Over the last decade, the number of research papers dealing with ambient vibration analysis methods has increased considerably. Clearly, the interest in these methods originates from both the economical attractive cost benefit ratio and the straightforward data acquisition. Being a non-destructive passive technique, these methods also complement geotechnical and/or active geophysical methods within highly populated regions.

Within the EU-SESAME, EU-SISMOVALP and NERIES projects, detailed research have been accomplished to assess the reliability and robustness of ambient vibration analysis techniques for extracting soil (site characterization) and building dynamic properties. Within this context open-source hardware and software developments have been carried out to ease the acquisition, processing and interpretation of ambient vibration wave field recordings. The main findings of these projects however show, that ambient vibration array analysis techniques have to be applied with care. It requires not only a careful measurement, but especially the interpretation and the inversion of analysis results need a (self-)critical review.

The main purpose of this course is thus to achieve the necessary understanding of the problems related to the acquisition and use of these techniques for quantitative assessments of shear-wave velocity structures and building dynamic properties. This course is targeted to students, engineers and researchers.

Contributions

This training course is:

organised by	ISTerre (Grenoble, France), NDU (Louaize, Lebanon), LU (Beirut Lebanon)
presented by	Marc Wathelet (IRD-ISTerre), Cécile Cornou (IRD-ISTerre), Bertrand Guillier (IRD-ISTerre), Christelle Salameh (NDU-ISTerre), Jacques Harb (NDU), Dalia Youssef Abdel-Massih (LU), Yara Maalouf (NDU).

The software development (was) is supported by NERIES (EU-Project, 2006-2010), SESAME (EU-Project, 2001-2004) , Sismovalp (Interreg IIIB, Alpine Space, 2004-2006), EPOS-IP (EU-Project), IRD

Course outline

This is a program which may be subject to slight changes in the future.

Monday
09:00-09:30	Course opening ceremony
	Technical issues and program overview
09:30-10:45	Principles of seismic wave propagation	Lecture
	Focus on surface waves properties. The linkage between subsurface structure and wave field propagation properties: relationships between site conditions, Rayleigh ellipticity, dispersion curves of surface waves and SH transfer function
10:45-11:00	Coffee break
11:00-12:30	Signal processing basics	Lecture
	A/D sampling problem, instrument transfer function. Spectral analysis, Fast Fourier Transform, Power Spectrum.
12:30-14:00	Lunch break
14:00-15:30	Introduction to Geopsy software package I	Exercise
	Presentation of Geopsy.org modules Using graphics concept in Geopsy.org software package Plotting graphics, importing and exporting layers, makeups, etc.
15:30-15:45	Coffee break
16:00-17:30	Introduction to Geopsy software package II	Exercises
	Starting Geopsy, opening existing & storing databases Import and export of signals, waveform tools (filter, FFT, ...) Views, editing and manipulating header entries, sorting, grouping, importing coordinates
Tuesday
9:00-10:30	Ambient vibration wavefield	Lecture
	State of the art about the nature of the ambient vibration wave field. Review of world-wide studies using ambient vibrations for site characterization and buildings.
10:30-10:45	Coffee break
10:45-12:30	Single-station ambient vibration method for extracting soil and building dynamic properties	Lectures
	Computation and interpretation of horizontal to vertical spectral ratio technique (H/V) Effects of experimental conditions, recommendations for field measurements Computation and interpretation of ambient noise measurements for buildings: resonance frequencies, damping, modal shape
12:30-14:00	Lunch break
14:00-15:30	Single station measurement, H/V	Exercises
	Geopsy tools for H/V. Field data examples.
15:30-15:45	Coffee break
16:15-18:00	Extracting building dynamic properties	Exercises
	Geopsy tools for buildings Field data examples (resonance frequencies, damping, modal shape).
Wednesday
9:00-10:45	Basic array processing concepts (conventional and high-resolution frequency wavenumber, f-k)	Lecture
	Overview array processing methods. The intuitive shift-and-sum technique in time domain and its transposition into the frequency wavenumber (f-k) domain. Discrete spatial sampling of the continuous seismic wave field (by small groups of seismic stations - arrays) : concepts of resolution and aliasing. Resolution and aliasing of simple linear array layouts and generalisation to bi-dimensional array settings. Relation between array geometry and resulting estimation capabilities: rules of thumb and the array response function. Background of a widely used method, the high resolution f-k method after Capon (1969).
10:45-11:00	Coffee break
11:00-12:30	Conventional and high-resolution f-k processing	Exercises
	Building experience on how modifications in array layout affect the measurable wavelength range.
12:30-14:00	Lunch break
14:00-16:00	Conventional and high-resolution f-k processing	Exercises
	Application of the conventional and high-resolution f-k algorithms to estimate the dispersion curves.
16:00-16:15	Coffee break
16:15-17:45	Active surface waves technique (MASW)	Lecture and exercises
	The SASW, MASW and passive linear array techniques: theory, acquisition, processing and resolution limits. Demonstration of MASW application
Thursday
08:30-09:00	Lebanon from a seismic risk perspective	Lecture
	Geological structures Historical seismicity Building vulnerability
09:15-10:45	Preparation of the field experiment	Lecture
	Presentation of WARAN (wireless array network) equipment. Presentation of the active seismic equipment.
11:00-18:00	Field experiment	Field
	Field experiment in Byblos downtown (noise array, MASW and building measurement) and lunch boxes !.
19:00-...	Workshop Dinner
Friday
9:00-10:45	Spatial autocorrelation method (SPAC)	Lecture and Exercises
	Background of the spatial autocorrelation technique (SPAC) introduced by Aki (1957). Application and comparison with FK estimates: advantages and limitations of each approach
10:45-11:00	Coffee break
11:00-12:30	Dispersion curve inversion	Lecture
	Short introduction to the fundamentals of inversion theory. Direct and global search methods based on a random sampling, and particularly the Neighbourhood algorithm. Specific issues solved for the inversion dispersion curves: robustness of the forward computation, non-uniqueness of the final solution.
12:30-14:00	Lunch break
14:00-15:45	Dispersion curve inversion	Exercises
	Introduction to dinver software Inversion of theoretical dispersion curve in order to identify critical issues. Model parameterisation and parameter range (vP, vS). Discussion of inversion results: what do we get ? Handling shear-wave profiles: extraction of usefull engineering parameters (e.g. Vs30).
15:45-16:00	Lunch break
16:00-17:30	Processing field data.	Exercises
	Analysis of the signals recorded on the field with H/V and MASW techniques.
Saturday
09:00-10:45	Processing field data.	Exercises
	Analysis of the signals recorded on the field with f-k, high-resolution f-k, SPAC techniques.
10:45-11:00	Lunch break
11:00-12:30	Processing field data.	Exercises
	Analysis of the signals recorded on the field with f-k, high-resolution f-k, SPAC techniques. Combining dispersion estimates from passive and active techniques.
12:30-14:00	Lunch break
14:00-15:45	Processing field data.	Exercises
	Decision on the usable frequency range for the inversion target. Inversion of the dispersion curve
15:45-16:00	Coffee break
16:00-18:00	Processing field data.	Exercises
	Extraction of engineering parameters (e.g. Vs30). Comparison of the individual results obtained during the inversion. General discussion of experience gained during this complete test. Summary of the various steps involved for the task of ambient vibration array and MASW analysis and site characterisation by the inversion of one-dimensional earth models.
Sunday
09:00-12:00	Entertainment and open discussion
	Open discussion on the scientific and technical problems encountered by participants. Visit of the Jeita cave.

Suggested readings

• Aki, K. (1957). Space and time spectra of stationary stochastic waves, with special reference to microtremors, Bull. Earthq. Res. Inst. 35, 415-456.
• Bard, P.-Y. (1999). Microtremor measurements: a tool for site effect estimation?, State-of-the-art paper, 2nd International Symposium on the Efects of Surface Geology on Seismic Motion, Yokohama, Balkema, 3, 1251--1279.
• Bettig, B., P.-Y. Bard, F. Scherbaum, J. Riepl, F. Cotton, C. Cornou and D. Hatzfeld (2001). Analysis of dense array noise measurements using the modified spatial auto-correlation method (SPAC). Application to the Grenoble area., Bolletino di Geofisica Teorica ed Applicata 42, 281-304.
• Capon, J. (1969). High-resolution frequency-wavenumber spectrum analysis, Proc. IEEE 57, 1408-1418.
• Sambridge, M. (1999a). Geophysical inversion with a neighbourhood algorithm: I. Searching a parameter space, Geophys. J. Int. 138, 479-494.
• Sambridge, M. (1999b). Geophysical inversion with a neighbourhood algorithm: II. Appraising the ensemble, Geophys. J. Int. 138, 727-746.
• Tokimatsu, K. (1997). Geotechnical site characterization using surface waves, In Proc. 1st Intl. Conf. Earthquake Geotechnical Engineering, Ishihara (ed), Balkema, 1333-1368.
• Cornou, C., M. Ohrnberger, D. M. Boore, K. Kudo, P.-Y. Bard (2006). Using ambient noise array techniques for site characterisation: results from an international benchmark, in Proc. 3rd Int. Symp. on the Effects of Surface Geology on Seismic Motion, Grenoble, 29 August - 01 September, 2006, Bard, P.Y., Chaljub, E., Cornou, C., Cotton, F. and Guéguen, P. Editors, LCPC Editions, paper NBT. pdf
• Wathelet, M., D. Jongmans, M. Ohrnberger, and S. Bonnefoy-Claudet (2008). Array performances for ambient vibrations on a shallow structure and consequences over Vs inversion, Journal of Seismology , 12(1) , 1-19. pdf
• Wathelet M. (2008). An improved neighborhood algorithm: Parameter conditions and dynamic scaling, Geophysical Research Letters , 35(9) , 26-30.pdf

All deliverables and reports of the SESAME project are available here (especially, D18.06, D19.06, D24.13 may be of interest).

Registration and Fees

This course aims at transfering and promoting scientific and technical achievements of current and past research projects. This course is targeted to students, engineers and scientists with a background in signal processing for geophysical/seismological applications. The official language is English.

Online registration is open until June 15^th 2016. If the number of applicants is larger than 20, the organizers reserve their rights to select the participants who will be informed by June 22^nd.

The course will take place at NDU, Louaize, Lebanon. The registration fee is fixed to 800 USD per participant. The fees include all expenses related to tuition, training, support material, field experiment, workshop dinner, lunches and coffee breaks during the course.

A limited number of grants are available to support the registration fee and/or travel expenses of selected participants, with priority given to students working in a developing country.

Participants are requested to attend the course with their own laptop, if possible. In such a case they are requested to indicate their operating system (windows/linux/mac-elcapitan) during the online registration.

A list of suggested accommodations will be available soon.

Contacts

Cécile Cornou	cecile dot cornou at univ-grenoble-alpes dot fr
Bertrand Guillier	Bertrand dot Guillier at ird dot fr
Marc Wathelet	marc dot wathelet at univ-grenoble-alpes dot fr
Jacques Harb	jharb at ndu dot edu dot lb
Dalia Youssef Abdel-Massih	Dalia.Abdelmassih at ul dot edu dot lb

Archives

Here you can find the program of last editions and all photos taken during these courses:

• Grenoble, November 2005: program, photos (thanks to Sylvette Bonnefoy, Mehmet Ergin, Fabrizio Cara and Carlo Cauzzi).
• Berlin, April 2006: program
• Caracas, October 2006: program, photos (thanks to Victor Rocabado).
• Algiers, July 2007: program
• Bangalore, November 2007: program
• Istanbul, May 2008: program
• Thessaloniki, December 2008 program
• Thessaloniki, February 2010 program
• Las Vegas, February 2012 program
• Grenoble, February 2014 program