Dear Redouane Chimouni,

Surface seismic waves from an earthquake propagate in an anisotropic geological environment, where the attenuation coefficient depends on the consolidation (cohesion) of the earth's crust. Main mistake. Earthquakes with a hypocenter depth in the mantle propagate over greater distances than earthquakes with hypocenters in the earth's crust.

Check out the discussion "Earthquake engineering and the structural seismic resistance". There is my answer "In addition, I attached a video in the city of Moscow (Russia). The reason for the vibrations of buildings is an earthquake in the Sea of ​​Okhotsk at a distance of 9000 km In the epicenter area, the population did The earthquake was at a depth of 500 km, magnitude over 9 (24.05.2013).

I want to congratulate you, you can be the first to explain this process." There is a video there. This is the strongest earthquake on record. You have a network of seismic stations at your disposal. And you can see the degree of anisotropy of the geological environment. In other directions, surface seismic waters almost died out.

Sincerely, Boris.

Thank you Sir for your explanation and for sharing the video.

This is very helpful.

I found today that changing the Qp and Qs parameters in the velocity model can help a little. Don't know for sure how to fix it for now though.

Thank you very much for your help

Dear Redouane Chimouni, You may be interested in information about the patterns of the earth's crust to deform in different azimuths. The earth's crust consists of tectonic blocks that can move in a vertical direction with an amplitude of about 50 cm. The shape of the tectonic blocks is square. Their dimensions are multiples and submultiples of 140x140 km. Of the two adjacent tectonic blocks, one rises and the other descends. On the surface of the earth, a system of blocks forms a rectangular grid of faults.

Important information. Several such networks of faults formed simultaneously on the Earth's surface. These fault networks are formed with azimuths of 0° and 270°; 17° and 287°; 35° and 305°; 45° and 315°; 62° and 332°; 77° and 347°. In the case when the seismic wave is directed along one of these azimuths, its amplitude will be preserved at large distances from the epicenter. An example of deformation of the earth's surface not related to an earthquake can be viewed on a video from the Internet.

Also check out the discussion "How to estimate rock fracturing due to tectonic activity?" and my answer "The wave energy is proportional to the amplitude to the second power. What amplitude of seismic waves do you know. The amplitude of the tides in the solid body of the Earth is ten times greater. This means that the formation of cracks during an earthquake does not matter. Another issue is when the tides in the solid body of the Earth do not have sufficient energy to form deformations in a local area of the earth's crust. You can see the section of our monograph on seismic gaps "Teacher I., Kapochkin B. Paradigm shift in modern geodynamics and seismotectonics, LAP. LAMBERT Academic Publishing, 2014, 80 pp. ISBN-13: 978-3-659-53087-6. Sincerely, Boris." Sincerely, Boris.

Thank you very much for those details.

I will check the monograph you mentioned.

Thank you