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Archive COGEAR: Coupled Seismogenic Geohazards in Alpine Regions

COGEAR was an interdisciplinary natural hazards project investigating the hazard chain induced by earthquakes. It addressed tectonic processes and the related variability of seismicity in space and time, earthquake forecasting and short-term precursors, and strong ground motion as a result of source and complex path effects.

We studied non-linear wave propagation phenomena, liquefaction and triggering of landslides in soils and rocks, as well as earthquake-induced snow avalanches. The Valais, and in particular parts of the Rhone, Visper and Matter valleys have been selected as study areas. Tasks included detailed field investigations, development and application of numerical modelling techniques, assessment of the susceptibility to seismically induced effects and installation of different monitoring systems to test and validate our models. These systems are for long-term operation and include a continuous GPS and seismic networks, a test installation for observing earthquake precursors, and a system to study site-effects and non-linear phenomena in two test areas (Visp, St. Niklaus-Randa). Risk-related aspects of impacts on buildings and lifelines were also considered.

COGEAR was supported by the Competence Center for Environment and Sustainability (CCES) of ETH Zurich.

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Area of interest (Rhone valley, Visp, Visper Valley - view to south), red color denotes the settled areas, yellow color denotes the industrial area.

Earthquakes in Switzerland seriously threaten society and human beings (KATARISK, 2003). Although damaging earthquakes are rare when compared to more seismically active regions, such events have occurred and will continue to do so. Over the past 700 years, a total of 28 events of a moment magnitude Mw≥5.5 are known, twelve of which caused severe damage (Intensity of VIII or higher).

Moderate to high seismic risk in Switzerland results from high population density and high degrees of industrialization, as well as from low preparedness. Since earthquakes strike generally without warning and exhibit relatively long return periods of strong ground shaking, the best preparation modern society can achieve is to upgrade the building stock, infrastructure and critical facilities so that damage is minimized. The input for all measures of risk mitigation is assessment of the different hazards associated with earthquakes through advanced technology.

The Valais is the area of greatest seismic hazard in Switzerland and has experienced a magnitude 6 or larger event every 100 years (1524, 1584, 1685, 1755, 1855, 1946), with the last magnitude 6.1 earthquake in 1946 close to Sion and Sierre (Figure 1). This area and in particular the region of Visp hold special interest: on average the Visp region has been struck by damaging earthquakes every 40 years (Intensity VI-VIII), with the last in 1960 reaching a macroseismic intensity of VIII. The Visp event of 1855 was the largest in Switzerland for the last 300 years. Besides its seismic activity, the test area in the Valais is characterized by several factors adding to the total hazard level: rough topography, unstable and steep slopes, deep sediment-filled valleys, and wide glacier- and snow-covered areas. On the one hand, during the Brig event (Mw=6.1) in 1755, the Visp event in 1855 (Mw=6.4) and the Sion/Sierre event in 1946 (Mw=6.1) the area experienced great damage from earthquake ground motion and different secondary phenomena such as liquefaction in the Rhone plain, landslide reactivation and extended rock fall. On the other hand, we expect that smaller and more frequent earthquakes induce large ground motions locally, as well as small-scale movements and failures on critically stressed slopes. Earthquakes also degrade rock mass strength and thus add to landslide preparation.

Due to river regulations and engineering progress in the last two centuries, seismically unfavourable sites have become attractive for expanded settlement and industries. During the last century, many villages grew into the Rhone plain and expanded near hazardous slopes in the valleys. They are still growing. Future earthquakes will therefore cause more damage than was observed in the past. For this reason we must recognize and map potential areas, estimate ground motion and non-linear behaviour for engineers and planners, and provide adequate estimates for the building code.

Motivation
Large earthquakes in the Valais and the timing of magnitude 6 or larger historical events.

While predicting damaging earthquakes remains currently impossible, it is important to lay a solid foundation for improving our ability to forecast them. Although the Visp area shows only moderate seismicity on a worldwide scale, the region offers an excellent opportunity to observe and study the preparation processes for a moderate to large event in the Alpine collision zone. The probability of observing a major earthquake in the next 40 years is high and the proposed project is a first step in studying its preparation. Moreover, it will allow us to set up a scientific base for detailed monitoring and analysis. Due to the limited size of the area where the next large earthquake in the Valais might occur, this region is one of the best natural observatories in Europe. To ongoing surveillance and seismic hazard assessment, the proposed project therefore adds two new elements: 1) interdisciplinary investigation and monitoring of short and long-term earthquake preparation processes at a regional scale, and 2) study of complex non-linear surface effects induced by seismic strong ground motion at a local scale.

COGEAR proposes research with a long-term perspective, including a follow-up study that will focus on assessing risk. The monitoring system is key. It is focused on the Valais and in particular on the epicentral areas of the 1755 and 1855 earthquakes, including the Rhone river plain at Visp and the Visper and Matter valleys. The following networks and sites are proposed in the project COGEAR:

  1. A dense regional network for monitoring crustal deformation, seismicity and possible active faults (entire Valais), including seismic stations in boreholes;
  2. Local strong-motion networks for monitoring earthquake ground motion and 3D site-effects at Visp and St. Niklaus;
  3. Test sites for studying site effects, non-linear phenomena in liquefiable soils and related pore pressure effects (Visp);
  4. Test sites on landslides to study site effects and dynamic loading of landslides in relation to topography, geological disposition, kinematics and (static/dynamic) slope stability (Matter valley);
  5. Installations, including electromagnetic and geo-chemical sensors, to monitor possible short-term precursors of earthquakes.
  6. Seismic monitoring of buildings in the Visp area.

Such a monitoring system will be innovative for the Swiss as well as the international scientific community, and will provide data of unique value and quality. We expect that these systems will be operational for many decades, with a high probability that they will monitor the next damaging earthquake in the Valais.

Module 1: Coordination and Data Integration (Leader: Fäh)

The purpose of this module is to manage all modules, serve as an interface between them, and provide a common geo-referenced GIS-platform and remote sensing data. A deliverable of this module is a database of observed earthquake effects in the Valais as well as quantification of secondary hazards from large earthquakes based on worldwide observation. Module 1 coordinates the joint monitoring systems installed in the different modules. An additional objective is to develop and integrate new sensor types, wireless communication systems and self-locating sensors in centralized mobile multi-sensor networks.

The sub-modules are:

  1. Overview of earthquakes effects (Leader: Korup, Gisler / Main partners: SLF, SED)
  2. Database and GIS platform (Leader: Hurni / Main partners: IKA, PRS, SED)
  3. Vulnerability and risk (Leader: Lestuzzi / Main partners: IMAC, IBK)
  4. Hazard scenarios (Leader: Laloui, Lestuzzi, Fäh / Main partners: LMS, IGT, SED, IMAC)

 

Module 2: Earthquake preparation (Leader: Jonsson, Geiger)

Within Module 2 we establish local geodetic and seismic monitoring networks. Such monitoring will detect and quantify inter-seismic strain-rates in the Valais, connect this information with observed faulting styles to understand temporal changes in earthquake activity for forecasting, and observe possible short-term precursors as well as post-seismic motion. A revision of the seismo-tectonic framework of the Valais will be carried out and scaling relations developed to allow for ground motion simulations of potential earthquakes. In module 2, ground motion modeling will focus on the influence of complex source properties and wave propagation in the crust.

The sub-modules are:

  1. Seismicity, deformations and active faults (Leader: Jonsson / Main partners: SEG, SED, GGL)
  2. Geodetic measurements and kinematic modelling (Leader: Geiger / Main partners: GGL, SEG, SED)
  3. Long-term earthquake hazard assessment and forecasting (Leader: Wiemer / SED)
  4. Short-term earthquake precursors (Leader: Huang, Fäh / SED)

 

Module 3: Complex surface phenomena (Leader: Löw, Laue)

Module 3 studies wave propagation phenomena in complex surface structures. Local strong-motion networks and novel geotechnical monitoring systems will be installed. These systems will monitor near-field and complex site effects, related pore pressure effects and non-linear phenomena in liquefiable soils and fractured rocks (Visp and the Matter Valley). Through monitoring, modeling and susceptibility analysis, we will compare how long and short-term seismic loading and cyclic climatic effects (such as snow melt and heavy precipitation) affect slope stability. The monitoring systems will provide data to verify the results of the numerical modeling. The sub-modules are:

  1. Non-linear soil behavior and liquefaction in alluvial sand deposits (Leader: Laue, Fäh / Main partners: IGT, SED, AUG, IMAC)
  2. Topographic effects and non-linear behavior of rock and soil slopes (Leader: Löw, Laloui / Main Partners: EngGeo, LMS, SED)
  3. Earthquakes and snow avalanches (Leader: Rhyner, Fäh / Main partners: SLF, SED)

Project coordinator:

Prof. Dr. Donat Fäh, Swiss Seismological Service, ETH Zürich

 

Principal investigators:

Prof. Dr. Simon Löw, Engineering Geology, ETH Zürich

Prof. Dr. Alain Geiger, Institute of Geodesy and Photogrammetry, ETH Zürich

Prof. Dr. Lorenz Hurni, Institute of Cartography, ETH Zürich

Dr. Jan Laue, Institute of Geotechnical Engineering, ETH Zürich

Prof. Dr. Lyesse Laloui, Soil Mechanics Laboratory, EPF Lausanne

Dr. Jürg Schweizer, Swiss Federal Institute of Snow and Avalanche Research

Dr. Luis Dalguer, Seismology and Geodynamics, ETH Zürich

Prof. Dr. Hansruedi Maurer, Applied and Environmental Geophysics, ETH Zürich

Dr. Pierino Lestuzzi, Applied computing and Mechanics Laboratory, EPF Lausanne

Dr. Manos Baltsavias, Institute for Geodesy and Photogrammetry, ETH Zürich

 

Sub-module leaders:

Prof. Donat Fäh (1d, 2d, 3a, 3c), SED ETHZ

Prof. Alain Geiger (2b), GGL ETHZ

Dr. Monika Gisler (1a), SED ETHZ

Prof. Donat Fäh (2d), UP / SED ETHZ

Prof. Lorenz Hurni (1b), IKA ETHZ

Dr. Luis Dalguer (2a), SEG ETHZ

Dr. Oliver Korup (1a), SLF

Prof. Lyesse Laloui (3b), LMS EPFL

Dr. Jan Laue (3a), IGT ETHZ

Dr. Pierino Lestuzzi (1c, 1d), IMAC EPFL

Prof. Simon Löw (3b), EngGeo ETHZ

Dr. Jürg Schweizer (3c), SLF

Dr. Stefan Wiemer (2c), SED ETHZ

 

Swiss Seismological Service, ETH Zürich

Sonia Alvarez-Rubio, Gregory Anderson, Corinne Bachman, Sascha Barman, Cyrill Baumann, Falko Bethemann, Jan Burjánek, John Clinton, Nicholas Deichman, David Eberhard, Benjamin Edwards, Fabian Euchner, Donat Fäh, Stefan Fritsche, Daniel Gilgen, Monika Gisler, Roland Grimmer, Florian Hasslinger, Stephan Husen, Philipp Kästli, Toni Kraft, Stefano Marano, Iris Marschall, Michael Meier, Clotaire Michel, Valerio Poggi, Javier Revilla, Gabriela Schwarz-Zanetti, Seok Goo Song, Anne Sornette, Mateo Spada, Gabriela Gassner-Stamm, Robert Tanner, Michael Wagner, Stefan Wiemer, Jochen Woessner, Alba Zappone, Peter Zweifel

 

Engineering Geology, ETH Zürich

Werner Balderer, Edward A. Button, Franziska Dammeier, Valentin Gischig, Jeffrey Moore, Kerry Leith ,Simon Löw, Reto Seifert, Freddy Yugsi

 

Geodesy and Geodynamics Lab, ETH Zürich

Alain Geiger, Simon Häberling, Hans-Gert Kahle, Albin Kretz, Philippe Limpach, Paul Sorber, Arturo Villiger

 

Institute of Cartography, ETH Zürich

Crisitna Iosifescu, Ionut E. Iosifescu, Lorenz Hurni, Claudia Matthys, Olaf Schnabel

 

Institute of Geotechnical Engineering, ETH Zürich

Anita Abt, Ernst Bleiker, Richard Eyer, Ralf Herzog, Jan Laue, Alexandru Marin, Sarah Springman, Benjamin Wäffler, Sonja Zwahlen

 

Photogrammetry and Remote Sensing, ETH Zürich

Armin Grün, Emmanuel Baltsavias, Henri Eisenbeiss, Charis Papasaika, Martin Sauerbier

 

Soil Mechanics Laboratory, EPF Lausanne

Li Chao, Fabrice Dupray, John Eichenberger, Suzanne Fauriel, Alessio Ferrari, Lyesse Laloui

 

Swiss Federal Institute of Snow and Avalanche Research

Perry Bartelt, Mathias Bavay, Oliver Korup, Michael Lehning, Stefan Margreth, Jakob Rhyner, Mark Schaer, Jürg Schweizer

 

Seismology and Geodynamics, ETH Zürich

Luis Angel Dalguer, Stephan Husen, Sigurjón Jónsson, Edi Kissling, Martin Mai, Michael Wagner, Yaming Wang

 

Applied and Environmental Geophysics, ETH Zürich

Hansruedi Mauer, Jan Van der Kruk

 

Applied computing and Mechanics Laboratory, EPF Lausanne

Amin Karbassi, Pierino Lestuzzi, Marcelo Oropeza

 

Institute of Structural Engineering, ETH Zürich

Alessandro Dazio

 

Swiss Experiment

Philipp Schneider, Nicholas Dawes

 

Other Partners

Qinguah Huang (University of Peking), Adrian Wiget (SwissTopo), Blaise Duvernay (BAFU)

General Meetings:

COGEAR Forth-Year General Meeting, Visp, Wednesday to Friday 25-27, January 2012.

COGEAR Third-Year General Meeting, Visp, Wednesday to Friday 26-28. January 2011.

COGEAR Second-Year General Meeting, Visp, Wednesday to Friday 27-29. January 2010.

COGEAR First-Year General Meeting, Visp, Wednesday to Friday 28-30. January 2009.

COGEAR Kick-off Meeting, Zürich, January 28, 2008.

 

Special Meetings:

Informations-Veranstaltung zum Thema  Erdbeben im Wallis, Special workshop held during COGEAR Third-Year General Meeting in Visp, Thursday 27, January 2011.

 

Module Meetings:

Module 1a

  • 1. April 2008, Zürich: Coordination, milestones and deliverables of tasks (Monika Gisler).

 

Module 1b

  • 28. February 2008, Zürich: Necessary data and data schemes (Olaf Schnabel).
  • 19. August 2008, Zürich: Definition of Database and Interfaces General Meeting for all Tasks, Joint meeting with SWISS Experiment.
  • 18. December 2008, Zürich (9:00 IKA, HIL - Hönggerberg): The status of the COGEAR database and the next steps. 
  • 1. July 2009, Lausanne: Database & Instrumentation, joint meeting with SWISS Experiment (Pierino Lestuzzi, Clotaire Michel).
  • March 2010, Zürich: Technical meeting (GSN, sensor data), joint meeting with SwissEx (Florian Hasslinger).

 

Module 2b

  • 3. July 2008, Zürich: Collocation of GPS and seismic
    stations (Alain Geiger).

 

Module 2d

  • 8. May 2008, Zürich: Short Term Earthquake Precursors.

 

Module 3a

  • 18. December 2008, Zürich (13:30 - 15:00 , HIT K 52 - Hönggerberg): Project-work presentations: Seismische Standortanalyse in alpinen Tälern - Visp (by Benjamin Wäfler); Seismische Standortanalyse in alpinen Tälern -St. Niklaus (by Richard Eyer).

 

Module 3b

  • 4. June 2008, Zürich (9:00, Hoenggerberg): Organizing the field measurements at Randa (Edward Button).
  • March 2010, Zürich: Soil samples from the Grächen site (Jeff  Moore).
  • March/April 2010, Zürich: Randa site, general meeting - next steps (Jeff  Moore).

 

Module 3c

  • 20. November 2008, Davos (11:00, SLF): Earthquakes and snow avalanches (Mark Schaer).

Peer reviewed papers:

Download PDF

 

Conference papers, thesis and reports:

Download PDF

 

Presentations:

Download PDF

 

Deliverables (Reports):

Module 1

  • Deliverable 1b.1.2 Integration of remote sensing data for the Visp area and Matter Valley.
  • Deliverables 1c.1.1 & 1c.1.2 Validate the building inventory and important. infrastructure in the test area & Development of theoretical fragility functions.

 

Module 2

  • Deliverable 2a.3 Earthquake Ground Motion Simulation (Kinematic and dynamic rupture models).
  • Deliverable 2c.1 Developing new approaches for time-dependent hazard assessment and forecasting.

 

Module 3

  • Deliverable 3.1.1 (MSc. thesis) Joint inversion of surface waves and refracted P- and S-waves.
  • Deliverable 3.3.1 Comparison between measurement techniques at sites   investigated by AUG and SED.
  • Deliverable 3a.4.3.1 (MSc. thesis) Modelling of Non-Linear Phenomena - Dynamische Analyse des Lonza Areals in Visp.
  • Deliverable 3a.4.3.2 Modelling of Non-Linear Phenomena - Soil-Structure Interaction in Alpine Valleys.
  • Deliverable 3b.1.2 Topographic effects and non-linear behavior of rock and soil slopes  - Installation of semi-permanent seismic array and data analysis.
  • Deliverable 3b.1.3.2 Instrument evaluation, site selection, and installation of permanent instrumentation.
  • Deliverable 3b.2.5 (Ph.D. thesis - chapter) Development of a 3D model of the Matter valley.