Sismicidade e esforços tectônicos na zona sísmica Acaraú, Nordeste do Brasil

Inside the Borborema Province the Northwestern Ceará (NC) is one of the most seismic active regions. There are reports of an earthquake occurred in 1810 in the Granja town. On January, 2008 the seismic activity in NC has increased and it was deployed a seismographic network with 11 digital stations. In 2009, another earthquake sequence began and it was deployed another seismographic network in the Santana do Acaraú town with 6 stations. This thesis presents the results obtained by analyzing the data recorded in these two networks. The epicentral areas are located near the northeastern part of the Transbrasiliano Lineament, a shear zone with NE-SW-trending that cuts the study area. The hypocenters are located between 1km and 8km. The strike-slip focal mechanisms were found, which is predominant in the Borborema Province. An integration of seismological, geological and geophysical data was performed and it show that the seismogenic faults found are oriented in the same direction to the local brittle structures observed in field and magnetic lineaments. The SHmax (maximum compressional stress) direction in NC was estimated using an inversion of seven focal mechanisms. The horizontal maximum compression stress (σ1 = 300°) with orientation NW-SE and extension (σ3 = 210°) with NE-SW and σ2 vertical. These results are consistent with results of previous studies. The seismic activity recorded in NC is not related to a possible reactivation of the Transbrasiliano Lineament, by now.

Estudo da sismicidade na barragem do Açu no período de 2012 a 2013

The seismic activity in the Northeastern of Brazil has been a constant target of study, since it is the most active region of the country. However, some areas have their earthquakes related to human action, what means they are induced. The Açu dam is a classic example of reservoir-induced seismicity and it has been the subject of several studies. Recently, after a considerable period of inactivity, the LabSis / UFRN recorded events related to the dam, which led to the installation of a network around the reservoir. From the data provided by this network, it was observed that the seismic activity is related to a new epicental area inside the lake. The epicentral parameters and the focal mechanism were determined. It was found that the events were related to the reactivation of a basement structure in a new seismogenic subvertical fault with NE-SW-striking subparallel to the São Rafael Fault. These results were used in the preparation of a scientific paper, which discussed the relationship between this seismicity with the geology of the region and with the reservoir water level. The paper showed that the diffusion of pore pressure was the main mechanism that controlled the triggering of the induced seismicity at the reservoir.

Estudo da sismicidade na barragem do Açu no período de 2012 a 2013

The seismic activity in the Northeastern of Brazil has been a constant target of study, since it is the most active region of the country. However, some areas have their earthquakes related to human action, what means they are induced. The Açu dam is a classic example of reservoir-induced seismicity and it has been the subject of several studies. Recently, after a considerable period of inactivity, the LabSis / UFRN recorded events related to the dam, which led to the installation of a network around the reservoir. From the data provided by this network, it was observed that the seismic activity is related to a new epicental area inside the lake. The epicentral parameters and the focal mechanism were determined. It was found that the events were related to the reactivation of a basement structure in a new seismogenic subvertical fault with NE-SW-striking subparallel to the São Rafael Fault. These results were used in the preparation of a scientific paper, which discussed the relationship between this seismicity with the geology of the region and with the reservoir water level. The paper showed that the diffusion of pore pressure was the main mechanism that controlled the triggering of the induced seismicity at the reservoir.

Evolução morfotectônica da porção centro-sul da Bacia Paraíba

Recent endogenous processes provide dynamic movements in the lithosphere and generate the varied forms of relief, even in areas of passive continental margins, such as the research area of this work located in northeastern Brazil. The reactivation of Precambrian basement structures, after the breakup between South America and Africa in the Cretaceous played an important role in the evolution of basins, which provided generated forms of relief. These morphodynamic characteristics can be easily observed in marginal basins that exhibit strong evidence fault reactivations. The purpose of this study is to investigate the influence of morphotectonic processes in the landscape structuring of Paraíba Basin. Therefore, we used aeromagnetic, high–resolution images of the Shuttle Radar Topographic Mission–SRTM, structural geological data, deep well data and geological field data. Based on the results of the data was observed that some preexisting structures in the crystalline basement coincide with magnetic and topographic lineaments interpreted as fault reactivation of the Post–Miocene units in the Paraíba Basin. Faults that offset lithostratigraphic units provided evidence that tectonic activity associated with the deposition and erosion in the Paraíba Basin occurred from Cretaceous to the Quaternary. The neotectonic activity that occurred in Paraíba Basin was able to influence the deposition of sedimentary units and landforms. It indicates that the deposition of post–Cretaceous units was influenced by reactivation of Precambrian basement structures in this part of the Brazilian continental margin.

Laços Sociais e Capital Social nas Narrativas das Pessoas em Situação de Sem-abrigo

A pertinência da rutura e reconstrução dos laços sociais nas pessoas em situação de sem-abrigo leva-nos à abordagem dos seus processos idiossincráticos de emergência e manutenção do capital social nos laços sociais. A investigação pretende, através dos discursos de pessoas que experienciam a situação de sem-abrigo, compreender como emerge e se mantém o capital social nos laços sociais. Assim, utilizou-se a entrevista semiestruturada para aceder às suas narrativas. A escolha dos participantes teve em consideração a acessibilidade e disponibilidade dos indivíduos na cidade de Coimbra. Das narrativas dos seis entrevistados verificou-se que apresentam um capital social vulnerável associado a uma escassa rede de apoio (formal e/ou informal). Emergiu dos seus discursos que um dos principais fatores que concorre para a emergência da situação de sem-abrigo é a rutura com os diferentes tipos de laços sociais, sobretudo os familiares, que potencia a diminuição da rede de suporte, e tem repercussões nas diferentes dimensões do capital social, dificultando a sua emergência. A rutura dos laços de filiação e parentescos foram identificados pelos entrevistados como o principal fator para a emergência da situação de sem-abrigo, evidenciando também uma quebra dos níveis de confiança para a possível criação de novos laços ou reativação/reconstrução dos laços quebrados. As conclusões da presente investigação constituem um contributo para o Serviço Social, na medida em que um conhecimento mais aprofundado da situação de sem-abrigo, pelas suas próprias vozes, assim como dos seus laços sociais e das suas ruturas, e das dificuldades sentidas na emergência e manutenção do capital social, permitirão a concertação de estratégias de intervenção mais ajustadas à realidade com estas pessoas e com este problema social.

NOVOS INVESTIMENTOS DA PETROBRAS E SUAS IMPLICAÇÕES SOCIOESPACIAIS NOS MUNICÍPIOS DE MARAGOGIPE E NAZARÉ, BAHIA - BRASIL

A contemporaneidade exige constantes reformulações das práticas econômicas, e nisto o território, base material das ações humanas, também é constantemente reestruturado para atender as demandas sociais advindas de novos fluxos e fixos. O presente trabalho visa identificar e compreender as dinâmicas territoriais advindas dos processos de reativação do estaleiro de São Roque do Paraguaçu, pertencente à Petrobras, para os municípios de Maragogipe e Nazaré, no Estado da Bahia, Brasil. A realização deste estudo exige a pesquisa bibliográfica, como também a coleta de dados em campo, incluindo registro fotográfico e levantamento estatístico e documental em empresas e instituições. Serão analisados documentos como o PAC – BA (Plano de Aceleração do Crescimento), Plano de Desenvolvimento Regional Sustentável e Plano Plurianual, além de aplicadas entrevistas. Essa obra promove nos municípios supracitados e circunvizinhos certa dinamização, já que movimenta o comércio, as redes de hospedagem e alimentação, gera empregos e a demanda de cursos técnicos e profissionalizantes, podendo contribuir para o desenvolvimento local.