Chromat-Gehalte in Holzaschen

Beim Verbrennen von Holz (Schnitzel, Pellets) zu Heizzwecken werden die im Holz vorhandenen Spuren von Chrom oxidiert und das so entstandene Chromat wird in der Holzasche passiv angereichert. Die Chromat-Gehalte verschiedener Aschen werden nasschemisch analysiert, und die Resultate werden mit den gesetzlichen Anforderungen für die Entsorgung von Abfällen verglichen. Weiter wird die heutige Entsorgungspraxis von Holzaschen beschrieben. Bedingung: Kommunikationsfreude im Gespräch mit Holzheizern

Kontakt: Franz Schenker  

Status: Offen

Professur: Extern

Oszillierende chemische Systeme

Oszillierende chemische Systeme regen dank den Erkenntnissen der Chaos-Theorie auch in der Geologie wieder zum denken an. Als Experiment für die Verwendung im Unterricht soll die Beloussov-Zhabotinsky-Reaktion im Labor durchgeführt und mit Video dokumentiert werden. Weiter sind konkrete geologische Phänomene aus der Geologie aufzulisten (inkl. Begründung), die möglicherweise auf oszilierende Ungleichgewichtsreaktionen zurückzuführen sind.Voraussetzungen: Pioniergeist sowie Freude an Laborchemie und Mathematik

Kontakt: Franz Schenker  

Status: Offen

Professur: Extern

Seesedimente als Archive natürlicher und anthropgen-induzierte Umweltveränderungen

Das Studium der Seesedimente erlaubt historische und prähistorische Zeitreihen von Oberflächenprozessen im See und im Einzugsgebiet, die häufig mit Naturgefahren in Verbindung stehen (Erdbeben, Bergstürze, Hangrustchungen, Tsunamis). Bachelorprojekte in Limnogeologie untersuchen mittels geophysikalischer, sedimentologischer und geochemischer Methoden den Untergrund der Seen im In- und Ausland. Interpretation dieser Daten rekonstruieren die vergangenen Umwelt- und Klimaveränderungen sowie die Abfolge, Prozesse und Auskwirkungen von Naturgefahren. Genauere Auskünfte über mögliche Projekte werden bei einem persönlichem Gespräch vermittelt.

Kontakt: Flavio Prof. Dr. Anselmetti   Adrian Dr. Gilli  

Status: Offen

Professur: Extern

Forensic Statistical Seismology: Searching for recent changes in the homogeneity of the Northern California Earthquake Catalog

The Northern California Earthquake Data Center recently introduced a new approach to compute the magnitudes of earthquakes recorded within the network. A similar change in southern California resulted in drastic changes in the homogeneity of reporting and earthquake scaling laws, with have substantial implications for seismic hazard assessment (Tormann et al., 2010). In this project, we will search for the telltale signatures of changes in the Northern California dataset, using the techniques already developed for Southern California.

Kontakt: Prof. Stefan Wiemer  

Status: Offen

Professur: SED

Analysis of topographic effects on ground motion

Theoretical studies based on numerical modelling have shown the strong influence of surface topography on seismic motion. However, such models are usually not able to explain observed seismograms. This is usually explained by unknown subsurface structure, which may together with the topography produce local resonances. Such resonances were identified at one permanent station of Swiss Seismological Service, which is located on a mountain cliff. As a high-quality broadband sensor is installed on the site for more than 10 years, it gives an unique opportunity to monitor temporal changes of the structure. The proposed work will focus on analysis of existing recordings of both earthquakes and ambient vibrations.

Kontakt: Dr. Jan Burjanek   Dr. Donat Fäh  

Status: Offen

Professur: SED

Soil-structure interaction from a building in a sedimentary basin

Structures like buildings are never perfectly embedded in the soil, resulting among other effects in the modification of the dynamic properties of the structure, and the re-emission of seismic waves from the building to the ground. These effects particularly appear for loose soils in a sedimentary basins. The project includes the study of these effects for a high-rise residential building that is suspected to radiate energy in the Rhone basin in Visp. In-situ tests will be performed in the structure and on the surrounding soil and the radiated energy will be studied at seismic stations of the Swiss Seismological Service. The effects induced by ambient vibrations and by earthquakes will be compared.

Kontakt: Dr. Clotaire Michel   Dr. Donat Fäh  

Status: Offen

Professur: SED

Identification of resonances in complex geological structures

Array measurements of ambient vibrations can be used to identify two-dimensional resonances in Alpine Valleys. Such resonances are of particular importance during damaging earthquakes, causing a dramatic increase in the amplitudes of strong ground motion. Recently new tools have been developed that have the potential to determine the frequencies of 2D resonances from passive seismic measurement at one station only. The proposed work should explore the usefulness and potential of this new technique, and compare it to results from array method, and finally apply it to different areas in the Valais.

Kontakt: Dr. Jan Burjanek   Dr. Donat Fäh  

Status: Offen

Professur: SED

Characterisation of soft surface layers through active excitation of higher modes Rayleigh waves

Shallow surface layers with loose sediments behave very unfavourable during strong earthquakes due to the large amplification of waves and non-linear behaviour such as liquefaction. Such layers are often difficult to identify, especially with passive single-station methods. Seismic waves trapped in such layers would carry information about the thickness and S-wave velocity in the layer. However the waves are often damped due to strong anelastic behaviour of the soils. Active excitation of the soft surface layers with a vibrator will therefore be used to excite higher modes Rayleigh waves, and to identify the ellipticity curves of these waves, allowing an estimate of thickness and velocity in the soft layers. The method will be tested and if successful applied to a target region of interest (City of Luzern or Visp).

Kontakt: Dr. Valerio Poggi   Dr. Donat Fäh  

Status: Offen

Professur: SED

Quantification of site amplification at K-Net and Kik-Net stations in Japan

A new method is applied to define a regional reference rock profile related to a regional ground motion prediction equation for Japan, and to combine average velocity at a site with the frequency-dependent amplification. The large Japanese dataset from the K-Net and Kik-Net is used. The final task is to develop a tool to predict amplification of seismic waves for specific sites that are characterized by the fundamental frequency of resonance of the soils, the polarisation between vertical and horizontal components, and information on the shear-wave velocity profile. The model is compared to a similar model developed for Switzerland using small earthquakes only.

Kontakt: Dr. Ben Edwards   Dr. Valerio Poggi   Dr. Donat Fäh  

Status: Offen

Professur: SED

First break tomography of seismic exploration data from the Okavango Delta Region in Botswana

The group of Applied and Environmental Geophysics at ETH Zurich will conduct a field campaign in the Okavango Delta in Botswana during January and February 2010. The aim of the campaign is to obtain information about the subsurface of the inland delta down to the bedrock in order to reconstruct its complex geological and hydrological history. A series of geophysical methods will be applied. One of them will be the refraction seismic method. The BSc thesis deals with the processing of a 2D seismic data set in order to obtain cross sections of the p-wave velocity distribution in the subsurface down to approximately 300 m, depending on the seismic wave attenuation in that area. The student will learn and deal with all the conventional processing steps necessary for a first break tomography study. First, the geometry of the seismic survey has to be included in the data. Second, first arrivals of every shot have to be identified and marked. Based on the arrival time of the first breaks and by inversion the p-wave velocity distribution along the survey line will be determined. An inversion code will be used which was developed in the Environmental- and Engineering Geophysics group at ETH Zurich and which is based on an Eikonal forward solver for the computation of travel times in non homogeneous media. The inversion code is ready to use. The BSc thesis will be concluded with an interpretation of the inverted velocity model with respect to the hydrology and geology of the Okavango delta region. A detailed literature study is required for the interpretational part of the thesis.

Kontakt: Dr. Lasse Rabenstein   Dr. Stefan Carpentier   Dr. Heinrich Horstmeyer  

Status: Offen

Professur: Green

Design of direct-current resistivity measurements for a field campaign in the Okavango Delta, Botswana

The group of Applied and Environmental Geophysics at ETH Zurich will conduct a field campaign in the Okavango Delta in Botswana during July and August 2010. One of the geophysical methods that is to be employed during the field campaign is the direct-current resistivity (DCR) method. Here, two pairs of electrodes are employed per measurements: with one pair, a constant current is fed into the subsurface; with the other pair, the resulting potential difference is measured. This potential difference changes according to the distribution of the electrical resistivity in the subsurface. The depth over which the measurements contain information can be increased by increasing the electrode separation. For the Botswana project, the desirable depth range of investigation is tens of metres down to 300m. The aim of the BSc project is to optimally design the layout of the DCR measurements. The procedure is as follows: 1) Synthetic DCR data are generated for pre-assumed models of the electrical resistivity distribution in the subsurface and for several classical DCR electrode layouts. The maximal electrode separations correspond to local conditions in the measurement area. 2) The synthetic data are contaminated with Gaussian white noise of a pre-supposed intensity. 3) The synthetic data are inverted to distributions of electrical resistivity in the subsurface. 4) Simple comparisons with the originally pre-assumed resistivity distribution allow to assess the potential depth range of investigation that can be obtained with a certain set of DCR measurements.

Kontakt: Dr. Thomas Kalscheuer   Dr. Joel Podgorski  

Status: Offen

Professur: Green

Application of Ground Penetrating Radar on glaciers

Ground Penetrating Radar (GPR) is a potentially powerful tool for characterizing glaciers. It allows ice thicknesses and possibly internal structures to be delineated. In the framework of this project extensive measurements with different GPR systems and different antenna types will be performed. It should be determined, which configuration provides the best results for a particular scenario. Data analysis will be performed with Matlab. The conclusions of this thesis project will be highly relevant for future glaciological projects that include GPR measurements. Data will be collected on alpine glaciers. Skiing skills and preferably a little bit of alpine ski touring experience is required.

Kontakt: Dr. Hansruedi Maurer   Dr. Andreas Bauder  

Status: Offen

Professur: Green

Untersuchungen zur einaxialen Druckfestigkeit von Opalinuston in Abhängigkeit der Saugspannung

Von vielen Tongesteinen ist bekannt, dass die Wassersättigung eine bedeutende Auswirkung auf die Druckfestigkeit hat. Dies liegt darin begründet, dass bei Absättigung und Gaseintritt (Luft) hohe je nach Porengrosse Saugspannungen entstehen, deren mechanische Wirkung ähnlich dem eines Manteldrucks zu bewerten ist. Dieser Prozess ist sowohl für das Kurzzeit- als auch Langzeitverhalten eines Endlagers für radioaktive Abfälle von Bedeutung. Durch gezielte Konditionierung von Probenmaterial in einem Exsikkator sollen vordefinierte Saugspannungen künstlich erzeugt werden. Die so vorbereiteten Proben werden anschliessend für einaxiale Druckversuche verwendet, wobei sowohl die axiale und radiale Dehnungen und die mikro-akustische Aktivität erfasst werden soll. Ziel der Arbeit ist Zusammenhänge zwischen Saugspannung, volumetrischen Verhalten und Spitzenfestigkeit zu quantifizieren.

Kontakt: Dr. Florian Amann   Reto Thöny  

Status: Offen

Professur: Löw

Ingenieurgeologische Analyse der Hanginstabilität Kilchenstock, Kanton Glarus

Der Kilchenstock (1800m) im Kanton Glarus stellt seit etwa 1900 aufgrund häufiger Murgänge eine ständige Bedrohung der Gemeinde Linthtal dar. Diese Bedrohung führte bereits zur Evakuierung der ansässigen Bevölkerung und der Errichtung von Schutzbauwerken am Hangfuss. Auf Anraten des Geologen Albert Heim wurde im Jahr 1930 Linthal evakuiert, da die Gipfelpartie des Kilchenstock zu versagen drohte. Der erwartete Bergsturz blieb jedoch aus. Besonders die Beobachtung von Geologen in jüngster Zeit zeigen jedoch, dass bis heute Evidenzen bestehen, die ein Versagen der Gipfelpartie als wahrscheinlich bezeichnen lassen. Im Rahmen der Arbeit soll die Geschichte der Absturzszenarien zusammengestellt, eine geologisch-geotechnische Karte der Instabilität erstellt und ein grundlegendes Überwachungsprogramm erarbeitet werden. Auf Grundlage dieser Daten sollen Versagenszenarien erarbeitet und diskutiert werden. Die Arbeit soll im Rahmen einer Masterarbeit wieder aufgegriffen und vertieft werden.

Kontakt: Dr. Florian Amann   Dr. Ömer Ündül  

Status: Offen

Professur: Löw

Untersuchung der Hydrogeologie und Hydrochemie der Badquelle Oberbergen/ BRD

Diese Arbeit umfasst neben einer Abklärung der hydrogeologischen Situation (Literatur- und ev. eigene Beobachtungen) auch die Bestimmung der chemischen Beschaffenheit, sowie die Messung der Fluoreszenz und der Radon Konzentration des Wassers.Die natürlichen Schwankungen der Fluoreszenz des Wassers und der Radon Konzentration sollen dabei auch mit der vorkommenden seismischen Aktivität verglichen werden.

Kontakt: Dr. Fanny Leuenberger   PD Dr. Werner Balderer  

Status: Offen

Professur: Löw

Untersuchung der Thermalquelle Pfäfers/Bad Ragaz in der Taminaschlucht

Diese Thermalquelle weist eine sehr konstante Austrittstemperatur von rund 36 °C, sowie eine sehr konstante chemische Zusammensetzung auf. Ziel dieser Arbeit: Diese Arbeit umfasst neben einer Abklärung der hydrogeologischen Situation (Literatur- und ev. eigene Beobachtungen), die Bestimmung der chemischen Beschaffenheit, sowie die Messung der Fluoreszenz und der Radon Konzentration des Wassers. Die natürlichen Schwankungen der Fluoreszenz des Wassers und der Radon Konzentration sollen dabei auch mit der vorkommenden seismischen Aktivität verglichen werden.

Kontakt: Dr. Fanny Leuenberger   PD Dr. Werner Balderer  

Status: Offen

Professur: Löw

New computer-based techniques for automatic model parameter estimation

Together with the Institute for Computer Science/ETH, promising new optimization techniques from the field of soft computing will be examined for their applicability to inverse modeling problems in hydrogeology. Real-site oriented test cases of numerical soil and aquifer models will be set up, and selected parameters will be fitted to measured or simulated reference values. The highly interdisciplinary work requires a student with strong skills in programming. No specific knowledge on modeling and optimization procedures is needed, but the candidate has to be open for learning the applied procedures. The overall goal is to identify efficient new variants of evolutionary algorithms for (hydro)geological parameter estimation. This means that several different implementations will be tested, and interpretation of the different results has to be well planned. A personal tutorial for getting into the topic will be provided at the beginning and tight supervision is guaranteed.

Kontakt: Dr. Peter Bayer  

Status: Offen

Professur: Löw

New computer-based techniques for automatic model parameter estimation

Together with the Institute for Computer Science/ETH, promising new optimization techniques from the field of soft computing will be examined for their applicability to inverse modeling problems in hydrogeology. Real-site oriented test cases of numerical soil and aquifer models will be set up, and selected parameters will be fitted to measured or simulated reference values. The highly interdisciplinary work requires a student with strong skills in programming. No specific knowledge on modeling and optimization procedures is needed, but the candidate has to be open for learning the applied procedures. The overall goal is to identify efficient new variants of evolutionary algorithms for (hydro)geological parameter estimation. This means that several different implementations will be tested, and interpretation of the different results has to be well planned. A personal tutorial for getting into the topic will be provided at the beginning and tight supervision is guaranteed.

Kontakt: Dr. Peter Bayer  

Status: Offen

Professur: Löw

Examination of the shallow subsurface temperature distribution in Zürich

The focus of this thesis is set on regional anthropogenic effects of geothermal energy use and waste heat injection in the shallow geological underground of Zürich. In the big cities of Europe, North America and Asia meanwhile serious artificial temperature anomalies evolve in the underlying aquifers. Also the geothermal energy use in the area of Zürich is intense. Has this also generated such ''subsurface climate chang''? This will be subject to this thesis. The work will cover collection of available studies, raw data material and reports on spatially and temporally resolved temperature measurements of the area of Zürich city. Additionally, field temperature measurements will be conducted at selected pumping and observation wells. The heterogeneous data sets will be filtered and categorized with respect to measurement dates, depths and accuracy. Finally a 3D isotherm map will be developed and discussed with respect to the role of geothermal energy use.

Kontakt: Dr. Peter Bayer  

Status: Offen

Professur: Löw

Räumlich hochauflösende Bestimmung von hydraulischen Untergrundparametern mit multi-level Slug-Tests

Die hochauflösende quantitative Bestimmung von hydraulischen Untergrundparametern ist eine Voraussetzung für die Vorhersage von Stofftransport im Grundwasser. Multi-level Slug-Tests zeigen ein grosses Potential bezüglich der räumlich hochauflösenden Bestimmung von hydraulischen Parametern. An einem sehr gut untersuchten Testfeld in Felben-Wellhausen im Thurtal (alluvialer Schotter-Grundwasserleiter) soll eine Reihe von multi-level Slug-Tests durchgeführt werden um die hydraulische Durchlässigkeit in verschiedenen Tiefen über die ganze Mächtigkeit des Grundwasserleiters zu bestimmen. Die Tests sollen mit analytischen Lösungsverfahren (Geradlinienverfahren und Typkurvenverfahren) ausgewertet werden. Abschliessend sollen die Ergebnisse mit Pumpversuchsdaten und bereits vorhandenen Labordaten verglichen und validiert werden. Die Arbeiten werden in enger Zusammenarbeit mit dem Department Wasserressourcen und Trinkwasser/EAWAG durchgeführt.

Kontakt: Dr. Ralf Brauchler  

Status: Offen

Professur: Löw

Bestimmung der Anisotropie der hydraulischen Durchlässigkeit mit cross-well Slug-Tests

Die Auswertung von cross-well Slug-Tests ermöglicht die Bestimmung der hydraulischen Parameter spezifischer Speicherkoeffizient und hydraulische Durchlässigkeit. Darüber hinaus ist es möglich unter Verwendung von Doppelpacker-Systemen Messkonfigurationen zu realisieren, die es ermöglichen die Anisotropie der hydraulischen Durchlässigkeit, d.h. Verhältnis der horizontalen zur vertikalen hydraulischen Durchlässigkeit, zu bestimmen. Das Ziel dieser Arbeit ist es, die Anisotropie der hydraulischen Durchlässigkeit mit analytischen Lösungen zu bestimmen. Dafür sollen 30 cross-well Slug-Tests, die unter Verwendung einer tomographischen Messanordnung bereits durchgeführt wurden, mit dem Typkurvenverfahren ausgewertet werden. Die ermittelten hydraulischen Parameter (vertikale und horizontale hydraulische Durchlässigkeit und spezifischer Speicher) sollen zusammen mit Labor- und Pumpversuchsdaten analysiert werden.

Kontakt: Dr. Ralf Brauchler  

Status: Offen

Professur: Löw

Sediment Transport by Snow Avalanches

Dense wet-snow avalanches breaking through to the base of the snow pack or overriding snow-free surfaces can entrain basal material and thus act as important agents of sediment transport in steep Alpine catchments. This thesis will explore the erosional capabilities of snow avalanches through analysis of their deposits and of the characteristic landforms they create. Special emphasis will be given to quantifying avalanche sediment transport with field measurements. Field work will focus on the region of the Mattertal in Canton Valais.

Kontakt: Dr. Jeffrey Moore  

Status: Offen

Professur: Löw

Erosion of Bedrock Gullies by Snow Avalanches

Snow avalanches can act as primary erosional agents in steep bedrock terrain, yet their influence on shaping these landscapes is rarely appreciated. This thesis will explore the erosional capabilities of snow avalanches through field observations of bedrock surfaces in avalanche-affected gullies and through numerical modeling of avalanche flow dynamics. Field work will focus on the region of the Mattertal in Canton Valais.

Kontakt: Dr. Jeffrey Moore  

Status: Offen

Professur: Löw

Exfoliation joints and quantitative mapping of joint fractographic markings in the Grimsel Pass area (Berner Oberland)

Exfoliation joints are relatively young joints restricted to the shallow subsurface and have orientations characteristically sub-parallel to the overall landscape surface morphology. The occurrence of exfoliation joints can have major influence on slope stability and near-surface excavations. The goal of this thesis is to generate detailed surface models of exfoliation joints and to quantitatively map exfoliation joint surface markings remote and in-situ. You will learn how to create, visualize, and analyse your own 3-D models using photogrammetry and tachymeter measurements. You should bring along high motivation and cautiousness in handling expensive field equipment. Rock climbing experience is a plus but not a must-have! You will be supported in the field.

Kontakt: Martin Ziegler   Prof. Simon Löw  

Status: Offen

Professur: Löw

Mantle convection and lithosphere dynamics in extrasolar Super-Earths

In the last 15 years, hundreds of planets have been found around other stars. A few of these are rocky planets, perhaps similar to Earth but larger. There is intense interest in whether these could harbor life, and an essential ingredient for life is thought to be plate tectonics, which is related to mantle convection. Due to the much higher pressures inside super-Earths, the dynamics might be quite different from in Earth. In this project, numerical simulations of mantle convection and lithosphere dynamics will be performed, in order to understand better key aspects of the dynamics, and make predictions about planets that have been or will be discovered.

Kontakt: Paul Tackley  

Status: Offen

Professur: Tackley

The consistency and interpretation of magnetic observatory records

Geomagnetic observatories are globally distributed and supply valuable data pertaining to the Earth's interior and the state of the external environment (ionosphere, magnetosphere). Our ability to draw conclusions depends critically on the accuracy and consistency of such data, particularly when the signal to be measured is of small amplitude (e.g. that concerned with induced electrical currents in the Earth's mantle). Most observatories have both an absolute scalar magnetometer, and a three-component vector magnetometer; the former is used along with absolute observations of declination and inclination to calibrate the latter. Few observatories make a routine check on the difference in the measured total field signal between the two instruments. Here we propose to look at this diagnostic for as many globally-distributed observatories as possible, and see whether the two are consistent. Any difference in the two signals demands an interpretation, either in terms of a physical phenomenon or a limitation with the instrumentation. This simple check has rarely been carried out and will lead to new insight into observatory operations.

Kontakt: Prof. Andrew Jackson  

Status: Offen

Professur: Jackson

Mixing in Earth's mantle by vigorous, three-dimensional non-Newtonian convection

From geochemical measurements we know that Earth's mantle is chemically very heterogeneous, and most likely this heterogeneity is caused mainly by the introduction of chemically-layered slabs at subduction zones, which then get stirred and mixed by mantle convection. Thus, the details of stirring and mixing in the mantle are of great interest to both geochemists and geophysicists, but have so far been studied mainly by two-dimensional calculations. In this project, three-dimensional numerical convection simulations will be performed to study mixing in three-dimensional convection, focusing particularly on the effect of non-Newtonian viscosity (i.e., strain rate is not necessarily proportional to stress).

Kontakt: Prof. Paul Tackley  

Status: Offen

Professur: Tackley

Early evolution of Vesta

Giant asteroid Vesta is believed to be a leftover building block of the terrestrial planets. The presence of a basaltic crust on Vesta indicates significant melting during the early evolution, resulting in iron-silicate separation. Recent studies of meteorites originating from Vesta suggest the presence of an early internal magnetic field induced by convection in the molten iron core. In this study you will investigate the early evolution of Vesta using 2D numerical simulations including a parametrized dynamo model. The results will be compared with the meteorite measurements and will help to get a better understanding on the early evolution of Vesta and other early formed bodies.

Kontakt: Gregor Golabek  

Status: Offen

Professur: Tackley

3D solid modelling in geodynamics

In mechanical engineering, the processes of using numerical (i.e. finite element) analysis to understand the behaviour of a dynamic system typically follows such a work flow; 1) "Construct geometry" - use a CAD package to develop a 3D solid model of your problem, 2) "Construct mesh" - convert the solid model into a three dimensional tetrahedral (or hexahedral) mesh; 3) "Import" - import generated mesh into numerical analysis software; 4) "Analysis" - perform finite element analysis and post-process results. In computational geodynamics, the development of stages 1,2 is severely lacking. This makes the construction of initial conditions for three-dimensional modelling extremely cumbersome. In this project we will develop a work flow, using open source tools to enable the geometry of complex geological systems to be described, and subsequently imported into our geodynamic numerical models.

Kontakt: Dave May  

Status: Offen

Professur: Tackley

The consistency and interpretation of magnetic observatory records

Geomagnetic observatories are globally distributed and supply valuable data pertaining to the Earth's interior and the state of the external environment (ionosphere, magnetosphere). Our ability to draw conclusions depends critically on the accuracy and consistency of such data, particularly when the signal to be measured is of small amplitude (e.g. that concerned with induced electrical currents in the Earth's mantle). Most observatories have both an absolute scalar magnetometer, and a three-component vector magnetometer; the former is used along with absolute observations of declination and inclination to calibrate the latter. Few observatories make a routine check on the difference in the measured total field signal between the two instruments. Here we propose to look at this diagnostic for as many globally-distributed observatories as possible, and see whether the two are consistent. Any difference in the two signals demands an interpretation, either in terms of a physical phenomenon or a limitation with the instrumentation. This simple check has rarely been carried out and will lead to new insight into observatory operations.

Kontakt: Jackson Andy  

Status: Offen

Professur: Jackson

The consistency and interpretation of magnetic observatory records

Geomagnetic observatories are globally distributed and supply valuable data pertaining to the Earth's interior and the state of the external environment (ionosphere, magnetosphere). Our ability to draw conclusions depends critically on the accuracy and consistency of such data, particularly when the signal to be measured is of small amplitude (e.g. that concerned with induced electrical currents in the Earth's mantle). Most observatories have both an absolute scalar magnetometer, and a three-component vector magnetometer; the former is used along with absolute observations of declination and inclination to calibrate the latter. Few observatories make a routine check on the difference in the measured total field signal between the two instruments. Here we propose to look at this diagnostic for as many globally-distributed observatories as possible, and see whether the two are consistent. Any difference in the two signals demands an interpretation, either in terms of a physical phenomenon or a limitation with the instrumentation. This simple check has rarely been carried out and will lead to new insight into observatory operations.

Kontakt: Andrew Jackson  

Status: Offen

Professur: Jackson

The magnetic observations of the Darwin's ship Beagle, and the global magnetic field in the 19th century

Numerous observations of the magnetic field were made by Captain FitzRoy on the Beagle and Adventure, and these can be used to constrain the change in the magnetic field from the 19th century until the present day. Together with other contemporary measurements, we will use these observations to constrain the magnetic field in the 19th century. FitzRoy's observations are unusual in being 3 component measurements, since the method for determining absolute intensity had only recently been determined by Gauss in 1832. We plan to revisit these original intensities in the light of this discovery. Our ultimoate aim is to make a mathematical model of the magnetic field and thus learn about the state of the Earth's core at that time.

Kontakt: Andrew Jackson  

Status: Offen

Professur: Jackson

Analysis of Induced and Remanent Crustal Magnetism of France

Crustal magnetisation is generally attributed to two types of source: induced magnetisation and remanent magnetisation. The former varies with the inducing field, the latter is static. We aim to try to resolve the different cntributions in France using modern and historical datasets. The oldest data originate in a survey performed in 1888, and modern data are from aeromagnetic surveys. We will examine the question of whether appreciable change in the crustal field can be detected with time.

Kontakt: Andrew Jackson  

Status: Offen

Professur: Jackson

Investigating the magnetic anisotropy of dolomites from Naxos, Greece

The anisotropy of magnetic susceptibility (AMS) in a set of dolomites is investigated in an attempt to relate their magnetic fabric with the metamorphic grade and structural geology of marbles from Naxos, Greece. Low- and high-field magnetic susceptibility is measured at room and liquid nitrogen temperature using instrumentation at the Laboratory for Natural Magnetism (LNM), ETH Zurich.

Kontakt: Ann Hirt  

Status: Offen

Professur: Jackson

Rock magnetic properties of a Roman age lime kiln at Oensingen

A Roman age kiln was sampled at Oensingen to reconstruct the geomagnetic field during that time. This project concentrates on determining the magnetic minerals present in the samples, their sizes, and how the magnetic signal changes with time. Standard rock magnetic techniques will be used for the characterization, and will be performed selected specimens. This information is valuable to assess the stability of the magnetic signal, and to tell how reliable is the directional data that will be measured.

Kontakt: Fabio Donadini  

Status: Offen

Professur: Jackson

Experimental Characterisation of the Core-Mantle or subsurface ocean-Ice shell viscous coupling in presence of boundary layer turbulence.

The viscous coupling between a liquid core of a planet and the surrounding solid mantle (or a subsurface ocean and the surrounding ice shell) remains a challenging question that has fundamental implications in planetary dynamics. The classical approach consist in introducing a effective (turbulent) viscosity in the laminar models to account for the boundary layer turbulence. The prior experimental investigations have yielded contradictory results. Thus, the validity of this approach remains questionable. In the present project, we propose to test the concept of the effective (turbulent) viscosity in a more simple yet very general case. The experiments consist of a rapidly rotating water filled cylinder with a rough bottom surface (like sand paper) that is abruptly accelerated or decelerated. Measurements of the time needed for the fluid to reach the new state of solid body rotation will allow us to test if the effect of the turbulence generated by the roughness can be parametrized by an effective viscosity in a laminar model or not.

Kontakt: Jérôme Noir  

Status: Offen

Professur: Jackson

Investigation of magnetic traits of sand dunes in SW Africa.

The mineral-magnetic compositions of sand samples collected along the Pacific coast of Namibia and Angola will be investigated by hysteresis and susceptibility measurements between room temperature and 700°C. The thermal variation of the magnetic pattern of the samples provides information about the magnetic carriers and their source areas. Knowing the source areas is a key to deduce eolian transport mechanism during desertification. In combination with published climate information these data will be used to reconstruct the development of the Namibian Sand Sea since early Miocene. This project addresses students with interests in geophysical experiments in the context of the broad field of landscape development.

Kontakt: Andreas Gehring  

Status: Offen

Professur: Jackson

Rock magnetic properties of a Roman age lime kiln at Oensingen

A Roman age kiln was sampled at Oensingen to reconstruct the geomagnetic field during that time. This project concentrates on determining the magnetic minerals present in the samples, their sizes, and how the magnetic signal changes with time. Standard rock magnetic techniques will be used for the characterization, and will be performed selected specimens. This information is valuable to assess the stability of the magnetic signal, and to tell how reliable is the directional data that will be measured.

Kontakt: Fabio Donadini  

Status: Offen

Professur: Jackson

Performance of the Swiss Seismological Network

The Swiss Strong Motion Network (SSMNet), as well as the Swiss Digital Network (SDSNet) are in a period of fast growth. One of the objective of the SSMNet is to provide good recordings for source, propagation and site effects studies, as well as for engineering purposes. The objective of the proposed work is to propose and display parameters showing the performance of the network in providing good quality recordings. Good quality recordings are defined by a sufficient signal-to-noise ratio in a determined frequency band. Various magnitude earthquakes will be simulated and compared to the noise at the seismic stations of the network. Maps of Switzerland displaying the results will be produced. Strengths and limitations of the network will be deduced.

Kontakt: Clotaire Michel   Benjamin Edwards   Donat Fäh  

Status: Offen

Professur: SED

3-D analysis of satellite EM responses

Recent global electromagnetic (EM) induction studies using the geomagnetic field measured by modern satellite missions Oersted, CHAMP and SAC-C reveal hemispherical asymmetry in the recovered EM responses. This project aims to answer the question whether the asymmetry can be explained by the difference between mantle electrical conductivities beneath oceans and continents. The student will run 3-D global EM induction simulations, process their outputs, and analyze the predicted and observed responses.

Kontakt: Alexey Kuvshinov  

Status: Offen

Professur: Jackson

Paleosecular Variation Record from a Swiss lake

This project involves measuring relative paleointensity and paleosecular variation from cores from a Swiss lake, Soppensee. The data will be used to help construct a master curve for Switzerland that can be used in models of the Earth's field behavior during the past two thousand years

Kontakt: Ann Hirg  

Status: Offen

Professur: Jackson

New time series analysis of global induction data

The most challenging problem of modern global electromagnetic (EM) induction studies is the recovery of three-dimensional (3-D) variations of electrical conductivity in the Earth's mantle. A necessary prerequisite to tackle this problem is the preparation of good quality EM responses to invert them in a 3-D framework. In this project the student will test different signal processing approaches to obtain new responses for a worldwide network of geomagnetic observatories.

Kontakt: Alexei Kuvshinov  

Status: Offen

Professur: Jackson

Schwermetall Vorkommen im Verrucano (Kt. GL & GR)

Im Abstrom von Vererzungen werden aus Bächen Mineral-Konzentrate entnommen und mittels Röntgenfluoreszenz (XRF) auf ihren Metallgehalt sowie mittels Alpha- und Gammaspektrometrie auf den Gehalt an Uran und Thorium analysiert. Weiter werden in Wasserproben die Nuklide der Uran-Thorium-Serie bestimmt. Ziel: Aussagen zur geogenen Belastung der Umwelt durch Schwermetall-Anreicherungen. Bedingung: Wasserfest und berggängig

Kontakt: Franz Schenker   Heinz Surbeck  

Status: Besetzt

Professur: Löw

Schwermetall Vorkommen im Verrucano (Kt. GL & GR)

Im Abstrom von Vererzungen werden aus Bächen Mineral-Konzentrate entnommen und mittels Röntgenfluoreszenz (XRF) auf ihren Metallgehalt sowie mittels Alpha- und Gammaspektrometrie auf den Gehalt an Uran und Thorium analysiert. Weiter werden in Wasserproben die Nuklide der Uran-Thorium-Serie bestimmt. Ziel: Aussagen zur geogenen Belastung der Umwelt durch Schwermetall-Anreicherungen. Bedingung: Wasserfest und berggängig

Kontakt: Franz Schenker   Heinz Surbeck  

Status: Besetzt

Professur: Extern

Localisation and ore type of a new gold prospect in the Altar region, Argentina

Determine the genetic type of a newly discovered gold occurrence associated with the Altar porphyry copper deposit, using petrographic study of vein, altered intrusive rocks and fluid inclusions.

Kontakt: Christoph Heinrich   MSc students of Altar project   R. Rey (Stillwater)  

Status: Besetzt

Professur: Heinrich