|
|
|
|
| |
|
|
| Herrero, A.; Murphy, Shane. |
| We propose a strategy to place a self similar slip distribution on a complex fault surface that is represented by an unstructured mesh. This is possible by applying a strategy based on the composite source model where a hierarchical set of asperities, each with its own slip function which is dependent on the distance from the asperity centre. Central to this technique is the efficient, accurate computation of distance between two points on the fault surface. This is known as the geodetic distance problem. We propose a method to compute the distance across complex non-planar surfaces based on a corollary of the Huygens’ principle. The difference between this method compared to others sample-based algorithms which precede it, is the use of a curved front at... |
| Tipo: Text |
Palavras-chave: Numerical approximations and analysis; Self-organization; Theoretical seismology. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00433/54432/55781.pdf |
| |
|
|
| 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 |
| |
|
|
| Stutzmann, E.; Ardhuin, Fabrice; Schimmel, M.; Mangeney, A.; Patau, G.. |
| The strongest seismic noise, called secondary microseisms, is generated by ocean wave interactions and we model this noise using the theory of Longuet-Higgins generalized to random ocean gravity waves. Noise sources are computed with an ocean wave model that takes into account coastal reflections. Variations of the source locations are consistent with seasonal variations of seismic noise spectra. Noise spectra are modelled over many years for stations representative of various environments such as continent, island and polar area to constrain, for each environment, the parameters involved in the modelling. For each station, we quantify the trade-off between ocean wave coastal reflection and seismic wave attenuation that both affect the amplitude of the... |
| Tipo: Text |
Palavras-chave: Surface waves and free oscillations; Theoretical seismology; Wave propagation. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00107/21839/19436.pdf |
| |
|
|
| Murphy, Shane; Herrero, A. |
| As an alternative to spectral methods, stochastic self-similar slip can be produced through a composite source model by placing a power-law scaling size-frequency distribution of circular slip dislocations on a fault surface. However these model do not accurately account for observed surface rupture behaviour. We propose a modification to the composite source model that corrects this issue. The advantage of this technique is that it accommodates the use of fractal slip distributions on non-planar fault surfaces. However to mimic a surface rupture using this technique, releasing the boundary condition at the top of the fault, we observed a systematic decrease in slip at shallow depths. We propose a new strategy whereby the surface is treated like a... |
| Tipo: Text |
Palavras-chave: Numerical approximations and analysis; Self-organization; Theoretical seismology. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71883/70580.pdf |
| |
|
|
|
