Banca de DEFESA: THAYANE SAMARA DA CUNHA VICTOR
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : THAYANE SAMARA DA CUNHA VICTOR
DATA : 30/08/2019
HORA: 14:30
LOCAL: Auditório do DGEF
TÍTULO:
Joint inversion of high-frequency receiver functions and dispersion curves in the Parnaíba Basin
PALAVRAS-CHAVES:
Joint inversion; Receiver function; Dispersion curve; Sedimentary structure; Parnaíba Basin
PÁGINAS: 120
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:
We assess the performance of the joint inversion of receiver functions (RF) and surface wave dispersion in the characterization of the sedimentary package making the Parnaíba Basin of NE Brazil. This procedure is routinely utilized in passive-source crustal studies to retrieve S-velocity variations with depth under recording stations, and has seldom been used with high-frequency datasets to investigate fine sedimentary structure. The Parnaíba Basin is a Paleozoic cratonic basin composed of up to 5 supersequencies, accumulating up to 3.5 km of sediments interbedded by Late Cretaceous diabase sills. The dataset used for this research was acquired between 2015 and 2017 through deployment of 10 short-period and 1 broadband seismic stations distributed along an approximately 100 km-long linear array in the center of the basin. The deployment was carried out under the Parnaíba Basin Analysis Project (PBAP), a multi-institutional and multidisciplinary effort funded by BP Energy do Brasil. High-frequency RFs (f < 4.8 Hz) were calculated from deconvolution of teleseismic P-waveforms (30o < Δ < 90o) after rotation into the great-circle path (ZRT system), while high-frequency dispersion curves (0.25 - 2 Hz) were obtained through Multiple Filter Analysis of Empirical Green’s Functions (EGFs) developed from cross-correlation (ZZ component) and stacking (6 months) of time-frequency-normalized ambient seismic noise recordings. S-wave velocity-depth profiles down to ~5 km depth were developed through an iterative, linearized joint inversion approach that minimizes the root-mean-square misfit between observations and predictions. Comparison to independent seismic reflection profiles overlapping with our passive-source seismic line reveals the inverted velocity models successfully retrieve thickness of the sedimentary package and depth to the Cenozoic sedimentary sequence. Additionally, high-velocity zones at depths ranging from 1.5 to 2.5 km are observed in the inverted velocity-depth profiles, which are interpreted as due to the Late Cretaceous sills interbedding the basin’s sediments.
MEMBROS DA BANCA:
Interno - 1315614 - DAVID LOPES DE CASTRO
Presidente - 1863578 - JORDI JULIA CASAS
Externo à Instituição - MARCELO BELENTANI DE BIANCHI - USP