SH plane-wave reflection/transmission coefficients in isotropic, attenuating media

0548480 - GFÚ 2023 RIV NL eng J - Journal Article
Pšenčík, Ivan - Wcislo, Milosz - Daley, P. F.
SH plane-wave reflection/transmission coefficients in isotropic, attenuating media.
Journal of Seismology. Roč. 26, č. 1 (2022), s. 15-34. ISSN 1383-4649. E-ISSN 1573-157X
R&D Projects: GA MŠMT(CZ) LM2015079
Institutional support: RVO:67985530 ; RVO:67985891
Keywords : attenuation * weak-attenuation concept * correspondence principle * SH-wave displacement * reflection/transmission coefficients
OECD category: Volcanology; Volcanology (USMH-B)
Impact factor: 1.6, year: 2022
Method of publishing: Limited access
https://link.springer.com/article/10.1007/s10950-021-10052-x

An attempt is made to extend the applicability of the weak-attenuation concept (WAC) to ray-theory computations. WAC allows an approximate evaluation of effects of attenuation on seismic-wave propagation in smoothly varying laterally inhomogeneous media encountered in most seismological studies. The goal is to find under which conditions WAC could be applicable to layered media. Specifically, if the use of WAC is necessary, under which conditions it can be used for the approximate evaluation of the reflection and transmission coefficients at interfaces separating attenuating media. It turns out that outside critical incidence regions, where the ray theory is not applicable, the effects of attenuation on the reflection and transmission are negligible in comparison with effects of attenuation on wave propagation inside layers. Despite it, the approximate formulae for reflection and transmission coefficients including effects of attenuation are derived and presented. For better insight and simplicity, effects of attenuation on SH plane-wave coefficients at interfaces separating homogeneous, attenuating isotropic half-spaces are studied. The coefficients are expressed in the form of the sum of coefficients in a reference elastic medium plus a perturbation due to weak attenuation. The study is based on the assumption of the validity of the correspondence principle despite indications of its inapplicability in some situations. A fixed frequency is considered. A basic role in the evaluation of coefficients is played by slowness vectors of incident and transmitted waves. They are required to satisfy constraints resulting from the corresponding equation of motion, Snell's law and radiation condition. The resulting formulae for coefficients are singular for the angles corresponding to critical incidence in the reference elastic medium.
Permanent Link: http://hdl.handle.net/11104/0324497