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Found 227 results.

Sub project: The Geothermal Field of the Chesapeake Bay Impact Structure

Das Projekt "Sub project: The Geothermal Field of the Chesapeake Bay Impact Structure" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Geophysikalisches Institut durchgeführt. Within the frame of the aims of the ICDP Chesapeake Bay Impact Structure (CBIS) Project, our primary goal is to perform an investigation of the present geothermal and hydraulic regime of the central part of this impact structure. To reach this aim we will determine local and regional heat flow variations in lateral and vertical direction in the CBIS area in cooperation with our partners in Berlin, Moscow, Prague and colleagues from USGS. The results of this investigation will contribute to the hydro-geological research concerning the threatening of the fresh groundwater resources of the region by the CB impact brines. Another aim of our project is to investigate the possibilities to extend the variability of the models for the interpretation of transient thermal signals, caused in boreholes e.g. by artesian outflow of water.

Sub project: Imaging Induced Seismicity at the KTB

Das Projekt "Sub project: Imaging Induced Seismicity at the KTB" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Geophysik durchgeführt. The observation of naturally or artificially generated acoustic emissions (i.e., small earthquakes) by seismic networks is a powerful tool to image transport processes in the earth. During the injection experiments at the KTB a large number of events were observed. The precise spatio-temporal characterization of the seismic events is of utmost importance since all following interpretations (e.g., transport properties) rely entirely on this result. The localization of the events depends on the model used for the localization. The anisotropy of the KTB rocks is a well known feature but was not considered for the localization. Previous studies demonstrate that this leads to severe errors in the location of events. In this study we will first determine the anisotropic elastic features from the comprehensive KTB VSP data sets using 3-D anisotropic tomography for P- and S-waves. This step is essential for the localization. The obtained tomographic anisotropic 3-D model will then be used for the localization of the acoustic emissions of the 2000 and 2004 injection experiments. A newly developed technology based on reversed modelling or time reversed acoustic mirrors will be used to image the events. This techniques does not require picking of events and increases the detection level of the network owing to the stacking character of the method and allows to locate arrivals not visible in the individual seismograms of the network.

Sub project: Seismic site characterization in and around the COSC-1 drillhole

Das Projekt "Sub project: Seismic site characterization in and around the COSC-1 drillhole" wird vom Umweltbundesamt gefördert und von Technische Universität (TU) Bergakademie Freiberg, Institut für Geophysik und Geoinformatik durchgeführt. The project COSC (Collisional Orogeny in the Scandinavian Caledonides) focuses on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, both in the past and in recent active mountain belts (Gee et al., 2010). The Scandinavian Caledonides provide a well preserved example of Paleozoic plate collision, where the surface geology in combination with geophysical data provide control of the geometry of the Caledonian structure, both of the allochthon and the underlying autochthon, including a shallow W-dipping décollement surface on a thin skin of Cambrian black shales beneath the Caledonian thrust sheets. The structure of the basement underneath the décollement is highly reflective and apparently dominated by mafic sheets intruded into either late Paleoproterozoic granites or Mesoproterozoic volcanics and sandstones. The COSC project will examine the structure and physical conditions of these units, in particular the Caledonian nappes ('hot' allochthon) and the underlying basement, with two approximately 2.5 km deep drillholes, located near Åre and Mörsil in western Jämtland (http://www.sddp.se/COSC). In addition to that, the drillholes will provide unique information about the present temperature gradient in the Caledonides, the porosity and permeability of the rock formations, and the petrophysical properties of the rocks at depth. Existing regional seismic and magnetotelluric data have imaged the geometry of the upper crust, and pre-site seismic reflection survey were preformed in 2010 and 2011 to better define the exact drill site locations (Hedin et al., 2012). This present proposal is dedicated to complement these surface seismic measurements by drillhole-based investigations to better resolve and define the small-scale structures (including lithological boundaries, steeply dipping fault segments, fracture sets, etc.) around the drillhole COSC-1. This will be achieved by a combination of seismic transmission and reflection experiments using a 3C borehole geophone system and complemented by 3C geophones at the surface, where sources and surface receivers will be aligned at different azimuths and centred around the borehole location. The data processing will employ recently developed advanced imaging techniques and will focus on, amongst other things, the analysis of anisotropic effects caused by aligned fractures and faults and their relation to the stress regime. The results of our investigations will be high-resolution images of the fine-scale structure of faults and fractures around the borehole. This information is vital not only for a reliable spatial extrapolation of the structural and petrophysical properties observed in the borehole, but also for a thorough understanding of the tectonic and geodynamic setting, including, but not limited to, the past and present stress regime.

Sub project: Participation in a site survey cruise off Costa Rica on RV Ewing

Das Projekt "Sub project: Participation in a site survey cruise off Costa Rica on RV Ewing" wird vom Umweltbundesamt gefördert und von Universität Bremen, Fachbereich 05: Geowissenschaften, Fachgebiet Meerestechnik - Sensorik durchgeführt. Im vorgeschlagenen Forschungsprogramm sollen konventionelle Wärmestromdichtemessungen vor Costa Rica ergänzt werden durch Messungen des Temperaturgradienten über einen Tiefenbereich von 6 m. Dieses Gebiet seewärts des Grabens und nördlich der RSB-Linie ist durch einen extrem niedrigen Wärmestrom gekennzeichnet, dessen Ursache bislang nicht bekannt ist. Diese Wärmestromdichtemessungen zusammen mit seismischen Vermessungen werden im April/Mai 2001 vom amerikanischen Forschungsschiff RV Ewing aus durchgeführt werden. Prof. Dr. A. Fisher (Univ. California at Santa Cruz) hat ein Mitglied meiner Arbeitsgruppe eingeladen, an den Wärmestromdichtemessungen teilzunehmen und die Messungen durch unsere spezielle Sonde zu ergänzen... Ein Schwerpunkt der Messungen wird in Bereichen mit Wassertiefen größer als 4.000 m liegen, da dort die konventionelle Wärmestromsonde wegen der Drucklimitierung der Elektronikdruckbehälter nicht mehr eingesetzt werden kann. Der andere Schwerpunkt liegt auf den Messungen langer Temperaturprofile im Graben, um dort evtl. vorhandene nichtstationäre Einflüsse durch hohe Sedimentationsraten, Variationen der Bodenwassertemperatur oder durch advektiven Transport aufzudecken. Die Ergebnisse werden mit den von Langseth und Silver (1996) publizierten Ergebnissen wie auch den Daten von Leg 170 (Silver et al., 2000; Ruppel and Kinoshita 2000) verknüpft werden. Sie liefern damit ein Bild der regionalen Verteilung des Wärmestromes und zusätzliche site survey Informationen für Leg 203.

Sub project: Active and Passive Seismic Imaging of the San-Andreas-Fault System

Das Projekt "Sub project: Active and Passive Seismic Imaging of the San-Andreas-Fault System" wird vom Umweltbundesamt gefördert und von Technische Universität (TU) Bergakademie Freiberg, Institut für Geophysik und Geoinformatik durchgeführt. High-quality active seismic data are currently acquired in the vicinity of the San-Andreas-Fault-System within the EarthScope project SAFOD. Our proposal aims at processing and interpretation of these data sets using newly developed techniques in order to derive a high-resolution image of the subsurface. On one hand we want to employ Fresnel-Volume-Migration to two of these data sets for an improved and more detailed image of the internal structure of the fault system compared with already existing images. On the other hand we want to locate local earthquakes from the vicinity of the fault system using a new efficient procedure followed by a study of their relationship to the structural features of the fault system. In summary these investigations provide an important contributation to the understanding of the physical and chemical processes that control the motion and earthquake triggering at such an active plate boundary.

Sub project: ODP Pre-Site Survey Argentine Basin

Das Projekt "Sub project: ODP Pre-Site Survey Argentine Basin" wird vom Umweltbundesamt gefördert und von Universität Bremen, Fachgebiet Meerestechnik / Umweltforschung durchgeführt.

Sub project: Multiscale seismic imaging of the San-Andreas-Fault system

Das Projekt "Sub project: Multiscale seismic imaging of the San-Andreas-Fault system" wird vom Umweltbundesamt gefördert und von Technische Universität (TU) Bergakademie Freiberg, Institut für Geophysik und Geoinformatik durchgeführt. The main objective of project SAFOD (San-Andreas-Fault-Observatory-at-Depth) is to answer fundamental questions about the physical and chemical processes controlling faulting and earthquake generation within a major plate-bounding fault. In that respect significant progress has been achieved recently by acquiring and analyzing various geoscientific data sets. We propose to contribute to this understanding by constructing detailed crustal transects across this plate boundary zone from seismic imaging on different scales. On one hand we want to reprocess existing industry seismic reflection data and USGS seismic refraction data ('SJ6' transect) using innovative seismic imaging techniques (Fresnel-Volume-Migration) in order to map and to analyze its large-scale structural inventory and tectonic environment. We expect that such a reprocessing will resolve in particular the large-scale depth structure and the deep roots of the San-Andreas-Fault system, which has not yet been achieved using recent seismic data sets. On the other hand we want to process microseismic data recorded within the SAFOD borehole, which have illuminated nearby branches of the fault system, using reflection seismic techniques in order to reveal the fine-scale fault structure in the close vicinity of the borehole. These imaging results can be directly used as a calibration tool for seismological investigations as well as borehole studies during the ongoing drilling phase at SAFOD. This multiscale approach will deliver comprehensive seismic images which can be used as a basis for a profound characterization of the subsurface environment and can decisively contribute to the understanding of the seismogenic processes at this major plate bounding fault system.

Sub project: Combined OBS and ODP Log Investigation of BSR signatures at Hydrate Ridge

Das Projekt "Sub project: Combined OBS and ODP Log Investigation of BSR signatures at Hydrate Ridge" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt.

Teilprojekt: Auswertung seismischer Profile für ODP 'Leg 161'

Das Projekt "Teilprojekt: Auswertung seismischer Profile für ODP 'Leg 161'" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt.

Sub project: Pattern recognition in electrical images - digital image analysis with special focus on Gas Hydrate Leg 204

Das Projekt "Sub project: Pattern recognition in electrical images - digital image analysis with special focus on Gas Hydrate Leg 204" wird vom Umweltbundesamt gefördert und von RWTH Aachen University, E.ON Energy Research Center (E.ON ERC) Institute for Applied Geophysics and Geothermal Energy (GGE) durchgeführt. Electrical images are widely used in oil industry for borehole inspection and reservoir characterisation. They consist of artifically colour-coded micro-resistivity measurements on the borehole wall. In ODP these are commonly used to study the internal structure of the oceanic crust. At present, the reconstruction of lithology from electrical images is purely based on visual inspection and subjective interpretation. Our objectives are to (1) develop methods for an object- and texture-based pattern recognition of electrical images; (2) develop methods for an automatic classification of rocks; (3) apply this methodology to study the occurrence and characteristics of gas hydrates at ODP Leg 204. Avaible methods from seismic data interpretation and biomedical imaging will be adapted for use with resistive images. In particular, we will implement an algorithm for automatic object identification for a study of the internal rock morphology with respect to sediments drilled at ODP Leg 204. This way, resistivity anomalies caused by gas hydrates will localised them in electrical images. Their proportion, size, and shape will be quantified in order to analyse anisotropy and spatial heterogeneity of identified gas hydrates. Finally, we will correlate the 1D information from all available boreholes and interpolate them into a 2D map of the gas hydrates distribution at Leg 204.

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