HR: 16:00h
AN: U32C-01 INVITED     [PDF]
TI: Six-years review of infrasound monitoring and studies at the French NDC
AU: * Le Pichon, A
EM: alexis.lepichon@cea.fr
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Aupetit, M
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Blanc, E
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Cansi, Y
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Guilbert, J
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Lambotte, S
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AU: Plantet, J
AF: CEA/DASE, BP12, Bruyeres-Le-Chatel, 91680 France
AB: The French NDC currently receives data from 7 IMS-type infrasound stations installed in various environments. Continuous automatic processing of the data is being performed in the [0.02-4] Hz frequency band in order to detect and characterize coherent infrasonic waves recorded on the arrays. In parallel, infrasonic background noise systematically measured in different frequency bands and correlated to local variations of wind speed, allow a geophysical monitoring of both equipment and processing results. The influence of wind-noise fluctuations on the detectability will be discussed. Examples of coherent infrasonic waves generated by strong earthquakes occurring within region of high mountains will be presented. Thorough analyses of ground-coupled air waves allow the evaluation of the relative contributions of the different source mechanisms involved in large earthquake. Using appropriate acoustic propagation models derived from realistic atmospheric profiles, the inversion of the infrasonic measurements is used to reconstruct secondary source regions. Recent developments on infrasound data processing at the French NDC concerning advanced classifier methods, propagation modeling including spatio-temporal variability of atmospheric profiles and source location procedure using multiple arrays will also be presented.
DE: 7209 Earthquake dynamics and mechanics
SC: U
MN: 2003 Fall Meeting