GEORG Geothermal Workshop 2016 Plenary Session: On the border between geothermal and volcanology

1. On the border between
geothermal and volcanology
PHILIPPE JOUSSET

2. Geothermal Power Plant
Electricity and heating
Volcano erupting
Science, hazard and risk
(Merapi 2010, discovery.com)
Players
Inspired by Olafur Flovenz (Isor)

3. Geothermal Power Plant
Electricity and heating
Volcano erupting
Science, hazard and risk
(Merapi 2010, discovery.com)
What
characterizes
each?
Inspired by Olafur Flovenz (Isor)

4. Geothermal Power Plant
Electricity and heating
Inspired by Olafur Flovenz (Isor)
Profit driven (Business)
Need
• to secure, expand and manage production
• public acceptance
• reliable information (provided by scientists)
• quick info and results when they decide
Poor knowledge about research methods,
advantage/limitations and time-span required
Volcano erupting
Scientists, hazard and risk
No profit but need money (public and more).
Driven by scientific interest and public safety
Judged by scientific publications and reports.
Main interest: beauty of Science
Do not understand the rush for results
among the industries.
Problems with explaining science and
research methods to industry and public.

8. Vertical
component
5 s5 s

9. Vertical
component
Wayang Windu
geothermal field, West Java,
Indonesia
Merapi volcano
Earthquake prior to
large eruption (2010)
5 s5 s
<=>

10. Jolly et al., 2012,
JVGR 215-216 (2012) 26–39

11. Main scientific objectives
Structure and dynamics of volcanoes, hydrothermal and
geothermal systems from integrated information
Structure
To find where the productive fractures are located (depth, fluid
temperature and composition, …),
– Seismic wave analysis: velocity models, anisotropy, …
– Resistivity distribution: temperature, mineral content, …
– Integrated methods: require rock petrology, fluid content, …
Dynamics
To draw and interpret links between
– Exploitation of the geothermal system/volcanic activity
– Changes in continuously monitored geophysical parameters

12. Main practical questions for the
geothermal industry
• Where are the (very) hot fluids?
• How do they move?
• How should industry exploit them for being sustainable?
Signatures on geophysical data (e.g., seismic velocities/ratio)
Probe the reservoir and its suroundings

13. • Earthquake activity related methods
1. Travel time tomography
• Vp model inversion: rock type
• Vs/Vs ratio: fluid content and type
• Seismic ambient noise cross-correlation methods
2. Ambient noise tomography
3. Reflectivity tomography
4. Coda-wave and noise interferometry
Passive seismic methods
for imaging structure and processes

14. Veðurstofa Íslands
Krafla
Hengill
Svartsengi
Reykjanes
IMO

15. Passive seismics tomography
(Tryggvason et al. 2003)

16. Hengill
Svartsengi
Reykjanes

17. GIPP/DEPAS

18. • Earthquake detection and analysis
Seiscomp and matlab algorithms
April 2014 – August 2015: >2000 events (P and S waves picks)
• Non-linear a priori localisation
• 1D velocity model – Velest (Kissling et al., 1994)
• 3D velocity model – Simulps (Thurber, 1986)
• Vp
• Vp/Vs ratio
Travel time tomography

19. SIL model
IMAGE
Model
1D Vp model
2050 events
(P and S picks)

20. 2014 2015
Ray paths

21. 3D Vp model
2050 events
(P and S picks)

22. W E3D Vp model
2050 events
(P and S picks)

23. 3D Vp model
2050 events
(P and S picks)
Reykjanes tip

24. 3D Vp model
2050 events
(P and S picks)
Reykjanes tip

25. Integration of methods -> better understanding
Figure from Friðleifsson et al., Geothermics 49 (2014) 119–126

26. Vp/Vs ratio
2050 events
(P and S picks)

27. Vp/Vs ratio
2050 events
(P and S picks)

28. Subsidence
~7-9 cm
InSAR
2005-2008
2014-2016
Still going on
(Friðleifsson, personal
communication;
Sigmundson, poster)Keiding et al, 2010, Fig. 5c

29. CALL FOR PAPERS
Journal of Volcanology and Geothermal Research
Special Issue: Reykjanes, Iceland
Structure and dynamics of
Mid-Oceanic Ridges geo/hydrothermal systems
• Structure and magmatic processes at mid-oceanic ridges
• Exploration and exploitation of hydrothermal systems
• Observations and modelling
• Geology, physics and chemistry of rocks and fluids
Editor in chief: Jürgen Neuberg (University of Leeds)
Editors:
Philippe Jousset (GFZ) – Philippe.Jousset@gfz-potsdam.de
Anette Kaergaard Mortensen (Reykjavik Energy) - Anette.Kaergaard.Mortensen@or.is
Kristján Ágústsson (ÌSOR) - Kristjan.Agustsson@isor.is
Prof. Magnus Tumi Guðmundsson (University of Iceland), mtg@hi.is
Guðmundur Ómar Friðleifsson (HS Orka) - gof@hsorka.is
Impact Factor: 2.674

30. The geothermal industry is different from the oil and
gas industry – opportunity for volcano scientists
Our task as researchers is to develop cheap and reliable
exploration method that the geothermal industry can afford.
◦ integration of scientific methods that come from different
horizons (volcanology, physics, chemistry, …)
◦ use of novel technologies for better knowledge of structure and
mechanisms.
EU is supporting our R&D projects to advance the development
of geothermal energy for benefits of the society.
Inspired by Olafur Flovenz (Isor)

31. Concluding remarks
The border is fading – good news!
• The Earth is the same, the objectives similar
Future resides in excellence and education, though
ambitious projects:
• Krafla Magma Testbed
• Training for future generation

32. FUTURE DIRECTIONS
Exploration and monitoring
Denser acquisition array
Accurate time measurement
Cheap technology
Example DAS technology

33. • IMO 23.03.2015 16:07:08.53
• Depth: 3.563 km
• Magnitude: 1.02Ml
• Location: Beneath Cable
P-Wave
S-Wave
1 s
>12 km

34. EAGE/DGG Workshop on
Fibre Optic Technology
in Geophysics
www.eage.org
FIRST ANNOUNCEMENT &
CALL FOR ABSTRACTS
3 1 March 2017
Potsdam, Germany
Technical Committee
Philippe Jousset Chairman (GFZ Potsdam)
Thomas Reinsch (GFZ Potsdam)
Jan Henningens (GFZ Potsdam)
Charlotte Krawczyk (T.U. Berlin)

35. FUTURE DIRECTIONS: monitoring
Monitoring of fluid and magma movements
• Multiparameter stations including superconducting gravity meters
• Deployed at volcanic site (Etna)
• To be deployed at geothermal site

36. iGrav (GWR) superconducting gravity meter
• Better performances over the whole
spectral band over other kind of gravity
meters, especially spring gravity meters.
• Badly controlled instrumental drift of spring
gravity meters a critical point preventing the
study of long-term gravity changes as
compared with the superconducting gravity
meter records.

37. Takk fyrir! Drilling at Reykjanes, March 2015
pic by Thomas Reinsch, GFZ

39. Players in the game(s)…
Developers.
Investors /Operators /Owners.
Financing institution (banks, funds).
Service companies (engineering, drilling, etc).
Manufactures.
Local and national authorities.
Public.
Environmental organizations.
Research institutions and universities
Local and national authorities.
Public.
Environmental organizations.
Research institutions and universities
Geothermal development
and industries
Volcanology and
volcanic risk management
Inspired by Olafur Flovenz (Isor)

40. • repetitious earthquakes beneath Ngauruhoe volcano (2005–2010)
• constrain the source geometry of these earthquakes by inverting waveforms for
the source location, geometry and orientation.
• The inversion and error analysis shows that a steeply dipping crack at a single
source position is the preferred model for the trigger mechanism.
• Conceptual model for Ngauruhoe earthquakes including a trigger mechanism
caused by periodic excitation of an over-pressurized cavity system, and a post
trigger resonance and scattering mechanism produced by a two phase gas–water
or gas–steam mixture.
• We explain the spectral evolution through changes in the volume fraction of
bubbles within a resonating and scattering cavity system affecting velocity,
impedance contrast, and frequency contents.

41. Vp/Vs
Resistivity
and faults
Depth
2.9 km
HENGILL, Iceland
Integration of parameters
Jousset et al., 2011, Geothermics

42. Vp/Vs
Resistivity
and faults
Depth
2.9 km
HENGILL, Iceland
Integration of parameters
Jousset et al., 2011, Geothermics

43. Classes are then mapped back to space
HENGILL, Iceland
Jousset et al., 2011, Geothermics

44. Interpretation
Class 9
(low resistivity
High VP/VS
ratio)
suggests the
existence of
supercritical
fluids at depth
below Hengill
volcano.
HENGILL, Iceland
Jousset et al., 2011, Geothermics