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| Courboulex, Francoise; Mercerat, E. Diego; Deschamps, Anne; Migeon, Sebastien; Baques, Marion; Larroque, Christophe; Rivet, Diane; Hello, Yann. |
| A broadband seismological station (PRIMA) installed offshore Nice airport (southeastern France) reveals a strong amplification effect of seismic waves. PRIMA station was in operation for 2 years (9/2016 to 10/2018) on the outer shelf at a water depth of 18 m. Situated at the mouth of the Var River, this zone is unstable and prone to landslides. A catastrophic landslide and tsunami already occurred in 1979, causing 10 casualties. Given the level of seismicity of the area, it is important to infer the impact of an earthquake on this zone. We analyze the recordings of earthquakes and seismic noise at the PRIMA station by comparing them to nearby inland stations. We find that the seismic waves are strongly amplified at PRIMA at some specific frequencies (with... |
| Tipo: Text |
Palavras-chave: Earthquakes; Site effects; Landslides; Offshore seismometer; Seismic hazard. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00659/77081/78405.pdf |
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| Ioualalen, Mansour; Ratzov, G.; Collot, Jean-yves; Sanclemente, E.. |
| P>Shelf promontories exhibit very specific bathymetric features with regards to tsunamis. Because of their submerged cape morphology, a potential tsunami generated seawards of the promontory will exhibit a specific mode of propagation and coastal impact. To identify this peculiar tsunami signature, the Atacames Promontory, Ecuador, was chosen as a case study (another example is the shelf of the Nile delta, Egypt). The area is tectonically very active, hosts earthquakes among the most powerful recorded, as well as areas of slope instabilities that have triggered significant submarine landslides in the past (several cubic kilometres of volume). Both types of events are likely to be tsunamigenic. To examine the tsunami behaviour at the coastal area of the... |
| Tipo: Text |
Palavras-chave: Tsunamis; Site effects; Wave propagation; Submarine landslides; South America. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00200/31101/29509.pdf |
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| Gualtieri, Lucia; Stutzmann, Eleonore; Farra, V.; Capdeville, Y.; Schimmel, M.; Ardhuin, Fabrice; Morelli, A.. |
| Secondary microseismic noise is generated by non-linear interactions between ocean waves at the ocean surface. We present here the theory for computing the site effect of the ocean layer upon body waves generated by noise sources distributed along the ocean surface. By defining the wavefield as the superposition of plane waves, we show that the ocean site effect can be described as the constructive interference of multiply reflected P waves in the ocean that are then converted to either P or SV waves at the ocean-crust interface. We observe that the site effect varies strongly with period and ocean depth, although in a different way for body waves than for Rayleigh waves. We also show that the ocean site effect is stronger for P waves than for S waves. We... |
| Tipo: Text |
Palavras-chave: Body waves; Site effects; Theoretical seismology. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00190/30087/28634.pdf |
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