Topics Master in Earth Sciences ETH

Landslides are one of the most dangerous natural hazards, killing thousands of people globally each year. Often, landslides are detected only after they’ve failed catastrophically, but there can be warning signs prior to failure, such as an exponential increase in landslide speed. In light of anthropogenic climate change, there is particular interest in landslides which develop near retreating glaciers as they are “debuttressed,” or lose lateral support, from the glaciers. A global dataset of annual glacier velocities from 1984-2022 is available (https://its-live.jpl.nasa.gov/) which also covers non-glaciated terrain within several kilometers of glaciers, allowing for analysis of paraglacial landslides. This MSc thesis will focus on the detection and characterization of these features using GIS software and satellite imagery. The initial study area will be Alaska, but may be expanded to other regions given sufficient time. The goal is to create a database of paraglacial landslides and then analyze the behavior of the landslides throughout time. A background in geospatial analysis would be helpful but is not mandatory for this work. The student should be willing to learn new concepts in glaciology, geology, and geomorphology.

- Identification of landslides from a global velocity dataset and satellite imagery - Creation of a database to catalog the landslides (location, area, average velocity) - Analysis of the landslide velocity over time - Comparison to an existing landslide dataset in Alaska

For further information, please contact Ms. Jane Walden (walden@vaw.baug.ethz.ch) or Dr. Mylène Jacquemart (jacquemart@vaw.baug.ethz.ch).

Antarctic ice streams feed approximately 90% of Antarctica’s ice into the world’s oceans. These ice streams flow to the ocean through a combination of internal deformation and by sliding over and deforming the rock and sediment that underlies them. Processes at the base of the ice are particularly important to understand as they can result in rapid changes in ice flow velocity at time scales of hours to days and years to centuries. Many of these processes emit acoustic signals which can be recorded at the ice surface making passive-source seismology an ideal tool with which to study them. This project will use existing data to examine the transition where the grounded Kamb Ice Stream crosses into the Ross Ice Shelf and contributes to global sea level.

Project aims include identifying, locating, and characterising seismicity from sources at the base of the ice stream and within the ice shelf. These sources include water flow in a large subglacial drainage channel, and crevasse formation due to flexure of the floating ice shelf as it rises and falls with the tide. To achieve the aims you will use existing tools (e.g. obspy) to process and analyse the data. Basic programming skills, or the desire to develop them, are required. The ideal candidate would also have an interest in glaciology and applied geophysics. Should time allow, the results will be compared with other complementary data (e.g. Global Navigation Satellite System positioning) and model output (e.g. subglacial water routing.)

For further information please contact Dr. Huw Horgan (horganh@ethz.ch)

Retreating glaciers are icons of climate change, impact regional runoff and drivers of global sea-level rise. Numerous dynamic feedbacks amplify glacier sensitivity to atmospheric forcing, such as ice surface darkening or elevation lowering. This project aims at investigating the cryo-hydraulic amplification process by which energy fluxes carried by meltwater flowing englacially contribute to melting glaciers from the inside, thus accelerating their collapse. The study area is Gornergletscher, the second largest glacier in Europe. Gornergletscher is located in Valais, Switzerland, and recently detached from its main tongue, the Grenzgletscher. The detachment from the tributary glaciers does not only suppress the alimentation of ice from the upper accumulation zone but also provides the conditions for lateral meltwater streams to enter the main glacier body. By releasing their latent heat directly into the englacial interior, vast ice contact caves have been carved out.

The project will investigate the retreat and collapse of the Gorner-Grenz junction in the last ten years and will quantify the role of the above cryo-hydraulic process in the overall ice-loss budget. This will be done by combining (i) time series of aerial images and digital terrain models, with (ii) a dataset of meltwater temperature and discharge, as well as (iii) 3D imaging of ice contact caves, collected during two summer field expeditions (2022-2023). The project will provide insights into a process that enhances the demise of Alpine glaciers, and will foster process-understanding relevant to larger ice masses.

For further information please contact Dr. Francesco Sauro (cescosauro@milesbeyond.it) or Prof. Daniel Farinotti (daniel.farinotti@ethz.ch).

The surface mass balance of a glacier is critical in the long-term evolution of a glacier, as it reflects the difference between the total sum of the accumulation (mass gain) and the ablation (mass loss). It is typically expressed in metres of water equivalent per year. When the surface mass balance is positive, the glacier has gained mass over the year, while a negative balance indicates a nett mass loss. One of the crucial elements in mass balance modelling is the albedo, being the reflectance of the surface. The albedo of the surface of a glacier can change over time because of natural and anthropogenic factors. The aim of this MSc is to analyse whether the Kumtor gold mine in Kyrgyzstan, Central Asia, might influence the mass balance of the surrounding glaciers. The hypothesis is that the mine, which extended last years in the direction of the glacier, produces dust which lowers the reflectance of the glacier surface and increases the melting rate. Taking this into account might be crucial in mass balance modelling.

In this MSc thesis you will apply a mass balance model for two glaciers in Kyrgyzstan (Central Asia), Bordu and Sary-Tor, between 2013 and 2024. You will make use of an (existing) mass balance model, drone data, satellite data (albedo) and temperature and precipitation measurements in the vicinity of the glaciers. The main goal is to analyse the (potential) role of the nearby Kumtor gold mine on the glacier’s mass balance. The preliminary steps of the thesis are: - Getting familiar with the surface mass balance model - Collecting all data (satellite, drone, meteorological) - Model runs and evaluation - Sensitivity analysis and role of dust - Prognostic simulations taking into account the influence of the gold mine

For further information please contact Dr. Lander van Tricht (vantricht@vaw.baug.ethz.ch) or Prof. Dr. Daniel Farinotti (daniel.farinotti@ethz.ch)

The study of exoplanets and their atmospheres has been revolutionised by the advent of the James Webb Space Telescope (JWST), and will continue to grow as other, ground-based telescopes (e.g., the ELT) come online in the coming years. These technological advances have enabled us to spectroscopically characterise the atmospheres of not only giant planets, but a new class of planet, sub-Neptunes (roughly 2 – 3 Earth radii), to unprecedented precision. Common gaseous species such as CH4 and CO2 have recently been detected in the atmosphere of one such sub-Neptune, K2-18b with JWST, together with the tentative detection of other more exotic gases, such as dimethylsulfide (DMS), a potential biomarker (Madhusudhan et al. 2023). However, these spectra are degenerate with respect to composition, and combinations of other molecules at equilibrium (Shorttle et al. 2024) or produced by photochemical reactions (Wogan et al. 2024) may also explain the variation in the observed atmospheric spectrum. Our ability to discern between these possibilities, and thus determine whether such atmospheres are germane to hosting life, is limited by our lack of understanding of how gases mix at high pressures and temperatures. Owing to the masses and radii of typical sub-Neptunes, pressures at the atmosphere-interior interface are thought to be of the order of several gigapascal (GPa; Kite et al. 2020; Vazan et al. 2022). At these conditions, gases in the atmosphere do not mix ideally (that is, their physical properties are not linear functions of their concentrations). As such, the relative abundances of gas species in the atmospheres of sub-Neptunes may differ considerably from that expected for ideal mixtures, thereby leading to substantial uncertainties in the interpretation of atmospheric spectra of these planets. References Kite, E. S., Fegley Jr, B., Schaefer, L., & Ford, E. B. (2020). Atmosphere origins for exoplanet sub-neptunes. The Astrophysical Journal, 891(2), 111. Madhusudhan, N., Sarkar, S., Constantinou, S., Holmberg, M., Piette, A. A., & Moses, J. I. (2023). Carbon-bearing molecules in a possible hycean atmosphere. The Astrophysical Journal Letters, 956(1), L13. Shorttle, O., Jordan, S., Nicholls, H., Lichtenberg, T., & Bower, D. J. (2024). Distinguishing oceans of water from magma on mini-Neptune K2-18b. The Astrophysical Journal Letters, 962(1), L8. Vazan, A., Sari, R. E., & Kessel, R. (2022). A new perspective on the interiors of ice-rich planets: ice–rock mixture instead of ice on top of rock. The Astrophysical Journal, 926(2), 150. Wogan, N. F., Batalha, N. E., Zahnle, K. J., Krissansen-Totton, J., Tsai, S. M., & Hu, R. (2024). JWST observations of K2-18b can be explained by a gas-rich mini-Neptune with no habitable surface. The Astrophysical Journal Letters, 963(1), L7.

The aim of this project is to i) tabulate existing expressions (equations of state; EoS) for non-ideal mixtures among the major atmosphere-forming gases (e.g., in the C-O-H system), ii) quantify/explain differences between these EoS and compare them with experimental data and iii) use optimised expressions for the EoS to better interpret existing JWST spectral data for atmospheres of sub-Neptunes. The candidate should therefore have an interest in at least one of the following topics; thermodynamics, planetary science; astrophysics.

Prof. Paolo Sossi (psossi@ethz.ch) Dr. Dan Bower (dbower@ethz.ch)

As glaciers retreat, they expose oversteepened valley walls which have been weakened by cycles of glaciation. In some cases, large landslides can form in formerly glaciated valleys and may pose a risk to nearby communities and infrastructure. During summer 2023, a 6-sensor seismic network, and station pairs for temporary site-to-reference measurements, were deployed on the lateral slopes of Portage Glacier, Alaska, USA, the site of an active paraglacial landslide. This thesis will involve the analysis of continuous and event-based seismic signals with detection algorithms, noise interferometry, location techniques, and other state-of-the-art processing approaches. The seismological findings will be embedded in a glaciological context to improve our understanding of lateral slope stability in valleys occupied by retreating glaciers. A background in time series analysis, as well as a willingness to learn new concepts in seismology, glaciology, geotechnical engineering, and geomorphology, would be helpful but is not mandatory for this work.

The goal of this thesis is to investigate slope stability, creep, failure events, and subsurface processes. The work will be based on field data collected in 2023 at Portage Glacier. Analysis of the datasets using a variety of methods will determine which portions of the slope are moving, the mechanism of movement, and if the movement is compartmentalized. In particular, the creation of a “hot spots” map is envisioned, where the spatial distribution of events on the slope of interest can be analyzed.

For further information, please contact Dr. Fabian Walter (fabian.walter@wsl.ch) or Ms. Jane Walden (walden@vaw.baug.ethz.ch). Please note that this thesis will be carried out at WSL Birmensdorf.

Accurate modelling of glacier mass balance requires the representation of wind-driven snow processes. Yet, the physical representation of these processes is computationally too expensive to include in standard mass balance models and, therefore, requires simplification via parameterization schemes.

This thesis will compare existing but not widely used parameterizations for different climatic regions (continental Alpine glaciers, maritime glaciers in New Zealand, and seasonal snow cover). The aim is to consolidate existing parameterizations for applications in standard energy and mass balance models.

For further information please contact Dr. Ruzica Dadic

Glaciers supply freshwater to downstream regions where it sustains ecosystems and is used for drinking water, irrigation and energy production. During extreme dry periods late in summer, glacier meltwater can be the primary source of water, especially in mountain regions. You will be analyzing streamflow observations from gauges downstream of the glaciers during such dry periods to investigate the daily meltwater dynamics of glaciers and estimate its volume. You will analyze the variability of these meltwater volumes in space and in time. A particular focus will be on comparing the estimates with glacier model derived estimates of daily meltwater volumes. In a second step, you will investigate how much of the streamflow is sourced from glaciers and how much water comes from other catchment storages during extensive dry periods. Timeseries of streamflow, meteorological data and glacier data are available. Your task will be to design and conduct the analyses and evaluate the results.

1. Detecting dry and warm periods in the timeseries that are suitable to extract a glacier melt signal from streamflow observations 2. Analyzing streamflow dynamics during dry periods and designing a method to infer daily glacier melt dynamics and estimate daily glacier melt volumes 3. Comparing the daily streamflow dynamics with model derived daily glacier melt estimates

For further information please contact Dr. Marit van Tiel (vantiel@vaw.baug.ethz.ch)