printlogo
https://www.ethz.ch/
Herzlich Willkommen
 
print
  

Topics of Master Theses at the Schweizerischer Erdbebendienst (SED)

For Lectures


Edit Topics of MSc Thesis.

Course Catalogue

The course catalogue of ETH Zurich lists all the courses held at ETH.

MyStudies

MyStudies is the portal to various services and administration issues for students.

 

Geothermal Energy: Towards a Meaningful Probabilistic Seismic Hazard and Risk Assessment of Induced Seismicity

Geothermal Energy is a promising source of alternative energy; however, lingering questions about the seismic hazard associated with the injection of water under high-pressure at seismogenic depths need to be resolved (e.g., Giardini 2009). There is a growing realization that the exploitation of geothermal energy cannot be done with zero risk, yet so far there is no consensus in the scientific community on how to best assess and mitigate the seismic hazard and risk of induced seismicity.  This project will contribute to an ongoing effort at the Swiss Seismological Service to define ways how to compute probabilistically the seismic hazard and risk of induced seismicity during the various phases of a geothermal project, and how to assess in a comprehensive way the uncertainty of the estimate, using, for example, logic trees.  This work will be based on the analysis of a number of physics-based and statistical models of induced sequences against a wide range of data. In addition, we will compare the final hazard and risk to the ones from other natural and man-made risk, and consider effective communication strategies with the public, the media and decision makers.

Kontakt: Stefan Wiemer  

Status: Offen

Professur: SED

Quantifying ground motion variability near the source from ground motion database estimated from earthquake rupture models.

Current empirical ground motion prediction equations (GMPE) are insufficient for the prediction of near?source ground motion for use in seismic hazard and risk assessment and earthquake?resistant structural design. That is because these GMPE are based solely on recorded data which are sparse in the near field, and which do not adequately represent the source effects and the geologic amplification mechanisms that have been identified in numerical simulations.Then ground motion based on physics?based numerical models are required if we are to adequately assess the level and variability of near?source ground motion, for events consistent with the maximum expected earthquake in the zone. In the present project we will evaluate ground motion simulated from hundreds of rupture dynamic models that we have currently stored in our database. The analysis consist in the estimation of the statistical distribution of strong ground motion parameters, such as peak ground velocity (PGV), peak ground acceleration (PGA), spectral ordinates, etc, for a given distance and event magnitude. With the goal to derive ground motion scaling relations near the source incorporating effect of the source such as rupture directivity due to subshear and supershear rupture speed, and compare them with empirical GMPE

Kontakt: Luis A. Dalguer  

Status: Offen

Professur: SED

Investigating the possibility of fault opening during earthquake rupture dynamic

Earthquake fault rupture is usually idealized as a purely dynamically running shear crack on a frictional interface embedded in the earth. While this idealization has proven to be a useful foundation for analyzing natural earthquakes, it is also recognized that earthquake faulting may also have transient tensile components. Possible cause of fault opening is the reduction of the normal stress acting on the fault. Such us normal stress perturbation may be produced during dynamic rupture by collisions of geometrical asperities, kink faults, bimaterial interfaces, interaction of dipping fault with the free?surface, and also due to other external mechanism triggered by fluid flux and pore fluid pressure changes as a consequence of for example of geothermal, volcanic and other extensional regimes. Additionally, due to the nature of the gravitational loading, the absolute value of normal stress is depth-dependent. This results in lower values of normal stress in the shallow zone. Therefore, surface?rupturing earthquakes are naturally prone to be exposed to fault opening mechanism described above. In the present project we will explore the mechanisms described above using simple finite difference code already set to study fault opening.

Kontakt: Luis A. Dalguer  

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: Jan Burjanek   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: Michel Clotaire   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: Jan Burjanek   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: Valerio Poggi   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: Ben Edwards   Valerio Poggi   Donat Fäh  

Status: Offen

Professur: SED

Short-term seismicity forecasts from physics-based models:  Quantifying the effect of small earthquakes

Short-term earthquake forecasting is one of the most demanding challenges seismologists face. Although a wealth of information from seismic and geodetic networks together with long-term knowledge about seismicity and fault-network behaviour exists, statistical and in particular physics-based forecast models are still far from being able to predict the next 24h at a high level of credibility. As a continuation of a ETH masterthesis (M. A. Meier, “The importance of small aftershocks for earthquake triggering”), this masterthesis will generate seismicity forecasts of a combined Coulomb stress change / a rate & state friction model. The modelling will take advantage of including small aftershocks. In a comparative analysis with other forecast models, the probability gain in forecasting upcoming events will be quantified with rigorous statistical tests. As a first test case, the method will be applied to the 1992 Mw 7.2 Landers earthquake in southern California but shall be extended to recent similar sized earthquakes for which high precision data is available. The thesis mainly addresses the question whether smaall earthquakes help to better explain “future” earthquakes.

Kontakt: Jochen Wössner   Luis A. Dalguer  

Status: Offen

Professur: SED

Recurrence characteristics of European Active Faults – What recurrence statistics do they obey?

Seismic hazard assessment heavily relies on the definition of earthquake sources and often only flat areal source zonation models based on rough and subjective seismo-tectonic considerations have been taken to generate these models. Currently, small and large scale projects such as the EU-FP7 project Seismic Hazard Harmonization in Europe (SHARE, www.share-eu.org) and the Global Earthquake Initiative (GEM, www.globalearthquakemodel.org) generated strong efforts to increase the knowledge on active faulting around the world and in particular for the Euro-Mediterranean region (www. http://diss.rm.ingv.it/diss/). In addition, harmonized earthquake catalogs are created that enable to characterize the activity of the faults. This master thesis will address the question of recurrence of small and large earthquakes on active fault segments and entire seismogenic sources, an essential characterization for any seismic hazard analysis.

Kontakt: Jochen Wössner   Stefan Wiemer  

Status: Offen

Professur: SED

Comparison of large-earthquakes and finite-fault simulations with point source models

Simple point source earthquake models have routinely been shown to perform well in modelling the far-field ground-motion from small to moderate (<Mw=5.5) earthquakes. Recent work has also shown that such models can be used to model even larger earthquakes (Mw=7) by adapting the model for relatively simple geometric effects. The point-source model is therefore a very useful tool for simulating expected ground-motions in regions of low or moderate seismicity, where empirical observations of stronger earthquakes are usually not available, or limited to historical documentation. This project will focus on quantifying the usefulness and limitations of the adapted point-source models by comparing modelled ground-motion with recordings of large earthquakes. We will also investigate the model in terms of the understanding of parameterisation, such as the stress drop, by comparing point source models with existing numerical earthquake simulations.

Kontakt: Ben Edwards   Donat Fäh  

Status: Offen

Professur: SED

Source identification by back-projections of SDSNET noise and weak motion records

This thesis will focus on application of back-projection methodologies to data recorded on the Swiss permanent broadband network. The scope is to investigate the feasibility of these methods to characterise the source of future large earthquakes in Switzerland and/or to identify tremor beneath the Swiss Alps. In a first step back-projections will be applied to weak motion records of M < 4 earthquakes acquired during the last decades to validate the method in the light of the available velocity models, station coverage and signal to noise ratio. Further verifications with synthetic data for point and finite sources will follow to calibrate the method and to test the limits of back-projecting SDSnet records of future M 6 events. The method may also be applied for the detection of low-frequency tremor in the Alpine area.

Kontakt: Daniel Roten   donat Fäh  

Status: Offen

Professur: SED

Developing a statistical framework for earthquake rupture process for physics-based ground motion simulation

We develop a statistical framework that controls physical earthquake rupture processes, which is also consistent with the statistical framework used in ground motion characterization. We adopt the concept of 1-point and 2-point statistics in the context of a spatial random field model, which is commonly used in the geostatistics community. We will perform a series of full dynamic rupture modeling with high performance computing (HPC) and investigate how earthquake source affects ground motion characteristics. In this thesis one can formulate the spatial heterogeneity of dynamic source parameters such as stress drop and fracture energy in the framework of 1-point and 2-point statistics and perform full dynamic rupture modeling that produces physically self-consistent kinematic source motions on the fault and ground motions on the surface. He or she will also analyze produced kinematic source motions and ground motions in the same framework of 1-point and 2-point statistics. This study will greatly help to build up a statistical framework that controls finite earthquake rupture process in the context of pseudo-dynamic source modeling for physics-based ground motion simulation.

Kontakt: Seok Goo Song   Luis Angel Dalguer  

Status: Offen

Professur: SED

Prediction of Damage related to Enhanced Geothermal Systems - the case of Basel

Geothermal Systems offer the potential for a clean, renewable energy and heating source by tapping into natural heat-reservoirs kilometres beneath the earth surface but cause fracturing, and consequently micro-seismicity. Many Enhanced Geothermal Systems (EGS) projects have recently been launched all over the world, but the failure of the Basel EGS in 2006, with estimated losses of over $9M (Giardini, 2009), showed how important prior risk analysis was. Predicting damage that could be caused by moderate earthquakes induced by an EGS is therefore critical to plan new projects of energy production using this renewable energy source. Unfortunately, existing procedures of earthquake risk assessment are not well adapted to this kind of analysis, where minor building damage (cracks, falling roof-tiles, chimney collapse) is expected rather than building collapse and casualties. In this Master's project, we propose to develop and test a new risk assessment method based on ground-motion and structural-response physics, rather than on empirical damage relationships, as was done up to now. Risk scenarios using existing ground-motion prediction equations (GMPEs) and fragility curves will be performed on the city of Basel and the damage results will be compared to that observed in 2006. Moreover, developments in the GMPEs, to take into account the radiation pattern, and the fragility curves, to account for non-structural elements, may be undertaken. Different building inventories of Basel will be used investigating also the related uncertainties. New field data in buildings may be collected in order to improve the fragility data.

Kontakt: Benjamin Edwards   Clotaire Michel   Donat Fäh  

Status: Offen

Professur: SED

 

Wichtiger Hinweis:
Diese Website wird in älteren Versionen von Netscape ohne graphische Elemente dargestellt. Die Funktionalität der Website ist aber trotzdem gewährleistet. Wenn Sie diese Website regelmässig benutzen, empfehlen wir Ihnen, auf Ihrem Computer einen aktuellen Browser zu installieren. Weitere Informationen finden Sie auf
folgender Seite.

Important Note:
The content in this site is accessible to any browser or Internet device, however, some graphics will display correctly only in the newer versions of Netscape. To get the most out of our site we suggest you upgrade to a newer browser.
More information

© 2014 ETH Zürich | Impressum | Disclaimer | 26.3.2013
top