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A Laboratory Carefully Located on a Fault Line

The Corinth Rift Geodynamic Laboratory

The Helike Fault: a trench for studying geological layers.

The CNRS is partner to the development of a European in situ Laboratory of Geodynamics in the Gulf of Corinth, in Greece. Its objective? A better understanding of the interactions between fluids and the seismic behavior of active faults through the use of recordings made on the surface and at various depths.

“When we attempt in a laboratory to investigate the mechanical behavior of seismogenic faults, the values are not right. Our models do not reproduce what we find out in the field, and especially when it comes to heat exchange.” François-Henri Cornet is head of the Laboratory of Rock Mechanics at Paris' Institute of Physics of the Globe (IPG-P) which is one of the participating laboratories1 in a bold European project to operate a geodynamics laboratory in the heart of a rift.2

Surface de glissement

© Cornet, IPG-P, Laboratoire de mécanique des roches

Slide plane within a fault zone as seen in a core sample.


Corinth, a unique site for study
The Corinth Rift (central Greece) is the fastest widening rift in the world, at 1cm per year. The south coast of the Gulf, near the city of Aigion, was chosen as the site for this new type of laboratory, because it represents one of the most active seismic zones in all Europe. Aigion was shaken by an earthquake of magnitude 6.2 in 1995, the fifth event of this magnitude in thirty years for the Corinth gulf.

Core drilling on active fault lines
The Corinth Rift Laboratory (CRL) has been set up for the purpose of making continuous seismometric and satellite observation both at the surface and deep below. The latter is a delicate assignment, requiring drilling through active zones. The bore wells provide not only core samples but also a way to place recording instruments in the immediate vicinity of the fault. Drilling also makes it possible to bring up water samples for geochemical analysis.
With installation completed, a 1,000 meter bore well runs down through the Aigion fault, and seismic probes are in place for an ongoing study that will last five or six years, according to François-Henri Cornet.

Maison inhabitable

© CNRS, Christophe Berthod

Uninhabitable building in the center of Aigion.


Interaction between fault mechanics and fluids
The major CRL project consists of collecting data on the influence of fluids in general and water in particular on the behavior of faults and, inversely, data on the effects of fault activity on the local hydro-geology. As it turns out, specialists in this area lack the direct observation data they need to spell out the real effect of fluid pressure at times of rupture as well as the phenomenon of fault healing.
Dr. Cornet's team is not, however, limiting its ambition to only these objectives; they aim to drill to a depth of 5,000 meters to observe what happens in what is truly the heart of the seismic zone.


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Summary

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Proceedings of the 1st workshop on the development of a multiborehole observatory at the Gulf of Corinth.
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corinth-rift-lab

Contact

François-Henri Cornet
Département de sismologie
CNRS-IPG Paris
Université Paris VII
Tel: +33 (0) 01 44 27 38 97
E-Mail: cornet@ipgp.jussieu.fr

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ipgp.jussieu/sismo

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corinth-rift-lab

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ipgp.jussieu/mecaroc

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dt.insu/corinth

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