Izabela Kudela | Searcharxiv

arXiv2020

On possible issues of Backus average

In this paper, we continue the study of Bos et al. (2018) regarding statistical and numerical considerations of the Backus (1962) product approximation. While the approximation is typically quite good for seismological scenarios, Bos et al. (2018) demonstrate a physical scenario that could, in spite of the stability conditions for isotropic media, lead to an issue within the Backus average. Using the Preliminary Reference Earth Model of Dziewoński and Anderson (1981) and a case study in the upper oceanic crust, we investigate whether this issue is likely to occur in the context of seismology.

physics.geo-ph↗

arXiv2019

On constraints imposed on a transversely isotropic elasticity tensor

We discuss several physical constraints imposed on elasticity parameters of a transversely isotropic (TI) tensor. There are three types of restrictions we investigate; a fundamental one of stability conditions, and two additional ones, commonly considered in seismology. The first commonly considered restriction comes from an assumption of a wave with a greater speed in the horizontal than vertical direction. The second constitute the assumption that quasi-P wave is faster than quasi-S waves. We show several numerical examples to examine how these restrictions affect a TI tensor with known values of certain elasticity constants that could be acquired from the vertical or horizontal measurements.

physics.geo-ph↗