High-Frequency Directivity Effect for an Mw 4.1 Earthquake, Widely Felt by the Population in Southeastern France, - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Bulletin of the Seismological Society of America Année : 2013

High-Frequency Directivity Effect for an Mw 4.1 Earthquake, Widely Felt by the Population in Southeastern France,

F. Courboulex
A. Dujardin
  • Fonction : Auteur
M. Vallée
B. Delouis
Anne Deschamps
L. Honoré
  • Fonction : Auteur

Résumé

We document a moderate earthquake in the French Alps (26 February 2012 Mw 4.1) that has been much more distinctly felt south of the event than north of it. This discrepancy was especially clear in the two large cities of Nice and Grenoble, both situated at 100 km from the epicenter. This observation was confirmed by ground-motion measurements that were eight times larger in one city than in the other one, for the same site conditions. Using a time-domain deconvolution between the broadband recordings of the mainshock and an aftershock used as empirical Green's functions, we show that the rupture process of this event had a strong directivity effect toward a direction of N155° 5 on an ∼2 km long fault, detectable only at frequencies higher than 1 Hz. The fault size and direction are in good accordance with the location of the aftershocks. Despite the various possible contributions leading to highfrequency amplification, we show here that this simple directivity effect controlled the intensity felt by the population and the acceleration measured in the cities

Mots clés

Fichier non déposé

Dates et versions

hal-00932587 , version 1 (17-01-2014)

Identifiants

Citer

F. Courboulex, A. Dujardin, M. Vallée, B. Delouis, Ch. Sira, et al.. High-Frequency Directivity Effect for an Mw 4.1 Earthquake, Widely Felt by the Population in Southeastern France,. Bulletin of the Seismological Society of America, 2013, 103 (6), pp.3347-3353. ⟨10.1785/0120130073⟩. ⟨hal-00932587⟩
149 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More