Banca de QUALIFICAÇÃO: VICTORIA MARIA DE ALMEIDA SANTOS CEDRAZ

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : VICTORIA MARIA DE ALMEIDA SANTOS CEDRAZ
DATA : 14/02/2019
HORA: 10:00
LOCAL: Laboratório Sismológico - (LabSis/UFRN)
TÍTULO:

Joint inversion of receiver functions and surface-wave dispersion in the Pantanal basin

PALAVRAS-CHAVES:

Passive-source seismology; sedimentary architecture; receiver function

PÁGINAS: 23
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Detailed information on the crustal structure below the Pantanal basin is still scarce. The study of the mechanisms of formation and evolution of this basin and their relationship with the adjacent foreland basins may help understand the effects of the flexure of the South American plate in response to lithospheric loads. In this work, receiver functions and Rayleigh dispersion curves were used to investigate the crustal structure below the Pantanal Basin. The study consisted of: (1) computation of receiver functions for 46 seismic stations in and around the Pantanal basin, belonging to both permanent (BL and BR) and temporary (XC) networks; (2) analysis of P-to-S conversions at the Moho, in order to determine crustal thicknesses and bulk Vp/Vs ratio using the H-κ stacking technique; and (3) joint inversion of receiver functions and dispersion curves obtained from independent tomographic studies, in order to construct 1-D S velocity models for the crust. The results showed average Moho depths of 36.1±1.8 km and average Vp/Vs ratios of 1.69±0.06 in the Pantanal basin, lower than those found in the adjacent areas. The S-wave velocity models confirmed the thinner crust in the Pantanal region. However crustal thickness values from the 1-D velocity models tended to display larger values. As the crust-mantle boundary is actually a zone with finite depth-extent and a velocity gradient, it is believed that the H-κ stacking is selecting the center of the gradient. Existing geodynamic models suggest that the Pantanal Basin formed at the top of a flexural bulge induced by the weight of the Andes on the western edge of the South American plate, causing extensional stresses in the upper crust of the bulge that reactivated pre-existing faults. Our results suggest that crustal thinning processes, perhaps pre-dating the passage of the bulge, influenced the formation of the basin

MEMBROS DA BANCA:
Interno - 1451214 - ADERSON FARIAS DO NASCIMENTO
Presidente - 1863578 - JORDI JULIA CASAS
Externo ao Programa - 346468 - JOSE ANTONIO DE MORAIS MOREIRA