Banca de DEFESA: Gustavo Lopes Costa

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Gustavo Lopes Costa
DATE: 27/03/2024
TIME: 09:00
LOCAL: Instituto de Geociências - IG e "On Line"
TITLE:

Aerogeophysical Characterization of Fractured Crystalline Aquifer System in the Brazilian Northeastern Semiarid: A Contribution to Hydrogeophysical Knowledge in a Drought-Prone Region.

KEY WORDS:

3D modelling; Inversion; airborne electromagnetics; FDEM methods; Brazilian Semiarid Region; Groundwater; Hydrogeology, Hydrogeophysics.

PAGES: 114
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The intense drought occurring in Northeast Brazil exacerbates various existing problems in the region. In this scenario, water scarcity affects everything from the subsistence of the population to socio-economic development, particularly large-scale agriculture. Difficulties in exploiting water resources have led to the need to search for a water capture method, and drilling of groundwater wells has become one of the most commonly used methods in the Brazilian semi-arid region. This study aims to observe the relationship and effectiveness of the application of airborne geophysical data in identifying structures and delimiting regions with high favorability for groundwater Página | xi retention. The data from the PROASNE-Brazil Project, released by the Brazilian Geological Survey (SGB-CPRM), will be utilized for this purpose. The objective of PROASNE is to improve living conditions in the northeastern region of Brazil by providing sustainable solutions to problems caused by seasonal drought. PROASNE involved the acquisition of airborne geophysical data obtained by helicopter (HEM) in the Serrinha-RN region. Magnetometry was sensitive to delineating magnetic contacts and detecting high-angle structures through Euler's solution and Analytic Signal Amplitude. The survey used electromagnetic methods, specifically in the frequency domain (FDEM), which is a potential tool for mapping and distributing underground water resources in crystalline basement environments. Apparent conductivity images were obtained for three nominal frequency bands, distinguishing shallow to deep conductors. Depth-sliced conductivity sections (CDI) were generated for all flight lines to create a 3D Voxel mesh of the apparent conductivity for the entire research area in the Serrinha region. Subsequently, the 3D inversion of the electromagnetic data was performed using Voxi 3D. The CDIs showed elevated conductive values near drilled boreholes registered in the Groundwater Information System (SIAGAS) and geological structures mapped by the SGB. Conductive zones in crystalline terrains were detected, showing a direct relationship between conductivity and the presence of saline water. This research highlights two essential factors: the successful identification of structures and subsurface regions with high potential for water infiltration and storage; the application of processing techniques to airborne electromagnetic data has demonstrated potential in contributing to the advancement of hydrogeological and hydrogeophysical research in the Brazilian semi-arid region, with potential applicability to other areas.

COMMITTEE MEMBERS:
Interno - 2156153 - ELDER YOKOYAMA
Presidente - 1823156 - GIULIANO SANT ANNA MAROTTA
Interno - 1734151 - LUCIANO SOARES DA CUNHA
Externo à Instituição - VAGNER ROBERTO ELIS - USP