We propose a 2 months internship in statistics to study the spatial variability of ground motion in Cephalonia, Greece. A detailled description of the project can be found below. 

The successful candidate should be a master student in statistics. (S)he will be based in LTHE, Grenoble, France. 

Start date can extend from August to November. Salary will be around 500 euros/month according to French law.

For more information, please contact Juliette Blanchet, [log in to unmask]

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Statistical study of the spatial variability of ground motion characteristics

Assessing the vulnerability of residential houses or industrial facilities to earthquakes is a current issue. Ground motion is measured by accelerograms and is characterized by a seismic scenario (moment magnitude, hypocentral distance, soil condition). Common ground motion indicators are the peak ground acceleration, Arias intensity, duration, central frequency, frequency bandwidth… Those characteristics are measured at individual locations and linking them together in order to better understand how ground motion propagates in space is still an open question. For this, a better understanding of how ground motion characteristics are both spatially correlated and intrinsically variable is needed.

The project FP EU-NERA (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation, 2010-14) aims at better understanding key parameters that locally control the ground motion spatial variability. In this framework, a large seismological experiment took place in the high seismicity area of Cephalonia (Greece). 22 seismological stations were distributed along a profile crossing the valley with interstation distance of about 50 m in order to thoroughly capture spatial variation of ground motions with distance from the basin edge. This network also included two very dense arrays located close to the basin edge and in the basin center for spatial variability and differential motion studies at a very local scale. 
First empirical analyses showed a large variability of ground motion parameters even at small scale. This project aims at going further in assessing this variability by conducting an integrated statistical analysis. First step will be to perform an explanatory analysis in order to validate the data. Second step will aim to estimate this variability using geostatistical tools such as theoretical variograms in different directions. This will help assessing wether ground motion variability differs from one direction to another and understanding the geophysical reasons for that.

This work will be performed throughout a collaboration between LTHE (Laboratory for the study of Transfers in Hydrology and Environment), 3S-R (Soils, Solids, Structures - Risks Laboratory) and ISTerre (Institute of Earth Sciences).

Keywords: spatial variability, geostatistics, ground motion, seismic signal.

Scientific advisors:
J. BLANCHET, A.-C. FAVRE-PUGIN
Laboratory for the study of Transfers in Hydrology and Environment (LTHE)
Domaine universitaire, BP 53, 38041 Grenoble Cedex 9, FRANCE
Contact: [log in to unmask]
             [log in to unmask] 

J. BAROTH, F. DUFOUR
Soils, Solids, Structures - Risks Laboratory (3S-R)
Domaine Universitaire, BP 53, 38041 Grenoble Cedex 9, FRANCE
Contact: [log in to unmask]

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