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It is called "antipodal focusing". See for example Antipodal focusing of seismic waves observed with the USArray. We present an analysis of the M-w = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in ...


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The article can be found here in Geophysical Research Letters: Fan, W., McGuire, J. J., Groot‐Hedlin, C. D., Hedlin, M. A. H., Coats, S., & Fiedler, J. W. ( 2019). Stormquakes Geophysical Research Letters, 46. https://doi.org/10.1029/2019GL084217 Abstract Seismic signals from ocean‐solid Earth interactions are ubiquitously recorded on our planet....


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tldr; Increased density corresponds with decreased P-wave velocity The P-wave velocity for an isotropic medium is: $$ V_p = \sqrt\frac{K+4/3\mu}{\rho} $$ where $K$ is the Bulk Modulus, $\mu$ is the shear modulus, and $\rho$ is the density (https://en.wikipedia.org/wiki/Elastic_modulus, see $M$ the P-wave modulus). Isotropy just means that the strain on ...


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You can retrieve that information from ERA5 reanalisys data. It cover the whole world from 1979 until almost the present. The resolution is 0.25°x0.25° and includes many fields that characterize ocean waves. here is a list of available fields for download in the "Ocean Waves" section: And there is of course, winds data as well.


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I don't know if I fully grasp your question; but I can confirm that slowness and velocity vectors are kind of weird things :-) Let me describe a simple example (and not worry too much about the mathematical details). If in the figure above, if you point your wave not diagonally but just straight down, what happens? Well, $dx$ becomes infinitely large when ...


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I have no experience with SBP-SAT methods, but you may try and go through the references in (and potentially contact the authors of) this paper https://arxiv.org/pdf/1802.06123.pdf . Personally, I don't see a strict need for using such 'complicated' modelling methods for RTM. In the ideal case, you have deghosted (i.e., upgoing) recorded data and a smooth ...


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This is conceptually relatively simple if you look at where the reflection (and refraction) happen, and in fact you have articulated the key concept in your question: The reflected wave ...Over time it becomes more horizontal and therefore more like a direct wave which takes a shorter and quicker path across the surface. This is absolutely correct. So ...


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So, I know this question was asked a long time ago. But in the spirit of Stack Exchange, I will post my answer for future users perhaps. The Greens functions (i.e., analytical solutions) The first thing to be aware of are the various solutions to the wave equations change for the (1) source type and (2) the dimension. The source type Assuming acoustic ...


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There are two ways in which waves can sort particles on a beach, and both depend on surface area to weight ratio. The larger, toe-sized particles you describe have less surface area to volume (weight) ratio than the sand-sized particles, so were first to drop out of the water flow. The lighter particles had more surface area per unit of weight for the waves ...


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