Departamento de Geologia Aplicada

O presente trabalho tem como objetivo explanar a carta de sensibilidade ambiental ao derramamento de óleo (Carta SAO) por meio de uma revisão de literatura. Normatizada a partir da década de 1970, a Carta SAO constitui elemento norteador ao planejamento de ações de contingência em episódios de derramamento de óleo. São abordados a sua gênese, as perspectivas atuais, a situação do cenário brasileiro, culminando com uma rápida abordagem do principal ferramental utilizado na elaboração das Cartas SAO. Há uma ênfase nos modelos baseados no sistema de Índice de Sensibilidade Ambiental (ISA) da National Oceanic and Atmospheric Administration (NOAA), por ser este o mais adotado no Brasil e no mundo. Há destaque às Cartas SAO produzidas aos ambientes marinho e costeiro, reflexo do histórico de aplicação. A oportunidade de evolução metodológica está no desenvolvimento de propostas ao mapeamento da sensibilidade ao óleo dos ambientes terrestres, uma vez que estes são desprovidos de um sistema mundialmente aceito.

This study aimed to provide an alternative approach for the use of a situational diagnosis to evaluate the environmental management systems of the main Brazilian ports. Through this diagnosis, both the enabling factors and barriers to the implementation of an effective environmental management system were identified. The study design was based on Self-Diagnosis Method (SDM) developed by EcoPorts, with the application of a survey on issues involving the various aspects of environmental management scenarios. The responses to the surveys were analyzed using the SWOT matrix in order to identify the strengths, opportunities, weaknesses and threats to the environmental management of the ports under study. Then, gap analysis was performed in order to determine the actions that should be taken for management to evolve from an unsatisfactory status to a desired status. Analysis of the questionnaires revealed a tendency of respondents to minimize the negative aspects of environmental management, and to emphasize the positive aspects. There was also an inconsistency between the responses to the questionnaire and the actions that have actually been taken by the port authorities. This disparity suggests that managers are not willing to confront their problems publicly. The results demonstrated that there is a need for an adoption of the conceptual pillars of Environmental Management in the management of Brazilian ports, as well as for the awareness among all stakeholders involved in the activities, from workers to senior management.

Due to a pipeline rupture on May 15th 1994, 2700 m 3 of a crude oil reached the sea, affecting rocky shore communities, which have been monitored since 1993. These biological data, analysed by BACI approach, were integrated to chemical and toxicological analysis of the oil. Results of Student's t-test did not indicate a significant difference between the percent cover average of the monitored populations (mussels and barnacles) from samples taken before and after the oil spill. The acute and chronic toxicity tests showed high toxicity of the oil. The lack of stress (i.e. mortality) on the populations can be mainly associated to: the sampling area was not highly contaminated despite the great amount of oil which reached surrounding areas; there were not enough physical (smothering) or chemical (toxicity) effects of the oil to alter the density of the populations which are considered moderately resistant to oil.

A faixa litorânea da Ilha de São Sebastião (Ilhabela) que bordeja o Canal de São Sebastião -onde está estabelecido o maior terminal petrolífero do Brasil e ocorre intensa movimentação de petroleiros -constitui o segmento mais impactado por episódios de vazamento de petróleo do litoral norte do Estado de São Paulo. Neste estudo, o segmento centro-oeste deste litoral, com relevância ecológica e significativa importância sócio-econômica, foi mapeado quanto à sua sensibilidade ao óleo na escala 1:10.000. Estudos de campo e laboratório, somados às informações da literatura, permitiram a definição do índice de sensibilidade litorânea para os diferentes padrões da zona entre-marés, que incluem praias arenosas, costas rochosas e manguezal. O histórico de acidentes envolvendo vazamentos de óleo nos últimos 30 anos indica as praias arenosas do norte da parte ocidental da ilha como sendo o segmento mais suscetível a eventos de poluição por óleo. Os resultados obtidos neste trabalho, que também apresenta considerações sobre todo o litoral do arquipélago de Ilhabela, são úteis para planos de contingência e emergência, bem como para o gerenciamento costeiro. Palavras-chave: cartas SAO, litoral norte de São Paulo, petróleo, meio ambiente.

A ocorrência de escorregamentos translacionais rasos no litoral paulista é parte integrante da evolução natural das encostas, que se intensifica sob condições de clima tropical em uma morfologia de serras com desníveis em torno de 700m. Sob precipitações intensas, mesmo sem a interferência direta do homem, os movimentos de massa ocorrem de forma isolada ou generalizada. Devido à presença de um grande histórico de movimentos de massa, tomou-se como área de estudo parte da Serra do Mar Paulista localizada no município de Cubatão-SP. Esse trabalho teve como objetivo avaliar a técnica de análise multicriterial ponderada em SIG -Sistema de Informação Geográfica para elaboração de mapas de suscetibilidades aos escorregamentos translacionais. Buscou-se investigar como a qualidade dos dados e os pesos a eles atribuídos influenciam os resultados. Foram elaborados mapas de suscetibilidade, com diferentes pesos para os diferentes fatores, que são os condicionantes do processo: declividade, forma de vertente e litologias. Da mesma forma, foram também testados mapas de vertente com diferentes formas de obtenção. A utilização de dados de formas de vertente mais detalhados, produzidos a partir do modelo digital de elevação (MDE), produziram mapas de suscetibilidade aos escorregamentos mais adequados para estudos pontuais. Os mapas produzidos com os pesos 70% para declividade, 20% para forma de vertente e 10% para a geologia, no processo de validação, apresentaram o maior número de cicatrizes onde era esperado, na classe de muito alta suscetibilidade.

The continental margin and shelf of most stable intraplate regions tend to be relatively more seismically active than the continental interior. In the southeast continental margin of Brazil, a seismic zone extends from Rio Grande do Sul to Espírito Santo, with seismic activity occurring mainly along the continental slope and suggesting a close relationship with flexural stresses caused by the weight of the sediments. In this region, earthquakes with magnitudes larger than 5 m b occur every 20-25 yr, on average. The focal mechanism solutions of previous earthquakes in this zone indicated reverse faulting on planes dipping approximately 45 • with horizontal P-axes. The recent 5.2 m b earthquake of 2008 April 23 occurred 125 km south of São Vicente and was well recorded by many stations in SE Brazil, as well as at teleseismic distances in North America and Africa. Its focal depth was 17 km, locating the hypocentre in the lower crust. A well-determined focal mechanism solution shows one vertical nodal plane and one subhorizontal nodal plane. The P-and T-axes exhibit large dips, which were confirmed by a regional moment tensor inversion. This unusual orientation of the fault mechanism can be attributed to a rotation of the principal stress directions in the lower crust caused by flexural effects due to the load of recent sedimentation.

This paper presents the results of the application of the Ground Penetrating Radar (GPR) method, or Georadar, in outlining a zone of contamination due to solid residues at the waste burial site of Rio Claro in the state of São Paulo, SE Brazil. A total of eight GPR profiles with 50-and 100-MHz antennae were surveyed. Six profiles were located within the landfill site and the remaining two were outside. The main objective of the GPR survey was to evaluate the side extension of contamination. A Vertical Electric Sounding (VES) survey was performed at four points within the site in order to investigate the vertical extent of the contamination plume and to define the bottom of the landfill. Two additional VESs were done outside the landfill with the purpose of determining the top of the ground water table and the geoelectric stratigraphy of the background. From the interpretation of the GPR profiles, it was possible to locate the top of the contamination plume and to infer that it was migrating laterally beyond the limits of the waste disposal site. This was observed along the profile situated close to the highway SP-127, which was about 20 m from the limit of the site. The signature of the contaminant appears as a discontinuous reflector that is believed to be a shallow ground water table. The discontinuity is marked by a shadow zone, which is characteristic of conductive contaminant residues. The contamination did not move far enough to reach a sugar cane plantation located at approximately 100 m from the border of the site. In the regions free from contamination, the ground water table was mapped at approximately 10 m of depth, and it was characterized by a strong and continuous reflector. The radar signal penetrated deep enough and enabled the identification of a second reflector at approximately 14 m deep, interpreted as the contact between the Rio Claro and the Corumbataí formations. The contact is marked by the presence of gravel characterized by ferruginous concretes, which cause the strong amplitude reflection in the GPR profile. Within the landfill site, the quantitative interpretation of the VES results showed the contamination zone. The base of the landfill varies between 11 and 15 m deep. Outside the landfill site, the VES results showed no indication of contamination and allowed the determination of the top of the ground water table and the contact between the Rio Claro and the Corumbataí formations. The results of GPR and VES showed a good agreement and the integrated interpretations were supported by local geology and information from several boreholes, about 17 m depth, on average. The bottom of the landfill reaches a maximum of 14.5 m depth. D

This paper presents an analysis of receiver functions to estimate crustal structure beneath the Rio Claro Seismological Station, which has been in operation since October 2002. The depths obtained for the Moho discontinuity range from 36 to 44 km. A systematic variation of Moho depths with azimuth was observed. Larger values were obtained with events arriving from the North and the values of 36 km were observed with teleseisms arriving from the SW. This result shows that in the region there is an elevation of the Moho discontinuity near the Domo de Pitanga structural high. This result probably indicates a tectonic origin for this structure caused by deep deformation processes involving the whole lithosphere. RESUMO. Este trabalho apresenta a interpretação da função do receptor determinada para os eventos registrados na Estação Sismológica de Rio Claro, em operação desde outubro de 2002. As profundidades calculadas para a Moho variaram de 36 a 44 km. A análise da variação dos valores de profundidade mostra que eles estão associados aos azimutes dos eventos. Portanto decidiu-se fazer uma análise azimutal dos resultados obtidos. Os maiores valores foram calculados para eventos que se localizamà norte da estação e os valores de 36 km foram calculados para telessismos do quadrante SW. Estes resultados mostram que existe uma elevação da Moho na direção da estrutura "Domo de Pitanga". Estes resultados indicam que esta estruturaé provavelmente de origem tectônica e causada por eventos profundos do manto superior.

Este trabalho mostra os resultados obtidos com a realização de ensaios geofísicos na em áreas de lavra de areia, no município de Descalvado, SP. O objetivo dos ensaios é o de detectar cavidades no interior de arenitos, pertencentes às Formações Pirambóia e Botucatu. Estas cavidades formaram-se com o rebaixamento do lençol freático, necessário para as operações de extração da areia. As técnicas geofísicas utilizadas foram: gravimetria, eletrorresistividade (caminhamento elétrico dipolo-dipolo) e radar de penetração no solo (GPR). Na primeira etapa dos trabalhos foram utilizados a gravimetria e a eletrorresistividade em uma bancada onde ocorreu um desmoronamento devido ao abatimento do teto de uma cavidade. Os resultados obtidos com estas duas técnicas foram coerentes pois a gravimetria mostrou baixos gravimétricos indicando uma "ausência de massa" na área de influência da cavidade e o caminhamento detectou um esperado aumento de resistividade elétrica nesta mesma área. Na segunda etapa, com a realização dos ensaios de GPR em uma bancada próxima à anterior, foi possível detectar cavidades por meio das feições hiperbólicas detectadas nos radargramas.

In order to evaluate the use of shallow seismic technique to delineate geological and geotechnical features up to 40 meters depth in noisy urban areas covered with asphalt pavement, five survey lines were conducted in the metropolitan area of São Paulo City. The data were acquired using a 24-bit, 24-channel seismograph, 30 and 100 Hz geophones and a sledgehammer-plate system as seismic source. Seismic reflection data were recorded using a CMP (common mid point) acquisition method. The processing routine consisted of: prestack band-pass filtering (90-250 Hz); automatic gain control (AGC); muting (digital zeroin) of dead/noisy traces, ground roll, air-wave and refractedwave; CMP sorting; velocity analyses; normal move-out corrections; residual static corrections; f-k filtering; CMP stacking. The near surface is geologically characterized by unconsolidated "fill" materials and Quaternary sediments with organic material overlying Tertiary sediments with the water table 2 to 5 m below the surface. The basement is composed of granite and gneiss. Reflections were observed from 40 milliseconds to 65 ms two-way traveltime and were related to the silt clay layer and fine sand layer contact of the Tertiary sediments and to the weathered basement. The CMP seismic-reflection technique has been shown to be useful for mapping the sedimentary layers and the bedrock of the São Paulo sedimentary basin for the purposes of shallow investigations related to engineering problems. In spite of the strong cultural noise observed in these urban areas and problems with planting geophones we verified that, with the proper equipment, field parameters and particularly great care in data collection and processing, we can overcome the adverse field conditions and to image reflections from layers as shallow as 20 meters.

This paper presents a case study where geophysics was successfully applied to solve a complex problem associated with a tunnel excavation accident in an urban area. It presents and describes the results obtained with geoelectrical methods applied in an emergencial task in a risky urban area in São Paulo City. It also compares the techniques and field arrays, ways to present and interpret the data. The employed methods were electroresistivity, induced polarization (IP) and self potential (SP). The objective of the survey was to delineate the extension of a roof failure of an urban tunnel under excavation beneath the Ibirapuera Park in order to orientate the volume of tunnel roof should be treated. Only two days (Saturday and Sunday) were available to carry out the survey and its interpretation. The results were considered satisfactory and brought a significant economy to the final cost of the tunnel. This economy was due to the decreasing of the remediation area from the initial 20 x...