ALBERT

Description: The final report contains a description of the results obtained within a research contract between IRE RAS and GFZ Potsdam during the period April-November 2004. The objectives of investigation included (1) the radio-holographic methods for obtaining vertical profiles of the vertical gradients of physical parameters in the atmosphere, (2) radio holographic methods for atmospheric, ionospheric and stratospheric waves, and (3) validation of the software with GPS/MET (GPS/METeorology, e.g., Rocken et al. 1997) and CHAMP (CHAllenging Minisatellite Payload, e.g., Reigber et al. 2005) data and final report with recommendations.

Description: Late Miocene to Quaternary volcanic rocks from the frontal arc to the back-arc region of the Central Volcanic Zone in the Andes show a wide range of delta 11B values (+4 to -7 ‰) and boron concentrations (6 to 60 ppm). Positive delta 11B values of samples from the volcanic front indicate involvement of a 11B-enriched slab component, most likely derived from altered oceanic crust, despite the thick Andean continental lithosphere, and rule out a pure crust-mantle origin for these lavas. The delta 11B values and B concentrations in the lavas decrease systematically with increasing depth of the Wadati-Benioff Zone. This across-arc variation in delta 11B values and decreasing B/Nb ratios from the arc to the back-arc samples are attributed to the combined effects of B-isotope fractionation during progressive dehydration in the slab and a steady decrease in slab-fluid flux towards the back arc, coupled with a relatively constant degree of crustal contamination as indicated by similar Sr, Nd and Pb isotope ratios in all samples. Modelling of fluid-mineral B-isotope fractionation as a function of temperature fits the across-arc variation in delta 11B and we conclude that the B-isotope composition of arc volcanics is dominated by changing delta 11B composition of B-rich slab-fluids during progressive dehydration. Crustal contamination becomes more important towards the back-arc due to the decrease in slab-derived fluid flux. Because of this isotope fractionation effect, high delta 11B signatures in volcanic arcs need not necessarily reflect differences in the initial composition of the subducting slab. Three-component mixing calculations for slab-derived fluid, the mantle wedge and the continental crust based on B, Sr and Nd isotope data indicate that the slab-fluid component dominates the B composition of the fertile mantle and that the primary arc magmas were contaminated by an average addition of 15 to 30 % crustal material.

Description: Die im Norddeutschen Becken vorkommenden hochsalinaren, heißen Tiefenwässer besitzen ein beträchtliches Wärmepotential, das bisher in Neustadt-Glewe, Neubrandenburg und Waren zur Energiegewinnung genutzt wird. Das Ziel der vorliegenden Arbeit bestand zum einen darin, die Herkunft und die Genese dieser Solen und der in ihnen gelösten Stoffe zu rekonstruieren. Ein zweiter Schwerpunkt bestand in der Ermittlung geochemischer Parameter, die für einen problemlosen Langzeitbetrieb geothermischer Anlagen und somit für deren Wirtschaftlichkeit von Bedeutung sind. Die untersuchten Solen stammten aus Aquiferen, die durch fünf Bohrungen (Neubrandenburg, Waren, Rheinsberg, Neustadt-Glewe, Hamburg-Allermöhe) in Tiefen von 1250 bis 3250 m (54 bis l28°C) erschlossen wurden. Alle untersuchten Na-Cl-Solen wurden aus Sandsteinaquiferen des Keuper (Contorta!Postera-Schichten) gefördert, für die mit zunehmender Tiefe steigende TDS-Gehalte (134 bis 224 g/1) charakteristisch sind. Die Zusammensetzung der gelösten Feststoffe blieb über einen Zeitraum von 3 Jahren konstant. Die Br/CJ-Verhältnisse der Solen sind kleiner als in eingedampftem Meerwasser. Dies und 811B-Werte von +23.8 %o bis +36.3 %o indizieren die Herkunft des Salzgehaltes durch Auflösung/Laugung von Salzen. Das Gas-Wasser-Volumenverhältnis in Proben geothermisch genutzter Solen liegt bei max. 1:10. Die Gasphase wird von C02, N2 und CH4 dominiert, wobei der Gehalt an C02 und CH4 mit der Tiefe zunimmt. Als Spurengase treten He, Ar, H2 und weitere Kohlenwasserstoffe auf (jeweils 〈1 Vol.-%). Die Gasphase des Thermalwassers Neustadt-Giewe zeigte über einen Zeitraum von 2 Jahren keine Änderung in ihrer Zusammensetzung. Periodische Schwankungen in sehr kleinen Konzentrationsbereichen während einer mehrtägigen Gasmeßkampagne korrelieren mit den Erdgezeiten. Die N2-Ar-He-Verhältnisse zeigen, daß es sich um tiefzirkulierende Oberflächenwässer handelt. Untermauert wird diese Interpretation durch die sehr niedrigen 3HefHe-Verhältnisse (R!Ra:S;O.Ol), die keine Mantelheliumkomponente anzeigen, sowie die gegenüber Luft (295.5) leicht erhöhten 40 Ar/36 Ar-Verhältnisse von bis zu 367.5. He-Akkumulationsalter als scheinbare Verweildauer der Solen von 20 bis 50 Ma wurden berechnet. Das Tiefenwasser von NeustadtGiewe besaß gegenüber den anderen Lokationen erhöhte Kohlenwasserstoffgehalte. Die 813C1,2,3- Werte weisen auf thermogenetische Kohlenwasserstoffe und auf ein marines Ausgangsmaterial mit einer Reife, die einer Vitrinitreflektion von etwa 1.2 % entspricht, hin. Die Herkunft aus Corgreichen Zechstein-Sedimenten ist wahrscheinlich, organisches Material des wesentlich tiefer liegenden Karbons scheidet als Quelle aus. Die 8180- und öD-Werte der Wässer zeigen an, daß meteorisches Wasser bei der Genese eine bedeutende Rolle gespielt hat. Die ermittelte isatopische Zusammensetzung der meteorischen Komponente weicht von heutigen Niederschlagswässern ab und weist einen letztmaligen Kontakt mit der Atmosphäre zu einer Zeit deutlich wärmeren Klimas als das heutige nach. Die in einem Thermalwasser vorhandenen Gase können die technologische Eignung der Sole und den Betrieb einer geothermischen Anlage maßgeblich beinflussen (Scaling, Auftreten brennbarer Gase, Entlösung von Gasen). Bei Vorhandensein Corg-reicher Sedimente nimmt die Wahrscheinlichkeit des Auftretens brennbarer Gase in Wässern aus größerer Tiefe, die durch ihre höhere Temperatur wirtschaftlicher sind, zu. Um die Entgasung eines Tiefenwassers innerhalb einer Anlage zu verhindem und somit Scaling und unkontrolliertes Entgasen zu minimieren, wurde anhand Literaturdaten exemplarisch für den Thermalwasserkreislauf der Anlage Neustadt-Giewe (Sole mit den höchsten Gasgehalten) ein Mindestanlagendruck berechnet. Danach sind etwa 2 bar ausreichend, um ein Entgasen der Sole zu verhindern; Strömungseffekte erfordern jedoch eine Erhöhung des Anlagendrucks auf etwa 4 bar. Die zeitliche Konstanz in der Zusammensetzung der gelösten Feststoffe und der Gasphase über einen Zeitraum von 2 bzw. 3 Jahren zeugt von einer relativ großen räumlichen Homogenität der Aquifere, wodurch der Betrieb der Anlagen durch Änderungen in der chemischen Zusammensetzung der Solen kaum gefährdet zu sein scheint. Die Ergebnisse der vorliegenden Arbeit haben gezeigt, daß sowohl bei der hydrodynamischen Vorerkundung als auch während des Betriebes eines geothermischen Heizwerkes die genaue Kenntnis der Gasmengen und der Gaszusammensetzung von entscheidender Bedeutung ist.

Description: Deep seated hydrothermal brines in the North German Basin have a considerable heat potential, which is currently used for geothermal energy recovery in Neustadt-Glewe, Neubrandenburg and Waren. One aim of this study was to reconstruct the origin of these brines and their dissolved substances. Another goalwas to determine geochemical parameters which are critically influence the long-term operation, and hence the econornic viability of geothermal plants. The brines come from aquifers which have been accessed by 5 boreholes (Neubrandenburg, Waren, Rheinsberg, Neustadt-Glewe, Hamburg-Allermöhe) in depths from 1250 to 3250 m (54 to 128 °C). All investigated Na-Cl-brines were produced from sandstone aquifers of the Keuper (Contorta!Postera layers). Typically, TDS-values (134 to 224 g/1) increase with depth. The compositions of the dissolved solids were constant during 3 years. The Br/Cl ratios of the brines are lower than evaporated sea water. This, and 811B-values of +23.8 %o up to +36.3 %o indicate dissolution/leaching of salt as the origin of the salt content. The gas-water volume ratio of samples from brines used for geothermal energy recovery are less than around 1:10. The gas phase is dorninated by C02, N2 and C~ with higher C02- and C~ contents with increasing depths. He, Ar, H2 and other hydrocarbons exist as traces ( 〈1 vol.% each). The gas phase of the thermal water from Neustadt-Giewe showed no changes in its composition during 2 years. Small · periodical variations in the concentrations obtained from gas monitaring over several days correlate with the earth tides. The N2-Ar-He ratios show that the waters are deep-circulating meteoric waters. This interpretation is supported by very low 3HefHe ratios (R!Ra:S;O.Ol), which show no mantle helium, and 40 ArP6 Ar ratios up to 367.5, which are slightly enhanced compared to air (295.5). He accumulation ages, taken as the apparent residence time of the brines, were calculated to be 20 to 50 Ma. Compared to the other locations the formation water from Neustadt-Giewe contained enhanced hydrocarbon contents. The 813C1,2,3 values point to thermogenic hydrocarbons and to a marine source rock with a maturity corresponding to about 1.2 % vitrinite reflectivity. An origin from Corg-rich Zechstein sediments seems probable, organic material from significantly deeper-seated Carboniferous formations can be ruled out. The 8180 and ÖD values of the waters confirm that meteoric water played an important role in the brine genesis. The determined isotopic composition of the meteoric component deviates from recent precipitation and indicates a last contact with the atmosphere at a time when climate conditions were significantly warmer than today. Gases dissolved in thermal waters can significantly affect both the technological suitability of a brine and the operation of a geothermal heat plant (scaling, degassing, occurence of flammable gases). If Corg-rich sedimentary rocks occur, the probability of the occurence of flammable gases increases in waters from larger depths, which are more economic due to their higher temperature. The pressure needed to prevent degassing inside a plant and thus to rninirnize scaling and uncontrolled degassing was calculated for the example of the thermal water cycle at Neustadt-Giewe (brine with the highest gas content). About 2 bars are sufficient to prevent degassing; however, flow effects require increasing the pressure up to about 4 bars. The constant composition of both the dissolved solids and gases over a period of 2 to 3 years is a sign of a relatively large spatial uniformity of the aquifers. Therefore the continuous operation of the plants seems unlikely to be endangered by a change in the chernical composition of the brines. The results of this study have shown that during the hydrodynarnic reconnaissance as weil as during the operation of a geothermal heat plant, precise knowlegde of the gas concentration is of essential importance.

Description: This manual outlines the characteristics and structure of the software and describes how to use the software. The principles and new features are outlined systematically and referred partly to existing references. Numerical examples of multi-functions and internal tests as well as external comparisons are given.

Description: We review the historical, geological, tide-gauge, GPS and gravimetric evidence advanced in favour of or against continuing land uplift around Hudson Bay, Canada. After this, we reanalyse the tide-gauge and GPS data for Churchill using longer time series than those available to previous investigators. The dependence of the mean rate of relative sea-level change obtained on the length and mid-epoch of the observation interval considered is investigated by means of the newly developed linear-trend analysis diagram. For studying the shorter-period variability of the tide-gauge record, the continuous-wavelet transform is used. The mean rate of land uplift obtained from GPS is based on a new analysis using IGS solutions of GFZ. Furthermore, sea-level indicators from the Churchill region representing the relative sea-level history during the past 8000 a are included. Finally, the four types of observable are jointly inverted in terms of mantle viscosity. The optimum values are 3×10^20 Pa s and 1.6 × 10^22 Pa s for the upper- and lower-mantle viscosities, respectively.

Description: Ziel dieser Arbeit ist die Quantifizierung von Modalbeständen magmatischer Gesteine anhand ihrer Infrarot-Spektren, basierend auf einer spektralen Einzelmineralanalyse. Dazu wurde eine neue, modellbasierte, spektrale Entmischungsmethode entwickelt. Diese Methode basiert auf reflexionsspektroskopischen Messungen im thermalen Infrarot von 8 - 14 μm, da in diesem Wellenlängenbereich silikatische Minerale und damit auch magmatische Gesteine ihre stärksten Spektralmerkmale (Reststrahlenbanden) aufweisen. Als Grundlage dienten Gesteinsproben des präkambrischen Gesteinskomplex Mt. Timna in Südisrael, der sich aus verschiedenen granitoiden Gesteinen und einer ultrabasischen Gesteinseinheit zusammensetzt. Die hier vorgestellte Arbeit entstand im Zusammenhang mit vorbereitenden Untersuchungen zur Entwicklung neuer Analysemethoden für einen neuen hyperspektralen Thermalsensors (ARES), der ab 2005 vom GFZ und dem DLR operationell betrieben werden soll.

Description: Der glazio-isostatische Ausgleich in Island als Folge des Abschmelzens der größten europäischen Eiskappe, dem Vatnajökull, verursacht zeitliche Änderungen der Schwere und Landhebung. Nach Auswertung der Schweredaten zeigt sich ein charakteristisches Verhalten. Die Schwereänderungsrate beträgt ca. -4 mikroGal/a am Eisrand (50 km Entfernung vom Eiszentrum)und ca. 1 mikroGal/a in Höfn (75 km Entfernung vom Eiszentrum). In größeren Entfernungen vom Eiszentrum (150 bis 250 km) werden die Raten kleiner als 1 mikroGal/a und nähern sich schließlich Null. Vorwärtsmodellierung liefert eine Lithosphärenmächtigkeit von 10 bis 15 km. Die Asthenosphärenviskosität ist 3 x 1017 bis 1 x 1018 Pa s. Diese Werte bestätigen frühere Resultate aus GPS-, seismischen und theoretischen Untersuchungen. Eine deutlich bessere Anpassung an die Meßdaten ergibt sich für erhöhte Asthenosphäremächtigkeit (165 bis 170km). Vermutlich reflektiert dies die spezielle Lage Islands oberhalb eines Plumes.

Description: This report is also published as Scientific Report No. 04-9 of the Danish Meteorological Institute.

Description: Die Arbeit untersucht die Möglichkeiten einer Anwendung der Aerogravimetrie bei der Schwerefeldberechnung. Aus fluggestützten Messungen werden Schwerestörungen berechnet, die der Bestimmung regionaler Geoidlösungen dienen. Zunächst wird das Messgerät und seine Funktionsweise erläutert. Anschließend werden drei Verfahren zur Geoidberechnung verglichen, die sich unterschiedlicher Konzepte bedienen: ein Integralverfahren mit abgewandeltem Stokes-Kern, die schwerpunktmäßig behandelte Methode der Multipole sowie das Kollokationsverfahren. Im Gegensatz zum Intergralverfahren arbeiten die Verfahren der Multipole sowie das der Kollokation ohne eine Feldfortsetzung nach unten. Im praktischen Teil der Arbeit werden die Verfahren auf den CHICAGO-Datensatz angewendet, der im Herbst 2002 in Südchile gemessen wurde. Die Genauigkeit sowohl der Messwerte als auch die der Geoidlösungen wird durch einen Vergleich mit unabhängigen Daten untersucht. Es stellt sich heraus, dass alle Verfahren im Rahmen der Genauigkeit zu akzeptablen Lösungen führen. Außerdem wird festgestellt, dass für niedrige Flughöhen der Einfluss der Feldfortsetzung vernachlässigt werden kann.

Description: In this thesis the subduction zone of the Central Andes is studied. The Andes have formed in a complex interplay of subduction related and tectonic processes. The Central Andes with the associated Altiplano-Puna high plateau constitute the second largest continental land-mass on earth, rivaled only by the Tibetan highland. Whereas in the case of the Himalayas , where two buoyant continental plates collide, crustal thickening and uplift is quite intuitive, processes leading to formation of a plateau above a subduction zone are puzzling.

Description: As observed on the Earth's surface, the magnetic field can be separated into three components: The "Main Field", the "Crustal Field" and the "External Magnetic Field". This work concentrates on the magnetospheric current systems, in order to correct the effect of large-scale magnetospheric current systems. Their exact knowledge is vital to improve the main field and secular variation models. Spherical harmonic analysis (SHA) is commonly used to describe the magnetic field. In SHA it is possible to distinguish between internal and external contributions to the Earth's magnetic field. The spherical harmonic coefficients describe dipolar, quadrupolar and higher parts in spherical coordinates. Here, CHAMP (CHAllenging Minisatellite Payload) measurements are used. Due to the inclination CHAMP is changing the orbit in local time. From time to time CHAMP is flying in resonance with the Earth's rotation, i.e. the satellite is flying over the same ground track after a couple of days. To model changes during a period of a few days these so called "repeat tracks" are very helpful for an improved main field/external field model. On the Earth's surface the magnetic effect of magnetospheric currents is often characterised by the DST-indix. In this study, it is explained how a possible constitution of the external sources of the geomagnetic field can look like and how the effect of these magnetospheric currents can be corrected in main field modelling.

Description: Die vorliegende Arbeit beschäftigt sich mit der kombinierten strukturgeologischen und magnetotellurischen Untersuchung eines Segmentes der ’West Fault’-Störung in den nordchilenischen Anden. Die West Fault ist ein Abschnitt des über 2000 km langen Präkordilleren-Störungssystem, welches im Zusammenhang mit der Subduktion vor der südamerikanischenWestküste entstanden ist. Die Aktivität dieses Störungssystems reichte vom Eozän bis in das Quartär. Der Verlauf der West Fault ist im Untersuchungsgebiet (22° 04’ S, 68° 53’W) an der Oberfläche klar definiert und weist über viele zehner Kilometer eine konstante Streichrichtung auf. Die Aufschlussbedingungen und die Morphologie des Arbeitsgebietes sind ideal für kombinierte Untersuchungen der störungsbezogenen Deformation und der elektrischen Leitfähigkeit des Untergrundes mit Hilfe magnetotellurischer Experimente (MT) und der erdmagnetischen Tiefensondierung (GDS). Ziel der Untersuchungen war es, eine mögliche Korrelation der beiden Meßmethoden herauszuarbeiten, und die interne Störungsarchitektur der West Fault umfassend zu beschreiben.

Description: In Südostalaska wird eine relative Meeresspiegelabsenkung von bis zu 4 cm/ a beobachtet. Da dieses Gebiet während der letzten Kaltperiode durch das Kordillerische Eisschild bedeckt war und noch heute von Vergletscherung geprägt ist, liegt die Vermutung nahe, daß die Meeresspiegeländerungen zumindest teilweise durch isostatische Ausgleichsvorgänge hervorgerufen werden. Um diese Hypothese zu prüfen, werden für dieses Gebiet eislastinduzierte Vertikalbewegungen und Geoidänderungen mit Hilfe viskoelastischer Erdmodelle berechnet. Insbesondere werden sechs siebenschichtige Erdmodelle verwendet, die unterschiedliche Viskostitätsprofile berücksichtigen und die Bandbreite der plausiblen Lithosphärenmächtigkeiten abdecken. Das globale Lastmodell ICE-3G wird erweitert und das regionale Lastmodell AL-1 entwickelt, welches die rezente Vergletscherung Südostalaskas berücksichtigt. Weiterhin werden die Ozeane als Last einbezogen. Ein Vergleich der berechneten mit den beobachteten Meeresspiegeländerungen zeigt, daß die Beobachtungen nur zu einen geringen Anteil von wenigen Millimetern pro Jahr durch Isostasie erklärt werden können.

Description: The Eifel is the youngest volcanic area of Central Europe. The last eruption occurred approximately 11000 years ago. Little is known about the deep origin and the mechanism responsible for the Eifel volcanic activity. Earthquake activity indicates that the Eifel is one of the most geodynamically active areas of Central Europe. In this work the receiver function method is used to investigate the upper mantle structure beneath the Eifel. Data from 96 teleseismic events (mb 〉 5.2) that were recorded by both permanent stations and a temporary network of 33 broadband and 129 short period stations had been analyzed. The temporary network was operating from November 1997 till June 1998 and covered an area of approximately 400x250 km^2 centered on the Eifel volcanic fields. The receiver function analysis reveals a clear image of the Moho and the mantle discontinuities at 410 km and 660 km depth. Average Moho depth is approximately 30 km and it shows little variation over the extent of the network. The observed variations of converted waveforms are possibly caused by lateral variations in crustal structure, which could not resolved by it receiver functions}. Inversions of data and migrated it receiver functions} from stations of the central Eifel array suggest that a low velocity zone is present at about 60 to 90 km depth in the western Eifel region. There are also indications for a high velocity zone around 200 km depth, perhaps caused by dehydration of the rising plume material. The results suggest that P-to-S conversions from the 410-km discontinuity arrive later than in the IASP91 reference model. The migrated data show a depression of the 410 km discontinuity of about 20 km, which correspond to an increase of temperature of about 140° Celsius. The 660 km discontinuity seems to be unaffected. This indicates that no mantel material rises up from directly below the 660 km discontinuity in the Eifel region or the Eifel-Plume has its origin within the transition zone.

Description: The report describes the main results of investigations performed in 2001 year in framework of a research contract between GeoForschungsZentrum Potsdam (GFZ) and the Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Moscow (IRE).

Description: Der Scientific Technical Report (STR) 03/08 ist die teilweise überarbeitete Diplomarbeit des Autors, welche im November 2002 am Lehrstuhl für Astronomie des Instituts für Planetare Geodäsie der Fakultät Forst-, Geo- und Hydrowissenschaften an der Technischen Universität Dresden eingereicht wurde.

Description: In the present thesis, interactions of kimberlites and lamproites as well as their constituent minerals with fluids are discussed based on noble gas compositions. The samples originate from the eastern Baltic Shield, more specifically from the Kola craton (Poria Guba and Kandalaksha) and the Karelia craton (Kostamuksha). Gas was extracted by stepwise heating and crushing from 23 whole rock samples and 15 mineral separates. These two techniques allow differential extraction of gas from fluid inclusions (crushing technique) and from the bulk sample (stepwise heating).

Description: After a gap of nearly two decades since the Magsat mission in 1980, the dedicated low-orbit potential field mission CHAMP is now in the third of its seven year mission. Already, the new magnetic total intensity and vector data have yielded maps of the global crustal field of unprecedented accuracy and resolution. Here, we assess the value of these maps to infer deep crustal structure of regions overlain by younger cover. A GIS based modelling technique has been developed to model the various geological units of the continents starting from the geological map of the world. Depending upon the known rock types of the region, they are assigned a standard susceptibility value and using the global seismic crustal structure, a vertically integrated susceptibility (VIS) model is computed at each point of the region. Starting with this initial VIS model, the vertical field anomaly is computed at a satellite altitude of 400 km and compared with the corresponding CHAMP vertical field anomaly map. The first comparison is carried out against a model using the lateral extent of a cratonic region as given by published tectonic maps. In the subsequent modelling step, depending upon the extent of the observed anomaly pattern of that region, the surface geology is extended beneath the sediments until the recomputed map fits the observed magnetic anomaly map. Here, we focus on modelling results for the selected few provinces of the world where the initial model does not agree with the observed anomaly map. Similar modelling of CHAMP satellite magnetic anomalies can constrain the subsurface structure hidden by Phanerozoic cover in many parts of the world.

Description: Die südlichen Anden sind Teil des aktiven Kontinentalrandes von Südamerika, der durch eine Kombination subduktionsgebundener Prozesse gebildet wurde. Die andine Gebirgskette erstreckt sich über den gesamten südamerikanischen Kontinent, variiert jedoch merklich in Höhe und Krustenmächtigkeit. Während die Zentralen Anden, vor allem auch die tieferen Strukturen bis in den oberen Mantel, vergleichsweise gut erforscht sind , ist über den geophysikalischen Aufbau der südlichen Anden bisher relativ wenig bekannt. Aus diesem Grund wurde das seismische Experiment ISSA2000 in den südlichen Anden durchgeführt. In dieser Arbeit wurde mithilfe der Methode der lokalen Erdbebentomographie ein 3-D Modell der seismischen Geschwindigkeitstruktur erstellt. Die gleichzeitig durchgeführte Lokalisierung der registrierten Erdbeben, ergibt darüberhinaus ein detailliertes Bild der Verteilung der Seismizität im Untersuchungsgebiet. Im Rahmen des ISSA2000-Experimentes wurde ein seismologisches Netzwerk mit 62 Seismographen betrieben, das die Subduktionszone von der Küste bis in den backarc zwischen 36° und 40°S überdeckt. Die Hypozentren der 440 lokalen Erdbeben zeigen eine ~30° geneigte Wadati-Benioff-Zone mit kontinuierlicher Seismizität bis in 120km Tiefe, die vereinzelt bis in 200km Tiefe zu beobachten ist. Sowohl die generell geringe Seismizität im Untersuchungsgebiet als auch die geringe Tiefenerstreckung der Wadati-Benioff-Zone u.a. im Vergleich zu den Zentralen Anden sowie die Konzentration der mitteltiefen Erdbeben in 60km Tiefe, spiegeln wahrscheinlich den Einfluß des jungen Alters und des damit verbundenen hohen thermischen Zustandes der Nazca-Platte auf das Subduktionsregime wider. Das tomographische Vp Modell zeigt zum ersten Mal die Geschwindigkeitsstruktur der südlichen Anden bis in eine Tiefe von 100km. Die Nazca-Platte ist durch die Lage der Erdbeben definiert und durch hohe Vp Geschwindigkeiten gekennzeichnet . Die durchschnittlichen Geschwindigkeiten in der kontinentalen Kruste sind im gesamten Vp Modell relativ hoch . Die tieferliegende Struktur kann in drei Gebiete unterteilt werden. Erniedrigte Vp Geschwindigkeiten in 30-50km Tiefe unterhalb der Küstenkordillere und oberhalb der abtauchenden Platte deuten eine mögliche Hydratisierung und Serpentinisierung des kontinentalen Mantelkeils an. Die Konzentration der Erdbeben in 60km Tiefe, die auf Dehydratisierungsprozesse innerhalb der subduzierten ozeanischen Lithosphäre zurückzuführen ist, könnte mit der beobachteten Geschwindigkeitsanomalie verbunden sein. Der Bereich unterhalb des Längstals ist von einer markanten Anomalie erhöhter Vp Geschwindigkeiten geprägt, die das gesamte Untersuchungsgebiet von N nach S durchzieht. Mantelgeschwindigkeiten werden hier ab 40km Tiefe erreicht. Weiter nach Osten nimmt die Krustenmächtigkeit zu und erreicht 50-55km unterhalb der Hauptkordillere und des aktiven vulkanischen Bogens. Geringe Geschwindigkeiten, ein erhöhtes Vp/Vs Verhältnis und die sich durch die Spektralanalyse andeutende Zone erhöhter seismischer Dämpfung könnte auf das Vorhandensein partieller Schmelzen und deren mögliche Anlagerung unterhalb der Kruste hindeuten.

Description: Diese Arbeit beschäftigt sich vor allem mit einem neuen Verfahren zur Abbildung von Leitfähigkeitsstrukturen. Mit der Propagation Number Analysis (PNA), die auf einen mathematischen Formalismus von Reilly [1979] zurück geht und die im Rahmen dieser Arbeit in einen physikalischen Kontext dargestellt wird, ist es möglich, die gesamte Tensor- Information in eine Widerstandsellipse zu transformieren. Sie gibt im übertragenen Sinn die Vorzugsrichtung der Ströme an und liefert somit ein Abbild der Leitfähigkeitsverteilung. Die graphische Präsentation fand bislang für transiente elektromagnetische Messungen Verwendung [Caldwell & Bibby, 1998], um einen wahren Widerstandstensor darzustellen. Die Widerstandsellipsen ergeben aufgrund von Geometrie und Farbkodierung flächenhaft ein Bild, in dem leitfähige Strukturen auch ohne Kenntnisse der MTTheorie erkennbar sind. Die dadurch gewonnenen Informationen lassen sich direkt mit der Geologie vergleichen oder für eine Modellierung nutzen.

Description: The Dead Sea Transform (DST) is a prominent shear zone in the Middle East. It separates the Arabian plate from the Sinai microplate and stretches from the Red Sea rift in the south via the Dead Sea to the Taurus-Zagros collision zone in the north. Formed in the Miocene »17 Ma ago and related to the breakup of the Afro-Arabian continent, the DST accommodates the left-lateral movement between the two plates. The study area is located in the Arava Valley between the Dead Sea and the Red Sea, centered across the Arava Fault (AF), which constitutes the major branch of the transform in this region. A set of seismic experiments comprising controlled sources, linear profiles across the fault, and specifically designed receiver arrays reveals the subsurface structure in the vicinity of the AF and of the fault zone itself down to about 3–4 km depth. A tomographically determined seismic P velocity model shows a pronounced velocity contrast near the fault with lower velocities on the western side than east of it. Additionally, S waves from local earthquakes provide an average P -to-S velocity ratio in the study area, and there are indications for a variations across the fault. High-resolution tomographic velocity sections and seismic reflection profiles confirm the surface trace of the AF, and observed features correlate well with fault-related geological observations. Coincident electrical resistivity sections from magnetotelluric measurements across the AF show a conductive layer west of the fault, resistive regions east of it, and a marked contrast near the trace of the AF, which seems to act as an impermeable barrier for fluid flow. The correlation of seismic velocities and electrical resistivities lead to a characterisation of subsurface lithologies from their physical properties. Whereas the western side of the fault is characterised by a layered structure, the eastern side is rather uniform. The vertical boundary between the western and the eastern units seems to be offset to the east of the AF surface trace. A modelling of fault-zone reflected waves indicates that the boundary between low and high velocities is possibly rather sharp but exhibits a rough surface on the length scale a few hundreds of metres. This gives rise to scattering of seismic waves at this boundary. The imaging (migration) method used is based on array beamforming and coherency analysis of P -to-P scattered seismic phases. Careful assessment of the resolution ensures reliable imaging results. The western low velocities correspond to the young sedimentary fill in the Arava Valley, and the high velocities in the east reflect mainly Precambrian igneous rocks. A 7 km long subvertical scattering zone (reflector) is offset about 1 km east of the AF surface trace and can be imaged from 1 km to about 4 km depth. The reflector marks the boundary between two lithological blocks juxtaposed most probably by displacement along the DST. This interpretation as a lithological boundary is supported by the combined seismic and magnetotelluric analysis. The boundary may be a strand of the AF, which is offset from the current, recently active surface trace. The total slip of the DST may be distributed spatially and in time over these two strands and possibly other faults in the area.

Description: Ein transversales Störungssystem im Nahen Osten, die Dead Sea Transform (DST), trennt die Arabische Platte von der Sinai-Mikroplatte und erstreckt sich von Süden nach Norden vom Extensionsgebiet im Roten Meer über das Tote Meer bis zur Taurus-Zagros Kollisionszone. Die sinistrale DST bildete sich im Miozän vor »17 Ma und steht mit dem Aufbrechen des Afro-Arabischen Kontinents in Verbindung. Das Untersuchungsgebiet liegt im Arava Tal zwischen Totem und Rotem Meer, mittig über der Arava Störung (Arava Fault, AF), die hier den Hauptast der DST bildet. Eine Reihe seismischer Experimente, aufgebaut aus künstlichen Quellen, linearen Profilen über die Störung und entsprechend entworfenen Empfänger-Arrays, zeigt die Untergrundstruktur in der Umgebung der AF und der Verwerfungszone selbst bis in eine Tiefe von 3–4 km. Ein tomographisch bestimmtes Modell der seismischen Geschwindigkeiten von P-Wellen zeigt einen starken Kontrast nahe der AF mit niedrigeren Geschwindigkeiten auf der westlichen Seite als im Osten. Scherwellen lokaler Erdbeben liefern ein mittleres P -zu-S Geschwindigkeitsverhältnis und es gibt Anzeichen für Änderungen über die Störung hinweg. Hoch aufgelöste tomographische Geschwindigkeitsmodelle bestätigen der Verlauf der AF und stimmen gut mit der Oberflächengeologie überein. Modelle des elektrischen Widerstands aus magnetotellurischen Messungen im selben Gebiet zeigen eine leitfähige Schicht westlich der AF, schlecht leitendes Material östlich davon und einen starken Kontrast nahe der AF, die den Fluss von Fluiden von einer Seite zur anderen zu verhindern scheint. Die Korrelation seismischer Geschwindigkeiten und elektrischer Widerstände erlaubt eine Charakterisierung verschiedener Lithologien im Untergrund aus deren physikalischen Eigenschaften. Die westliche Seite lässt sich durch eine geschichtete Struktur beschreiben, wogegen die östliche Seite eher einheitlich erscheint. Die senkrechte Grenze zwischen den westlichen Einheiten und der östlichen scheint gegenüber der Oberflächenausprägung der AF nach Osten verschoben zu sein. Eine Modellierung von seismischen Reflexionen an einer Störung deutet an, dass die Grenze zwischen niedrigen und hohen Geschwindigkeiten eher scharf ist, sich aber durch eine raue Oberfläche auf der Längenskala einiger hundert Meter auszeichnen kann, was die Streuung seismischer Wellen begünstigte. Das verwendete Abbildungsverfahren (Migrationsverfahren) für seismische Streukörper basiert auf Array Beamforming und der Kohärenzanalyse P -zu-P gestreuter seismischer Phasen. Eine sorgfältige Bestimmung der Auflösung sichert zuverlässige Abbildungsergebnisse. Die niedrigen Geschwindigkeiten im Westen entsprechen der jungen sedimentären Füllung im Arava Tal, und die hohen Geschwindigkeiten stehen mit den dortigen präkambrischen Magmatiten in Verbindung. Eine 7 km lange Zone seismischer Streuung (Reflektor) ist gegenüber der an der Oberfläche sichtbaren AF um 1 km nach Osten verschoben und lässt sich im Tiefenbereich von 1 km bis 4 km abbilden. Dieser Reflektor markiert die Grenze zwischen zwei lithologischen Blöcken, die vermutlich wegen des horizontalen Versatzes entlang der DST nebeneinander zu liegen kamen. Diese Interpretation als lithologische Grenze wird durch die gemeinsame Auswertung der seismischen und magnetotellurischen Modelle gestützt. Die Grenze ist möglicherweise ein Ast der AF, der versetzt gegenüber des heutigen, aktiven Asts verläuft. Der Gesamtversatz der DST könnte räumlich und zeitlich auf diese beiden Äste und möglicherweise auch auf andere Störungen in dem Gebiet verteilt sein.

Description: Der vorliegende Report fasst die wissenschaftlichen und technischen Arbeiten zur Steigerung der Produktivität von Thermalwasser in der Geothermie-Forschungsbohrung Groß Schönebeck 3/90 zusammen, die von 2002 bis 2004 durchgeführt wurden. Das Ziel des Projektes ist die Erschließung von heißen Wässern in tiefen Speichergesteinen, die sich zur Erzeugung von elektrischem Strom eignen. Dies erfordert die Bereitstellung einer kontinuierlichen Förderung heißer Tiefenwässer mit Temperaturen 〉 150 °C und Fließraten 〉 50 m³/h. In Tiefen mit Mindesttemperaturen um 150 °C ist die natürliche Permeabilität (Durchlässigkeit) der Gesteine jedoch nicht ausreichend. Die Gesteine müssen stimuliert werden, d. h. zu vorhandenen Rissen werden zusätzliche künstlich erzeugt, damit das Wasser ungehindert zirkulieren kann. Bereits vorliegende Erkenntnisse zur Erschließung und Charakterisierung der in weiten Regionen des Norddeutschen Sedimentbeckens in Tiefen von etwa 4000 bis 5000 Metern verbreiteten Speichertypen basieren größtenteils auf Erfahrungen der Erdöl- und Erdgasindustrie. Für die geothermische Nutzung sind diese jedoch nur eingeschränkt anwendbar, da bei der Erschließung von Kohlenwasserstoffen schon kleine Fließraten genügen. Daher liegt der Schlüssel zum Durchbruch der Geothermie in der Entwicklung effektiver Stimulationstechniken zur gezielten Produktivitätssteigerung geothermischer Reservoire. Die Geothermiebohrung Groß Schönebeck schließt geothermisch relevante Horizonte des Norddeutschen Beckens zwischen 3900 m und 4300 m in einem Temperaturniveau von etwa 150 °C auf. Diese Bohrung bietet derzeit die einzigartige Möglichkeit, die geothermische Nutzbarkeit unterschiedlicher Gesteinsformationen des Rotliegenden vertiefend zu untersuchen: die Vulkanite an der Basis und den darüber liegenden Sandstein. Experimente zur Erhöhung der Zuflussrate von heißen Wässern aus Sandsteinformationen durch hydraulische Stimulation konnten bereits erfolgreich durchgeführt werden (siehe Berichte zu den Projekten BEO 0327063 und ZIP 0327063C). Die erzielten Fließraten reichten jedoch für eine wirtschaftliche Elektrizitätserzeugung noch nicht aus. Daher wurden die Sandsteinformationen gemeinsam mit darunter liegenden Vulkaniten durch neu konzipierte Stimulationsverfahren erschlossen. Die angewendeten Methoden gleichen den vorhergehenden Projekten, wo durch hydraulisches Pumpen zusätzliche Risse im Gestein geschaffen werden. Bei entsprechender Produktionssteigerung von heißen Wässern aus dem Untergrund ist als anschließender Schritt eine zweite Bohrung geplant, mit der ein Förder- und Versenkkreislauf hergestellt werden kann. Ein geothermisches Kraftwerk vervollständigt die Installation. Da im Sedimentbecken von den Niederlanden über Norddeutschland bis nach Polen ähnliche geologische Verhältnisse vorliegen, haben die Ergebnisse aus der Bohrung Groß Schönebeck Pioniercharakter. Der Lern- und Anwendungseffekt aus den Experimenten kann unter diesem Aspekt als besonders beachtenswert eingestuft werden.

Description: For identification of the impact of salt-free and soured fluids injected for hydraulic stimulation on the about 4,000 m deep Rotliegend sandstones, cross-flow tests were carried out in combination with petrographic and fluid-chemical investigations. As a consequence of the swelling and the potential mobilisation of the clay minerals, a reduction of the permeability was expected. However, the test did not produce any significant change of the permeability for the cross-flow of differently conditioned waters under modified p/T conditions. But there could be proven the mobilisation of heavy metals and the solution of carbonate cement. As these cement minerals form a small fraction only in the total rock and due to their uneven distribution, no damage of the aquifer has to be expected. A local transport of finest particles could be observed which is probably connected with the carbonate solution. In case of suddenly increasing pore pressures, there is a risk of particle discharge, so that damaging of the pore reservoir cannot be excluded due to this small-scale transport of particles.

Description: The work contained in this thesis considers deformations of the Earth, which are produced by the loads of the last ice-age glacial sheets. The forces the Earth sets against the surface loads are the buoyancy force of the Earth's mantle and the opposing force by the elastic flexure of the lithosphere. Because the time scale of the ice-age of some 100,000 years is short with respect to geological time scales, the viscoelastic behaviour of the Earth has to be considered. Viscoelasticity results in a retarded response of the Earth, which is observed as postglacial uplift in previously glaciated regions, 8,000 years after deglaciation. To model the buoyancy of the Earth's mantle, often a viscous incompressible fluid of homogeneous density is assumed. More recent studies consider also compressibility of the mantle material, but keep the homogeneous density. This results in an inconsistent reference state, because the self compression due to hydrostatic pressure is neglected. These models are discussed here, and the problems are shown, which arise from the description of the field equations for a viscoelastic compressible gravitating continuum in a half-space geometry. The opposing force by the elastic flexure of the lithosphere is determined by the flexural rigidity of the lithospheric plate. If we consider viscoelastic layers in the lithosphere, the flexural rigidity is reduced. Therefore, the overall thickness of a viscoelastic layered lithosphere is much larger than its effective elastic thickness deduced from assuming one elastic plate. Consequently the effective elastic thickness looses its merit for assessing the lithosphere thickness. We show, how strong effective elastic thickness and lithosphere thickness may differ, in which way the viscoelastic structure of the Earth influences this difference for glacial loads and which consequences arise for the lithospheric stress state.

Description: Receiver function analysis is routinely used to isolates P-to-S converted waves from a complex of earthquake recordings s as to explore crustal and upper mantle structures and to infer possible geodynamic processes within the Earth. In the last several years the number of deployments of portable seismic arrays has been greatly increased. The conventional receiver function method, which stacks receiver functions at a single station, is not suitable for such a large amount of data. In this thesis modifications of the receiver function method have been made. Techniques of reflection seismology have been introduced into the receiver function analysis. Modified receiver function method has been successfully applied to the seismological data acquired in Tibet and the Central Andes. In these two Earth"s largest and highest plateaus, data of many available seismic broadband and short-period experiments have been collected. In Tibet, data of the INDEPTH II and GEDEPTH I experiments in southern Tibet and the PASSCAL 91/92 experiment across the central Tibetan Plateau have been combined. A Total number of about 50 stations were distributed roughly in a NNE directed profile. More than 900 receiver functions have been obtained. In the Central Andes, more than 200 stations have been deployed within the experiments of PISCO, CINCA, ANCORP, PUNA and KDS of the project of the SFB 267, and the BANJO and SEDA broadband arrays of the PASSCAL experiments. More than 640 teleseismic receiver functions have been obtained. Results are summarized in the following. (1) Crustal thicknesses under the two plateaus are reliably determined by Teleseismic receiver functions. P-to-S converted waves at the Moho are clearly seen under the Tibetan plateau and under Central Andean plateau. In southern Tibet the Moho is 75-80 km deep. In northern Tibet it becomes shallower to a depth of 55-60 km. In the Central Andes, the continental Moho is 65-70 km deep beneath the Andean Plateau (it appears to be 15 km shallower beneath Puna than beneath Altiplano). The Moho abruptly reduces its depth beneath the eastern edge of the Eastern Cordillera (65-64.5°W) and remains 45-50 km depth in the Sub Andes. Further east there is another abrupt reduction of Moho depth between the Sub Andes and the Chaco Plain. The Moho is 30-35 km beneath the Chaco Plain. (2) Evidence of crustal-scale underthrusting is found in Tibet as well as in the Andes. The INDEPTH data clearly show an intra-crustal phase at a depth of 50-60 km in the southern Tibet. This conversion boundary is probably the evidence of the underthrust Indian crust. In the Andean data a more than 300 km west-dipping intra-crustal converter evidently marks the boundary of the underthrust Brazilian shield crust. This boundary exists across the entire Altiplano and Puna plateau from 20 km depth below the Eastern Cordillera to 40 km depth below the Western Cordillera and the Precordillera. In both plateaus, most of the thickened crust, if not all, can be attributed to the crustal-scale underthrusting. (3) Plate boundaries are found to a depth of about 250 km between the Indian and the Asian lithospheric mantle and to a depth of about 120 km between the Nazca plate and the South American plate. However, the nature of these boundaries is different. In the Central Andes, the plate boundary is interpreted as the oceanic Moho of the Nazca plate, above which a 10 km layer of oceanic crust with lower seismic velocity suggests that the gabbroic rocks do not completely transform to eclogite until a depth of 120 km. Most of the intermediate depth seismicity stops at the same depth, suggesting a relation with phase transformation. In Tibet the observed plate boundary of the two lithosperic mantles probably reflects the temperature difference between the two plates. The cold Indian mantle is subducted under the warm Asian mantle. The Temperature difference can be as high as 500.700 ° resulting in large seismic velocity contrast. (4) Interesting variations have been found in the upper mantle discontinuities which are related to the plate collision and subduction processes. In Tibet, the 410 km discontinuity is clearly seen in its globally average depth in the south, and is disturbed and becomes complicated in the north. The 660 km discontinuity is continuously displayed throughout the Tibetan profile. Similarly, in the Central Andes, the 410 km discontinuity is not imaged coherently, which is obviously attributed to the subduction complexity of the phase transformation of the mantle rocks. It is interesting to see that the 660 km discontinuity is depressed by about 30-40 km in the region of the cold Nazca slab, which corresponds to a temperature reduction of 300-600° within the slab.

Description: Der vorliegende Bericht fasst die Ergebnisse der in den Jahren 2000 und 2001 durchgeführten Arbeiten zur Aufwältigung, zum primären Test- und Messprogramm sowie zum Monitoring in der Geothermiebohrung Groß Schönebeck 3/90 zusammen. Mit Mitteln aus der Grundfinanzierung des GeoForschungsZentrums Potsdam wurde die Bohrung aufgewältigt und bis in eine Endteufe von 4294 m vertieft. Sie erschließt geothermisch interessante Horizonte des Norddeutschen Beckens in Tiefen zwischen ca. 3900 m und 4300 m bei einem Temperaturniveau von ca. 150°C. Dabei gewonnene Ergebnisse lassen sich auf ähnliche geologische Randbedingungen im Norddeutschen Becken übertragen. Dieses Sedimentbecken zieht sich von den Niederlanden über Norddeutschland bis nach Polen hin.

Description: A Databank was created using data from 25 local catalogues and 30 special studies of earthquakes in central, northern and northwestern Europe. Event types were discriminated, fake events and duplets eliminated, and different magnitudes and intensities converted to Mw. The conversions require the establishment of regression equations. The Catalogue contains tectonic events from the Databank within the area 44°N-72°N, 25°W-32°E and the time period 1300-1993 which have Mw magnitudes of 3.50 and larger. The area is covered by different polygons. Within each polygon only data from one or a small number of the local catalogues, supplemented by data from special studies, enter the Catalogue. If there are two or more such catalogues or studies providing a solution for an event, a priority algorithm selects one entry for the Catalogue. Then Mw is calculated from one of the magnitude types, or from macroseismic data, given by the selected entry according to another priority scheme. The origin time, location, Mw magnitude and reference are specified for each entry of the Catalogue. So is the epicentral intensity, I0, if provided by the original source. Following these criteria, a total of about 5,000 earthquakes constitute the Catalogue. Although originally derived for the purpose of seismic hazard calculation within GSHAP, the Catalogue provides a data base for many types of seismicity and seismic hazard studies.

Description: Dieser Report fasst Ergebnisse aus der Startphase des Projekts Nutzbarmachung klüftigporöser Speichergesteine zur abnehmernahen geothermischen Energiebereitstellung zusammen. Das Projekt wurde mit Förderung durch das BMBF (BEO 0327063B) in einer Vorphase 1998 und durch das BMWi (BEO 0327063) 1999 gestartet.

Description: Das Ziel dieser Arbeit ist es, die Mechanik im Bereich des forearcs der Makran Subduktionszone zu untersuchen. Zu diesem Zweck kommen drei verschiedene Simulationstechniken zum Einsatz. Dies sind die Finite und die Diskrete Elemente Methode als zwei numerische Verfahren, sowie analoge Sandexperimente. Durch die Kombination dieser drei Methoden, die sich ergänzende und vergleichende Ergebnisse liefern, wird ein umfassendes Bild der Deformations- und Massentransferprozesse des forearcs in Makran gewonnen. Zudem ermöglichen alle drei Verfahren die Untersuchung des Deformationsverhaltens in einem Material, welches einer Mohr-Coulomb Rheologie mit strain hardening/strain softening bzw. einem work hardening gehorcht.

Description: Deformation processes in the early deformation stages of thrusting in growing fold-and-thrust belts and the role of factors controlling and localizing the deformation are still not well understood. There are only few natural examples or experimental studies to allow the identification of factors controlling initial states of deformation. In particular, the spatial interactions in curved fold-and-thrust belts or in segments striking obliquely to the convergence direction are rarely systematically examined. The Boomerang Hills Region (BHR), located at the eastern flank of the Central Andes close to the axis of the Bolivian Orocline, is an appropriate area to study such problems. There, oblique contraction is caused by a south-dipping basement interacting with a WSW-ENE to SW-NE convergence direction. In order to infer the controlling factors of deformation, the structural pattern associated with the active development of a new thrust sheet and the structural history of the adjacent foreland was examined. The detailed spatial-temporal relationships of Andean and pre-Andean structures within the BHR were investigated using a dense network of 100 reflection-seismic profiles for subsurface interpretation and structural modeling. In addition, satellite images and drainage pattern were interpreted to infer neotectonic activity. Modeling techniques included cross section balancing for validation and quantification of geological processes, horizon unfolding for kinematical interpretation, and critical taper estimates to derive the possible dynamic status. Results show that the main factor controlling the evolution of the Boomerang Hills Thrust Unit and the eastern flank of the Bolivian Orocline are paleogeographic features. The crystalline basement of the BHR comprises an inherited structure of several syn- and antiforms. Some of these structures were partly reactivated as minor reverse faults with associated small folds in the sedimentary cover at an early stage of the Tertiary foreland basin evolution. Basement faulting is probably a result of spatial problems linked to the initiation of a foreland basin in a heterogeneous crust. WNW-ESE striking normal faults were active in the foreland of the BHR in the Late Tertiary and show maximum activity during the intermediate state of foreland basin sedimentation. Further to the north, closer to the Brazilian Craton, normal faults are presently active. Foreland extension sums to 1.1%-1.5% and results from minor flexural extension due to bending of the Brazilian Shield lithosphere through Andean orogenic loading. The southern part of the BHR is represented by a young, evolving thrust sheet. Two zones can be differentiated along the Andean deformation front: (1) a W-E to NW-SE-striking frontal segment of predominantly orthogonal shortening, comprising a thrust / anticline system and accommodating at least 1400- 2000 m horizontal shortening on the basal decollement ; (2) A WSW-ENE-striking lateral zone of oblique shortening comprised by a complex system of thin-skinned strike-slip faults and minor folds. The deformation front always follows a pronounced edge in the topography of the top basement surface close to the boundary of the Paleozoic basin. Usually, faults are located close to asperities in the top basement surface; fold axes trend parallel to the contours of basement depth. The orientation of the deformation front as well as the laterally varying structural style is the result of deformation localization and strain partitioning. Because of the impossibility to accommodate non-orthogonal contraction by oblique faulting close to the surface, strain partitioning must occur along the deformation front. Consequently, a N 35°E thrusting direction is divided into orthogonal and tangential components, both with respect to the orientation of the deformation front and to depth contours of the basement. The two components are accommodated by convergent and strike-slip structures, respectively, which join via a common detachment horizon. The Boomerang Hills Thrust Unit is affected by left-lateral shear as interpreted from the particle displacement field of an unfolded horizon. This shear is invoked by the spatially distributed accommodation of thrust movement along the obliquely striking deformation front. The N 35° thrusting direction of the Boomerang Hills Thrust Unit represents the orthogonal component of strain partitioning caused by the WNW-ESE orientation of the Subandean Zone with respect to a WSW-ENE convergence between the Andes and the Brazilian shield. The tangential component is compensated at the back of the Boomerang Hills Thrust Unit where a positive flower structure is present and strain partitioning is made possible via the detachment horizon. Critical taper analysis shows that thrusting on the south-dipping basement is possible without any substantial internal deformation due to the wedge shape of the sedimentary prism. Therefore, the most important factor controlling the localization of the deformation front is the loss of critical taper at a pronounced edge along the Paleozoic basin boundary. Secondary reasons for deformation localization are small asperities in/close to the top of the basement, e.g. small folds of the early foredeep evolution. Strain partitioning may also play a major role for the evolution of the eastern border of the Bolivian Orocline and in other curved fold-and-thrust belts as discussed for natural and experimental examples. Generally, orthogonal accreting segments evolve faster than obliquely orientated segments due to strain partitioning at the deformation front, hence leading to an increase in the curvature of the belt. Strain partitioning itself is caused by the orientation of the deformation front with respect to the shortening direction. Thus, factors controlling the localization of the deformation front, i.e. paleogeographic features, dominantly control the evolution of curved fold-and-thrust belts. For the eastern flank of the Bolivian Orocline it is postulated that an early Paleozoic rift basin exerts paleogeographic control on Andean deformation, leading to the WNW-ESE orientation of the Subandean Zone between the Chapare and Santa Cruz. Based on map interpretation it is suggested that (a) the previously assumed style of deformation using main thrusts is questionable for this segment of the Andes and (b) deformation involving basally accreting foredeep sediments has to be taken into account. Previously assumed estimates of shortening for the Chapare area in the northern limb of the Bolivian Orocline may therefore be significantly low.

Description: In this report we describe the new repeat station network, the measurements and some tests regarding the use of the variometer recordings for data processing, and we present the results of this latest German magnetic survey.

Description: Recently released global gravity field models generated solely from CHAMP and GRACE satellite observations allow with an unprecedented accuracy and resolution the recovery of the mean sea surface topography from the difference between an altimetry-based mean sea surface height model and the gravity model's derived geoid. Here the CHAMP EIGEN-2 gravity field model, and the first GFZ GRACE gravity model, EIGEN-GRACE01S, are used. The mean sea surface height model has been compiled from four years'; worth of TOPEX altimeter data. To evaluate the accuracy and resolution limits of the CHAMP and GRACE geoids for the envisaged application, a low pass filter in the spatial domain with different cut-off wavelengths has been applied to the geoid and sea surface data before subtraction. The minimum wavelength, where noisy and erroneous features in the recovered sea surface topography are minimised, can be interpreted as an indicator for the best suited common spatial resolution. The EIGEN-2 model's geoid has been tested to have a resolution of 1800 km, which corresponds to a truncation degree of l = 22 in terms of spherical harmonics. Using the EIGEN-GRACE01S model, the resolution could be extended to 1000 km (l = 40). These boundaries can be attributed to the geoid's error, exceeding 2 cm in case of the CHAMP model, and in case of the GRACE model to spurious systematic signals increasing with increasing spherical harmonic degree. The calculated sea surface topography models have been used to derive absolute geostrophic sea surface velocities. An error propagation shows that the requirement of 1 cm/s for geoid induced velocity errors is fulfilled at the given resolutions for all latitudes excluding a narrow equatorial band. Maximum geostrophic velocities are derived in the 1000 km-resolution model for the Kuroshio region with 40 cm/s, and for the Gulf Stream east off Cape Hatteras with 25 cm/s.

Description: Polar motion data is available from the mid-19th century to the present. Based on time series with a variety of sampling intervals (monthly, 0.05-year, 5-day and daily), we have separated the low-frequency terms by low-pass filtering and the Chandler and annual terms by recursive band-pass filtering of the pole coordinates. Using a simple unweighted least-squares fit to the filtered low-frequency terms, the linear trends of the rotation pole were estimated. Assessing the estimates based on intercomparisons, the most reliable trend estimate was found. Using a Fast Fourier Transform, we have computed the prograde, retrograde and total amplitude spectra of the low-frequency part of polar motion in order to reveal the long-periodic signals. The characteristics and time evolution of the Chandler and annual wobbles are described by changes in their parameters (radii, directions and period lengths) over one century.

Description: Die vorliegende Arbeit konzentriert sich auf die Rekonstruktion der geodynamischen Entwicklung des aktiven Plattenrandes von Kamchatka vom Paläozän bis heute. Die vorgestellte Kombination von klassischen strukturgeologischen Methoden und Geländebeobachtungen mit thermochronologischen Untersuchungen und Datierungen an Apatiten eignet sich dabei in besonderem Maße.

Description: This report describes the set-up, logistics and results of the CHICAGO (Chilean Coastal AeroGeophysical Observations) survey. It gives a short overview about the scientific intentions, detailed documentation of all technical aspects starting from the survey equipment via the aircraft installation to the GPS stations set-up and the experiences in flight. All processing results for the individual profiles are discussed in detail. Finally, the data is compared and combined with available recent marine gravity data and altimetry derived solutions.

Description: Während der letzten Jahre sind in Deutschland extreme Naturereignisse aufgetreten, die zu großen, teilweise gar verheerenden Schäden geführt haben. Die Aufarbeitung dieser Katastrophen hat gezeigt, dass Deutschland nicht genügend auf solche Extremsituationen vorbereitet ist. Notwendig ist ein intelligenter Umgang mit Naturgefahren, der sich auf wissenschaftlich fundierte Analysen und Methoden stützt. Dazu gehört, dass Risiken durch Naturgefahren in ihrer raum-zeitlichen Entwicklung und in ihrer Wechselwirkung mit anthropogenen Einflüssen identifiziert und quantifiziert werden, zuverlässige Vorhersage-, Frühwarn- und Informationssysteme zur Verfügung stehen und Vorsorgestrategien eingesetzt werden, die auf einer umfassenden, konsistenten und transparenten Risikobewertung basieren. Die Entwicklung und Bereitstellung solcher Methoden und Werkzeuge erfordern einerseits das Zusammenwirken der verschiedenen Wissenschaftsdisziplinen und andererseits den engen Austausch zwischen Wissenschaft und operativem Katastrophenmanagement.

Description: The LaCoste & Romberg gravity meter S124b and its associated system environment were installed and tested in conjunction with a strap-down gravity meter system (SAGS) of the Bayerische Akademie der Wissenschaften in Munich on a Cessna Grand Caravan of the DLR in Oberpfaffenhofen. This report describes the design and instrumentation of the aerogravimetry system, it documents the installation on the aircraft and it discusses some of the results of the test flights performed within AGFA (Airborne Gravity Flight Approach). Beyond the documentation of the system this report gives a short introduction to the basics of the instruments including a short theory of their operation and data processing. The intention is to give readers from disciplines other than aero-gravimetry and aero-altimetry a technical insight into how the system works and what it is capable of. This should help the reader to evaluate the systems usefulness in other geo-scientific projects. The experiences from the test flights are briefly summarized and an update of the current status and future plans for the individual instruments is given. The aerogravimetry system consists of two major instrument blocks: the gravimetry sensing system and the positioning system. The gravimetry sensors are the LaCoste & Romberg S124b and the SAGS-2.2 systems. The navigation block holds GPS receivers, an inertial navigation system and a laser altimeter. The aircraft used for the primary tests was a Cessna Grand Caravan of the DLR in Oberpfaffenhofen. It offers superb conditions for scientific installations and is widely used in geophysical exploration all over the world. The test flights were flown from Oberpfaffenhofen airport. One profile covers the Bavarian Alps to map short wavelength, topography induced gravity disturbances, and another flight crosses the Rhine Graben to map long wavelength structures of the deeper crust. The software for data processing for navigation, gravimetry and geoid calculations is briefly summarized.

Description: This study attemps to identify and quantify the parameters that control mass-transfer modes in brittle tectonically erosive and accretive forearc settings. Scaled analogue simulations, which are specifically designed for this task, are compared with the convergent Chilean Margin that demonstrates both of these mass-transfer modes. Analogue simulation of geodynamic processes requires granular materials (e. g. sand) that deforms similarly to typical crustal rocks. Accordingly, a parameter study is performed, which yields general insight in the basic mechanics of highly-idealised convergent sand wedges.

Description: The investigation of heat flow is one of the prerequisites for modeling the thermal structure of sedimentary basins and allows the determination of its geodynamic state as well as the composition and structure of the basement. Although maps of the surface heat flow in the Northeast German Basin are published, our knowledge of this parameter is rather flaw. With this work a well-founded determination and evaluation of heat flow in the NEGB are presented for the first time. Under conductive and stationary conditions heat-flow density is calculated as the product of temperature gradient of a depth interval and its representative thermal conductivity. Therefore, the thermal conductivity of the rocks must be known, and temperature measurements must be available. The surface heat flow then can be calculated adding to this q the amount of heat generated by the radiogenic elements of the overburden. Deep boreholes, drilled in the course of oil and natural gas exploration, particularly in the years 1962-1990, were used in this study for the determination of q. Due to the targets of drilling and coring the depth intervals examined were predominantly in Permian rocks . Laboratory-derived thermal conductivity was determined in 363 core samples in dry and saturated conditions. The variability of TC within the lithotypes is related to facies, cementation, and degree of diagenesis. Based on the TC of lithotypes, the TC value of formations was estimated taking into account the respective facies conditions in the particular borehole. The TC of lithotypes and formations have higher values than previously supposed and used in modelings of the NEGB. Heat production of rocks was determined on the one hand by direct measurement of the content of U, Th, and K in 52 rock samples and on the other hand indirectly by evaluating borehole measurements. In order to do so, total gamma-ray intensity logs recorded in older gamma units were converted to modern API units using an empirical equation: GR[APIc]= 4.95433 × GR[GEc] - 27.24. The A value for the entire sedimentary succession of the NEGB calculated from GR logs amounts to 1-6 µW/m3 . The determination of q is accomplished and described in detail for 13 borehole locations. Possible disturbances were considered, and different correction procedures were applied. The corrections comprise the in-situ temperature correction of TC measured under room conditions, the corrections of temperature disturbances caused by the drilling process, corrections of lateral heat refraction at salt structures, and corrections of palaeoclimatic effects. The determined q values show an uncertainty, which is assumed to be approximately 15% for all locations. The qs values range between 70-90 mW/m2 . It is shown that both, different magmatic successions at the basin basis and the different Mesozoic and Cenozoic deposits affect a differentiation of qs. The qs values of this study do not coincide with the distribution pattern of former qs maps. In order to investigate the thermal consequences of different assumptions of structure and composition of the crust and the lithosphere, 2D sections were modelled under steady-state conditions. Variable compositions of the crust and different thicknesses of the lithosphere could explain the determined qs values. It is assumed that the Pritzwalk gravity anomaly of dense rock with less heat production causes a negative thermal anomaly at the surface. Without a better knowledge of the deeper underground of the NEGB it cannot be estimated as to which parts the determined mean q depends on a high heat production of the crust or a high mantle heat flow. It also cannot be ascertained whether the assumption of a thermal stationary regime, which represents a substantial part of the computations, is justified for the NEGB.

Description: Compared to the Chandler and annual wobbles, the higher-frequency components of polar motion (PM) have substantially smaller amplitudes. Therefore, their study had to wait until higher-quality time series with high temporal resolution, as measured by space geodetic techniques, became available. Based on the combined Earth orientation series SPACE99 computed by the Jet Propulsion Laboratory (JPL) from 1976 to 2000 at daily intervals, we have separated the periodic PM terms by band-pass filtering and found that the persistence of oscillations becomes less with increasing frequency (H¨opfner 2001a, b). In order to quantify and better describe the parameter variability of these PM components over time, particularly of eight oscillations with periods ranging between about 650 and 45 days, we computed the radii, direction angles and period lengths from the periodic terms filtered out from the time series. The results clearly show the characteristics and time evolution of the periodic PM components that are important for geophysical interpretations.

Description: The Effect of the Geocentric Gravitational Constant on Scale: It is well known that the geocentric gravitational constant (GM) is a scaling factor for the reference frame realized by satellite techniques. One must be aware that its effects on the orbit and on the terrestrial reference frame (station positions) are different. The scale effect on restituted orbits is 1/3* (dGM/GM) (relative error of GM) for all kinds of satellites. But the effect on the terrestrial frame depends on the height of the satellites, on tracking techniques and on the solved for parameters. For ranging techniques such as SLR, the scale variation of the terrestrial frame is 1/3*(dGM/GM)*(rSat) / (rEarth), if the range biases are not solved for. For GPS the GM error is mostly absorbed by the clock estimates (or eliminated by the double differences), only the remaining few percents go into the scale of terrestrial reference frame. For instance if one is using a GM value of 3.986004418 1014 m3/s2 instead of 3.986004415 1014 m3/s2 (relative variation is 7.5 10-10) the scale variation of the terrestrial frame is only about 6 10-11. Physically, the error in the z-direction of the antenna phase center offsets on board GPS has nothing to do with GM. But its effect on the terrestrial reference frame is practically equivalent to an error in GM. For instance, if all GPS satellites have a 7.1 cm error in dz, the effect on the station position is equivalent to a relative error of 8 10-9 in GM (e.g. changing GM from 3.986004418 to 3.986004386 1014 m3/s2). Satellite Antenna Phase Center Offsets and Scale Errors in GPS Solutions: ITRF2000 solutions (see Lareg, 2001) have shown that there are ppb level scale differences between GPS and other techniques and among various GPS Analysis Centers. The trends of the scale differences reach 0.2 ppb per year. The uncertainties of the current available Earth’s gravitational constant could only cause less than 0.1 ppb scale error for GPS technique. On the other hand, the uncertainties in the satellite antenna phase center offsets could produce ppb level scale error. Various BLOCK types of GPS satellites have different phase center errors. The number of BLOCK IIR satellites increases from year to year. This could cause trend-like variations in the scale error. Beside station positions, satellite antenna phase center errors affect also the clock, Zenith Path Delay, and other solved for parameters perceptibly.

Description: Chandler and annual wobbles based on space-geodetic measurements: In this study, we examine the major components of polar motion, focusing on quantifying their temporal variability. In particular, by using the combined Earth orientation series SPACE99 computed by the Jet Propulsion Laboratory (JPL) from 1976 to 2000 at daily intervals, the Chandler and annual wobbles are separated by recursive band-pass filtering of the χ1- and χ2 -components. Then, for the trigonometric, exponential, and elliptic forms of representation, the parameters including their uncertainties are computed at epochs using quarterly sampling. The characteristics and temporal evolution of the wobbles are presented, as well as a summary of estimates of different parameters for four epochs.

Description: Polar motions with a half-Chandler period and less in their temporal variability: Our study focuses on the observed higher-frequency polar motions that are substantially smaller than the Chandler and annual wobbles. Here, the combined Earth orientation series SPACE99 from 1976 to 2000 with one-day sampling is used as input data, after removing the low-frequency, the Chandler and annual terms. We applied a data processing procedure including four steps, each computing the amplitude spectrum by a Fast Fourier Transform in order to reveal the periodic signals in the residual motions, and then separating their components from the residual time series by band-pass filtering. In particular, the oscillations have the following periods: Semi-Chandler and semi-annual periods and those of order four, three, two, and one and a half months, as well as quasi-biennial and 300-day periods. We show to what extent the observed polar motions are irregularly occurring. A very small polar motion signal with the period of one month is still found in the remaining motions.

Description: Hawaii gehört zu den bekanntesten Beispielen für Hotspot-Vulkanismus weltweit. Die von weiteren tektonischen Einflüssen isolierte Position inmitten des Pazifischen Ozeans macht Hawaii zu einem interessanten Untersuchungsobjekt auf dem Gebiet der Mantelplumes. Weder die Entstehungstiefe noch die genaue Lage des Plumeschlauches im Erdmantel sind bislang genau bekannt - Fragen, deren Beantwortung auch neue Erkenntnisse bezüglich der dynamischen Prozesse des Mantels, wie etwa der Konvektion, liefern könnte. In dieser Arbeit wurde die Methode der Receiver Functions angewendet, um die Strukturen bis in den obersten Teil des unteren Mantels unter Hawaii zu untersuchen. Zur Auswertung standen Daten von elf temporären Breitbandstationen auf den vier größten Hawaii-Inseln zur Verfügung, welche im Zeitraum von Juni bzw. November 1999 bis Mai 2001 kontinuierlich registrierten, sowie zusätzliche Daten permanenter Breitbandstationen. Die Untersuchung ergab eine Reihe von neuen Ergebnissen der seismischen Struktur in verschiedenen Tiefenbereichen. In Übereinstimmung mit früheren Studien konnte die Moho in Tiefen zwischen 12 - 17 km beobachtet werden. Im jüngeren Teil der Inselkette, von Big Island bis etwa Oahu, tritt zusätzlich eine sehr starke Konvertierte auf, die innerhalb der Kruste erzeugt wird und zum jüngeren Bereich hin systematisch früher auftritt. Deutlich ausgeprägt erscheint im Messgebiet die Lithosphären-Asthenosphären-Grenze. Der langfristige Einfluss des Plumes bewirkte eine Ausdünnung der Lithosphäre im älteren Teil der Inselkette. Innerhalb der Asthenosphäre wurde eine lokale Niedriggeschwindigkeitszone unterhalb von Big Island nachgewiesen, deren Ursprung ebenfalls mit dem Plume in Verbindung gebracht wird. Die Diskontinuitäten der Mantelübergangszone in 410 km und 660 km Tiefe konnten klar identifiziert werden. Stellenweise konnten außerdem konvertierte Phasen aus 520 km sowie aus größeren Tiefen beobachtet werden. Anhand der Ankunftszeiten der P410s und P660s konnte das Messgebiet in drei Regionen unterteilt werden: Der Südosten der Inselkette bis zur Mitte von Big Island zeigt keinerlei Einflüsse des Plumes, während der nordwestliche Teil auf reduzierte S-Wellengeschwindigkeiten im oberen Mantel schließen lässt. Südwestlich von Big Island jedoch weist eine deutliche Ausdünnung der Mantelübergangszone auf die Position des Plumes hin. Für dessen Kernbereich wurde ein Radius von etwa 120 km ermittelt.

Description: The Altiplano represents a key region of the Central Andes, where the interplay between faults and syn-tectonic sediments allow the reconstruction of the kinematic evolution of the Central Andean high plateau. This study aims, by the use of incrementally-balanced crosssections, interpretation of reflection-seismic profiles, 3D strain analysis, gravity data interpretation, isotopic-age dating, and surface observations, to reconstruct the geological and tectonic history of the Southern Altiplano at 21o S between the Eastern and the Western Cordillera. The Southern Altiplano is a complex intramontane basin with 6-8km Cenozoic fill. It can be structurally divided in three domains; the Eastern, Central, and Western Altiplano. 2D balanced cross-sections based on seismic-reflector analysis and field observations show that the Eastern Altiplano is the buried, thin-skinned deformation front of the western part of the Eastern Cordillera's bivergent thrust system. The 20-40° dipping, blind faults merge into a shallow, eastward-dipping detachment at 7-9km depth that continues into the Eastern Cordillera. The Central Altiplano forms a bivergent system with 30-90° dipping, basement-involving thrusts in the east, and fault-propagation folds in the west. The shallow, westward-dipping detachment lies at 9-10km depth and possibly continues into the Western Altiplano, which forms a separate bivergent thrust-system.The computer-aided (GeoSec and 2DMove), incremental restoration of the balanced crosssections of the Eastern and Central Altiplano, and preliminary line-length balancing of the Western Altiplano, yields 38km shortening due to folding and thrusting. 3D strain analysis of sandstone grain shapes reveals that an additional 7.7% of shortening was accumulated as ductile, micro-scale strain. This increases the total shortening in the entire cross-section of the Southern Altiplano at 21° S to 60km or 21%. In addition, I suggest that the contribution of outcrop-scale structures possibly accounts for another 20 km. 3D strain analysis further shows that the 7.7% of microscale strain were accompanied by 13% orogen-parallel extension. These shortening estimates more than double the published shortening values from the Altiplano. Crustal thickening and plateau uplift in the arc-backarc domain of the South American convergent margin took place during the Cenozoic. K-Ar and Ar-Ar age-dating on syn-tectonic sediments, together with seismic-sequence analysis, demonstrates that the Southern Altiplano structure formed during two independent compressional increments (Early Oligocene [〉27 Ma] and Middle/Late Miocene [17-8 Ma]), which were preceded by an Eocene/Oligocene extensional event that led to the formation of a half graben in the Central, and possibly a second in the Eastern Altiplano. Horizontal contraction of the Altiplano ended between 11-8 Ma, was indicated by the age of undeformed volcanic rocks. Detailed seismic analysis of single syn-tectonic basins combined with isotopic ages of syntectonic sediments, reveal a complex deformation history characterised by spatially and temporally irregular fault activation, which excludes the existence of large-scale eastward or westward propagating deformation during plateau formation. This diffuse pattern of deformation was characteristic for the entire plateau domain, i.e. from the western flank to the eastern edge of the Eastern Cordillera, during a first stage of plateau formation between 30 and 10 Ma. This possibly indicates that the plateau has remained flat since its formation and did not evolve from an initially doubly-vergent orogen. The syn-tectonic stratigraphic units of the Southern Altiplano domain overlie shallow marine, Late Cretaceous sediments that still form a sub-horizontal regional near sea level. This indicates that plateau surface-uplift in this part of the plateau was mainly achieved by sedimentary in fill of tectonically-controlled, internally-drained basins, and not by tectonic uplift. The tectonic evolution of the Southern Altiplano was largely accompanied by magmatic activity. An episode of strong volcanic activity affected the entire width of the Altiplano and adjacent parts of the Eastern Cordillera between 25-8 Ma. However, a causal relationship between magmatism and deformation could not be shown for the Southern Altiplano. Strong Oligocene/Miocene volcanic activity, together with the diffuse pattern of deformation, suggests that the formation of the Altiplano Plateau was initiated by magmatically-controlled thermal weakening of the crust, possibly as the result of the removal of the mantle lithosphere. At present, the Altiplano has a flat topography, high heat-flow, and is spatially related to a variety of geophysical anomalies that are interpreted as partial melting of the middle crust (20-40km depth). From this evidence, I propose that the process of plateau formation is still active.