Banca de QUALIFICAÇÃO: EDILSON BARAUNA DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : EDILSON BARAUNA DOS SANTOS
DATE: 16/11/2024
TIME: 10:00
LOCAL: Auditório do Departamento de Geofísica - UFRN
TITLE:

Can constant �� models describe the GPR signal attenuation caused by natural dielectrics?

KEY WORDS:

Attenuation; GPR; Jonscher Formalism; Power-law; Permittivity; Constant Q model

PAGES: 38
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geofísica
SUMMARY:

This study investigates the attenuation behavior of Ground Penetrating Radar (GPR) signals in different geological materials, such as deformed and undeformed sandstones and carbonates, using the quality factor �� model from Jonscher's formalism. One of the objectives of this work is to determine whether the constant �� model is suitable for describing the observed attenuation in the studied materials, and the results are compared with the power-law adjustment of the proposed model. The samples were obtained from the Rio do Peixe Basin and the Potiguar Basin, with their properties experimentally analyzed. The methodology included permittivity measurements with the RF material/impedance analyzer Agilent E4991A, and the data obtained were adjusted using a code based on Jonscher's model. The results indicate that the constant �� model does not adequately describe the observed variability in the samples. In contrast, the power-law offers a better fit, effectively capturing the fluctuations of the �� factor as a function of frequency, especially for geologically complex materials such as carbonates and deformed sandstones. The study also shows that the power-law model is a robust tool for modeling attenuation across a range of frequencies, highlighting the need to revisit the use of the constant �� model in contexts where attenuation is strongly influenced by structural heterogeneities. The information obtained from this study is highly relevant to geophysical

investigations, providing important insights for improving GPR data interpretation, particularly in subsurface studies in karstic and fractured environments, where the presence of cavities and dissolution zones directly affects wave propagation.

COMMITTEE MEMBERS:
Externo ao Programa - 2411277 - MANILO SOARES MARQUES - nullPresidente - 1506706 - MILTON MORAIS XAVIER JUNIOR
Interno - 1298588 - RENATO RAMOS DA SILVA DANTAS