The research group Geothermics & Radiometrics (GTR) has been established in 1978 by Prof. L. Rybach at the Institute of Geophysics at ETH Zürich (ORGANIGRAM). The group is operating under the administrative responsibility of Prof. Dr. W. Lowrie, Institute of Geophysics. Since 1978, the research in the GTR group has been continuously developed and structured and can now be subdivided into three sections anchored in environmental and general Earth sciences:
General geothermics
Research focuses on aspects of global geosciences
but also to deep tunnelling, using computational and laboratory methods.
Applied geothermics
Research directs on international and national
cooperative projects such as high enthalpy systems like Hot Dry Rock (HDR)
or low enthalpy systems like borehole heat exchanger and aquifer systems.
Radiometrics
Research based on airborne data acquisition,
processing and interpretation but also on laboratory measurements.
Various group members have developed strong
national and international ties and are presiding in several committees.
General geothermics
In this division research topics related to
global and local Earth Sciences are investigated. Thus, in the past heat
flow analysis of Switzerland, West Anatolia (Polyproject Marmara) and of
the German Continental Deep Drilling project were treated by analytical
and numerical methods. Especially the 3-D investigations of subsurface
temperature fields performed with our finite element development FRACTure
attracted high interest from many foreign research institutions who now
have permission to work with this program (University of Utah, MIT Boston,
Geological Survey of Finland, GEOMAR Kiel, Industrial Research Wellington,
Czech Academy of Science, ...). Another topic recently treated are inversions
of ground surface temperature which allow to assess former climatic conditions
within the last ~500 years.
There exists many links to related scientific
fields which have been continuously developed. In the framework of investigating
conditions of the Swiss deep tunnelling NEAT project temperature prognoses
have been performed for the planned Gotthard tunnel (NEAT).
At mid term, our collaboration is foreseen in a major national scientific
project lead by the ETH group of Engineering Geology. New analyses show,
that the 3-D subsurface temperature field at the Gotthard is the key for
understanding Apatite Fission-Track ages measured in the past by various
authors. Our analysis permits to develop a consistent uplift and erosion
model of the Central Swiss Alps during the last 107 years. A strong impulse
from these recent findings combined with follow-up research is expected
for the future. These numerical results strongly rely on laboratory measurements
(LAB-Measurement)
These investigations not only prepare the
ground for actual geothermal topics but also provide the essential information
on crustal temperature distribution and the heat flow from greater depths
which constrains the necessary boundary conditions in geodynamic models.
Applied geothermics
In this division research is backed mostly
by national and international institutions. It represents the only institution
in Switzerland which covers broadly the various aspects of applied geothermics.
Several former PhD student from this division are driving today successfully
their own consultancy companies. Especially, this division is well integrated
in the national CO2 free programmes directed by the BfE and in the international
HDR research supported by the BBW and European funding agencies.
Currently, several PhD and diploma students
have been educated on various aspects of borehole heat exchangers (shallow
geoth. Resources). The research developing from these studies became
internationally acknowledged and will be continued in a PSEL (Projekt-
und Studienfonds der Elektrizitätswirtschaft) project. Driven by the
interest of major Swiss electricity companies to penetrate the heat market
it is foreseen that the new PhD student will investigate and optimise borehole
heat exchanger systems.
HDR research is performed in this group since
1986 attaining now a high degree of internationally acknowledged expertise.
Especially, for geosciences the new data collected from worldwide HDR sites
represent a unique treasure of information from crystalline deep basement
which allows to constrain in-situ hydraulic, thermal and stress conditions.
Our actual studies are focused on the European HDR site in Soultz (France)
(Soultz) and
are performed in cooperation with partners in the framework of EU projects.
Such project represents an ideal basis for our students to acquire international
field practice experience.
The progress of the Swiss Deep Heat Mining
project (Deep
Heat Mining) could demand the need for new studies at mid term.
This division fulfils four different tasks:
Airborne environmental monitoring, emergency preparedness, measurements
for geothermics, geological mapping.
The first two tasks represent Swiss national
duties and are actually closely interacting: the airborne environmental
survey is used for the observation of Swiss nuclear power plants and nuclear
accelerators and provides a background image of the actual radiometric
situation which provides clues for preservation of evidence. In case of
Satellite crashes, lost nuclear sources or other nuclear accidents, the
system developed by this group is used by the Swiss Nationale Alarmzentrale
NAZ for emergency investigations. The hard- and software developed by this
group are highly reputed in the Swiss neighbouring countries. Collaborating
foreign institutions are the French "Commission d'Energie Atomique", the
Austrian "Geologische Bundesanstalt", the German "Bundesamt für Strahlenschutz"
and the Swedish Radiation Protection Institute. The current ground activities
are funded by the HSK, the airborne activities by the NAZ.
The airborne gamma-ray survey (airborne
gamma-ray) has been recently combined with geological mapping. Excellent
agreement with lithological units have been found especially in the Eastern
Swiss Alps and the Black Forest. The airborne measurements are calibrated
by laboratory facilities. Here, the heat production of rock samples can
be also determined.
This division of GTR represents a unique
situation at ETH since it comprises one of the few gamma-spectrometers
at ETH and operates the only one used in teaching (Praktikum) at ETH (LAB-Measurement).
This situation offers the potential for using synergies by cooperation
with the Department of Environmental Sciences, ETHZ, for various aspects
of environmental sciences and education (examination of water quality and
terrestrial samples). Previously substantial radon work is now dormant;
field and laboratory instrumentation is still available.