material leaving the system was larger than the amount of material subducted at the wedge's toe, the margin evolved as erosional. We found the surface slope to be the second important parameter, which strongly controls the amount of basally eroded material.

Description: This document serves as a record of the processing standards, models & parameters adopted for the generation of monthly and weekly (aligned to GPS weeks) Level-2 gravity field data products by the GRACE Science Data System component at the GFZ German Research Centre for Geosciences.

Description: SEG-Y data of small-scale high-resolution controlled-source seismic experiment to investigate the mesoscopic fault structure of the Wadi Arava fault, Dead Sea Transform.

Description: In order to analyze mineralogical-geochemical changes occurring in whole rock reservoir samples (Stuttgart Formation) from the Ketzin pilot CO2 storage site, Brandenburg/Germany as well as to investigate single fluid-mineral reactions laboratory experiments and geochemical modeling were performed. The whole rock core samples of the Stuttgart Formation were exposed to synthetic brine and pure CO2 at experimental P-T conditions and run durations of 5.5 MPa/40 °C/40 months for sandstone and 7.5 MPa/40 °C/6 months for siltstone, respectively. Mineralogical changes in both sets of experiments are generally minor making it difficult to differentiate the natural variability of the whole rock samples from CO2-induced alterations. Results of sandstone experiments suggest dissolution of analcime, anhydrite, the anorthite component of plagioclase, chlorite + biotite, hematite and K-feldspar. Dissolution of anhydrite, the anorthite component of plagioclase and K-feldspar is also observed in siltstone experiments. During equilibrium simulations best matching models were ranked based on a mathematical statistical dispersion relation. The best matching model comprises a mineral combination of the albite component of plagioclase, anhydrite, dolomite, hematite, and illite. The equilibrium modeling showed that it is difficult to match K+, Fe2+ and SO4 2- brine concentrations simultaneously. The best matching subsets of the equilibrium models were finally run including kinetic rate laws. These kinetic simulations reveal that experimentally determined brine data was well matched, but reactions involving K+ and Fe2+ were not completely covered. Generally larger mismatches for dissolved Al3+ and Si4+ in all the completed simulations are most likely related to the sampling strategy and respective inaccuracies in the measured concentrations of dissolved Al3+ and Si4+. The kinetic simulation suppressing mineral precipitation yields best matches with experimental observations. The modeling shows acceptably well matches with measured brine ion concentrations, and the modeling results identified primary minerals as well as key chemical processes. It was also shown that the modeling approach is not capable of completely covering complex natural systems. Experiments on mineral separates were conducted with 2 M NaCl brine and pure CO2 using siderite, illite and labradorite samples. Experimental P-T conditions were 20 (30) MPa and 80 °C; run durations were one (siderite), two (illite) and three weeks (labradorite), respectively. Based on the acquired set of mineralogical-geochemical data the distinct experiments show: (i) dissolution of ankerite and stable siderite, which is therefore interpreted to be a potential CO2 trapping phase, (ii) preferred dissolution of the Ca-smectite component out of the illite-smectite mixed-layer mineral and (iii) dissolution of labradorite, respectively. No mineral precipitates (e.g. carbonate phases) were detected in any of the conducted laboratory experiments, and only one single kinetic simulation predicts the formation of minute amounts of dolomite. Based on the data acquired during this dissertation the mineralogical-geochemical effects of CO2 are minor, and the (chemical) integrity of the Ketzin reservoir system is not significantly affected by injected CO2.

Description: Reinsch et al. (2013) describe the installation of a novel fibre optic cable behind the anchor casing of the geothermal well HE-53, Hellisheiði geothermal field, SW Iceland. Within this data publication, DTS temperature data, acquired together with optical time domain reflectometry (OTDR) data during three different field campaigns are presented. Data have been acquired during the installation in spring 2009, during the onset of a production test in summer 2009 and after a 8.5 month shut-in period in summer 2010.

Description: We recover coseismic static surface deformation by double integration of strong motion accelerometric data. Compared to GPS measurement, the advantage of strong motion data is that they have the potential to provide real-time coseismic static displacements. Strong motion data, however, has the classic problem of baseline offsets which produce unrealistic displacements after double integration is applied. We adopted a bilinear line fitting of empirical baseline correction method to overcome such problem. We investigate the improvement methods of baseline correction that constrain the maximum flatness of the displacement trace and use the cumulative energy ratio as a threshold. We apply the methods to data sets of the 2003, Mw 8.3 Tokachi-Oki earthquake, the 2007, Mw 7.7 Tocopilla earthquake, the 2010, Mw 7.8 Mentawai earthquake and the 2011, Mw 9.0 Tohoku earthquake. We show that, in general, the results of strong motion derived displacements are comparable to nearby GPS data for most data sets, although for far-field data the method may lead to poor results. It confirms that cumulative energy ratio is appropriate to be used as a threshold of baseline correction method. The very large and very good quality of boreholes strong motion data of the Tohoku earthquake gives opportunity to investigate the method deeply. We analyze the dependency of the method on hypocenter distance, magnitude and rupture model of the earthquake. We found that the method has a strong dependency on the given parameters, particularly on hypocenter distance. We also show that the method should be distinguished for horizontal and vertical components. Using our improvement method in this study, the deviations of vector length between strong motion derived displacements and nearby GPS data either for horizontal or vertical components, are significantly minimized. Further study, we optimize the use of valuable rapid static displacement data obtained from strong motion or GPS near-source station. We introduce a centroid grid search method to calculate the moment magnitude by using Okada (1985) model. Our method calculates reasonable moment magnitude using data even only from single station. This method can be done very rapidly within about 5 minutes. It provides crucial information e.g. for making tsunami warning decision.

Description: [...] The approach followed in this study is based on the detailed analyses of the relationships between thermal conductivity of rock-forming minerals, which are most abundant in sedimentary rocks, and the properties measured by standard logging tools (i.e., gamma ray, density, sonic interval transit time, hydrogen index, and photoelectric factor). By using multivariate statistics separately for clastic, carbonate and evaporite rocks, the findings from these analyses allow the development of prediction equations from large artificial data sets that predict matrix thermal conductivity within an error of 4 to 11%, without being affected by the limitations mentioned above.

Description: The intention of this article is to present the definitions of different functionals of the Earth’s gravity field and possibilities for their approximative calculation from a mathematical representation of the outer potential.

Description: Within this thesis, passive seismic data collected during the two-year TIPAGE deployment in Tajikistan and Kyrgyzstan from 2008 to 2010, are analyzed. This is the first modern digital seismological dataset for this politically unstable region, all previous studies either relied on globally recorded data or some short-term deployments of analog stations in Afghanistan during the late 1960s and 70s. Modern seismological techniques applied to the collected digital seismic data provide a wealth of new constraints on regional crustal and sub-crustal structure, leading to a better understanding of active tectonic processes.

Description: For the present work we carry out our research with two objectives : (A) Constructing a high resolution three-dimensional velocity model of the upper mantle. (B) Probing convection and deformation of the mantle through analysis of seismic anisotropy. In our study we determine the three dimensional Sv wave speed and the azimuthal anisotropy model by analyzing vertical component multimode Rayleigh wave seismograms. We use data of broadband stations within and around China. We construct the three dimensional model using a two step procedure.

Description: Film 6: "Scientific Drilling at the pilot site Ketzin" (Length 08:53) "At the pilot site Ketzin three wells were drilled to depths of 750 to 810 meters in 2007 before the start of CO2 injection ..." In 2011 a fourth, and 2012, the fifth well was constructed. This last well (Ktzi 203) for the first time offers the unique opportunity to gain samples (cores) from a storage reservoir that have been exposed to CO2 for more than four years. How were these samples (cores) gained and studied? Production Year: 2012

Description: The goal of this thesis is to close these gaps (exclude aliasing effect, improve the sensitivity towards short period waves and increase the resolution of the results) and prove, that the RO technique is a powerful tool to derive high resolution global results of absolute momentum flux.

Description: This publication is a result of the 11th TRACE conference (Tree Rings in Archaeology, Climatology and Ecology) organized by the GFZ German Research Centre for Geosciences, Deutsches Archäologisches Institut (DAI), Berlin and the Thünen Institute of Forest Ecosystems, Eberswalde, on May 08th – 12th 2012 in Potsdam and Eberswalde, Germany. [...] After review 25 short papers are published in this volume giving an overview of the wide spectrum of fields in tree-ring research.