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Accueil du site > Séminaires, conférences > Séminaires du LIP > Séminaires en 2014-2015 > Léonard Seydoux (Institut de Physique du Globe de Paris), invité par J.G. Minonzio

Léonard Seydoux (Institut de Physique du Globe de Paris), invité par J.G. Minonzio

Orateur : Léonard Seydoux (Institut de Physique du Globe de Paris)

Titre : Detecting Seismic Activity with a Covariance Matrix Analysis of Data Recorded on Seismic Arrays

Résumé : Modern seismic networks are recording the ground motion continuously all around the word, with very broadband and high-sensitivity sensors. The aim of our study is to apply statistical array-based approaches to processing of these records. We use the methods mainly brought from the random matrix theory in order to give a statistical description of seismic wavefields recorded at the Earth’s surface. We estimate the array covariance matrix and explore the distribution of its singular values that contains information about the coherency of the sources that generated the studied wavefields. With this approach, we can make distinctions between the signals generated by isolated deterministic sources and the « random » ambient noise. We design an algorithm that uses the distribution of the array covariance matrix singular values to detect signals corresponding to coherent seismic events. We investigate the detection capacity of our methods at different scales and in different frequency ranges by applying it to the records of two networks : (1) the seismic monitoring network operating on the Piton de la Fournaise volcano at La Réunion island composed of 21 receivers and with an aperture of ∼15 km, and (2) the transportable component of the USArray composed of ∼100 receivers with ∼70 km inter-station spacing.