Retrieving the reflection events from passive seismic using Radon correlation

06 mars 2020, ISTerre Grenoble

**Séminaire de l’équipe Ondes et structures

par Diako H. Naghadeh - Dublin Institute for Advanced Studies

– Date

06 mars 2020 à 11h30

– Lieu

Salle Dolomieu, ISTerre Grenoble

Since explosive and impulsive sources such as dynamites, air guns, gas guns, even Vibroseis can have a big impact on the environment, many companies decided to record ambient noises and use it to estimate the physical properties of the subsurface. A big challenge appears when the target is extracting body waves from recorded passive signals especially in regions with the severe low-velocity weathered layer. Those waves are usually weak and surface waves are prominent in passive signals. To understand the characteristics of passive signals and the effect of natural source locations a simple two-layer synthetic model was created. A staggered finite difference method has used to solve the elasto-dynamic equations to simulate the propagation of elastic waves in that model. To extract body waves from simulated passive signals we propose and test Radon correlation that helps suppress surface waves based on the propagation velocity and amount of move out. Radon correlation is a time-spatial correlation of amplitudes on a train of Dirac delta functions through different hyperbolic paths. It is tested on synthetic 2D model data prior to its application to real recorded passive data. Synthetic tests are representing a clear body wave extraction due to applied the introduced method that cannot be seen in a general correlation result. It is possible to generate virtual shot gathers by applying Radon Correlation into a linear array of receivers and make relevant velocity model by the general processing module.