Abstract
The construction of earthen embankment terraces in the Douro Region raises a set of problems related to hydrological processes. The main objective of this study is the evaluation of the spatial variation of electrical resistivity in agriculture terraces at Douro valley (Portugal). To achieve this objective, two variables are analysed, the soil electrical resistivity and the flow direction algorithm. In a field survey we recorded 13 electrical resistivity profiles. The contributing area was calculated with the algorithms D infinity (Deterministic Infinity Flow) and MFD (Multiple Flow Direction) and the results are the base of the internal runoff modelling, both supported by the digital elevation model with a spatial resolution of 1m2. A correlation between the spatial variation of the soil electrical resistivity represented by the standard deviation of the electrical resistivity for each profile and the average value of the contributing area coincident with each profile was established. The electrical resistivity standard deviation seems to be moderately well correlated according to the D infinity algorithm at about 1m of depth, and it has a good correlation at 1,5m to 2m of depth with the MFD algorithm. Taken together, the results show a significant positive statistical correlation between the electrical resistivity standard deviation and the contributing areas (MFD and D infinity) depending on the soil depth.

Abstract
Located in the northern part of continental Portugal, the city of Porto is characterized by low-to-moderate levels of seismicity, thus one of reasons for the lack of studies regarding the influence of site effects in this area. In this study, the HVSR technique (horizontal-to-vertical spectral ratio) was used in order to obtain information about the fundamental frequencies of the ground in several parts of the city which was later compared to the geotechnical information presented in the Geotechnical Map of Porto, with the aim of establishing a possible correlation between frequency values and sub-soil geotechnical characteristics. This type of research plays an important role in understanding how local geological characteristics may influence the amplification of seismic waves. For this purpose, two types of studies were conducted in the city of Porto – two linear test campaigns along two major streets in the city, Boavista Avenue and Constituição Street; and one dispersed test campaign within the hydrographic basin of Frio River, an underground river flowing in the areas of Carregal Garden, Santo António Hospital, Cordoaria Garden and Virtudes Garden. The three campaigns represented a total of 53 recordings of ambient ground noise using a broad band seismometer and the resulted data was used to produce HVSR graphics. From these graphics it was possible to determine the fundamental frequencies (f0) of several points within the city. Resorting to the geotechnical map of the city and having identified the geotechnical units existing in each test place as well as the parameters used to their classification, it was possible to establish a connection between frequency values and substrate competence. The results suggest a strong relation between these parameters, low frequencies relate to softer grounds and as an opposite high frequencies to harder bedrock.

Abstract
The present work shows some results obtained by the Time-Domain Electromagnetic Method (TDEM) to help characterize the geology and Penacova- Régua-Verin fault structure in the Vila Pouca de Aguiar sector. The Fault is an important tardi-variscan structure with NNE-SSW direction, more than 500 km long, extending from the North of Spain until near Nazaré. The application of the TDEM method aimed to acquire data towards obtaining profiles of subsurface electrical resistivity in the zone affected by the fault and adjacent terrain. Electrical resistivity profiles, resulting from the combination of individual soundings, were performed in the SW quadrant of 6D-Vila Pouca de Aguiar of Carta Geológica de Portugal sheet, at a scale of 1/50 000, along Penacova-Régua-Verin Fault and perpendicularly, with WNW-ESE orientation, in the western sector of the fault. Some confirmation and preliminary models were accomplished using the results obtained by other authors, allowing to verify the validity of the obtained inverted data. The method responded in accordance with the conceptual model but allowed the additional distinction between alteration zones and apparently identical lithologies. Overall, three main blocks were identified, the most superficial shows high resistivities and low thickness. The second block has lower resistivity values due to the influence of the water level at this depth. In the third block, more oscillatory characteristics were identified throughout the various surveys. Although, in general, its high thickness and high values of electrical resistivity were highlighted. However, one of the obstacles in the implementation of the method was the presence of wind farms in Northern Portugal, bridges, metal fences, as well as power lines and high voltage pylons that produce electromagnetic noise and thus interfere with the readings obtained.

Abstract
The geophysical surveys methods have not been extensively used in gold exploration in Northern Portugal. This is based on the fact that most mineralized zones contain low and erratic sulphide contents. In this work we3re tested three different types of geophysical surveys combined with geochemical surveys, in order to define anomalies that are closely correlated with the locations of known mineralized zones. The aim of the work is to study some gold deposits in Northern Portugal (Lagoa Negra and Castromil) with the purpose of obtaining valuable information of the mineralogical and petrogenetically features of these gold deposits, and how it would facilitate the understanding of the regional distribution and formation of gold deposits. Ground Penetrating Radar (GPR), Very Low frequency (VLF) electromagnetic methods combined with 2D Electrical Resistivity techniques can contribute towards defining structures, and are particularly important where extensive cover exists and may also play an important role in the mapping of lithology and the lithological contacts. The magnetic surveys revealed and confirmed two possible areas with sulphide mineralization, one with pyrrhotite and other with Fe-sulphide oxidation proven by during drilling campaign in this area. This work demonstrates how the combination of geophysics and geochemical methods, together with geological sampling, can be used to help delineate possible structures that host gold mineralization.

Abstract
The inclusion of site-specific conditions is essential to adequately represent the seismic hazard and the seismic risk for a region. We acquired, gathered, and organized a near-surface shear-wave velocity database for Portugal and applied a three-step methodological approach for developing a V-S30 site-condition map using extrapolation based on surface geology. The methodology includes (1) defining a preliminary set of geologically defined units, (2) calculating the probability distribution of log V-S30 for each unit, and (3) merging the units according to the results of statistical tests. The final model comprises three geologically defined units characterized by log V-S30 distributions that are statistically significantly different from each other: F1, igneous, metamorphic, and old sedimentary rocks; F2, Neogene and Pleistocene formations; and F3, Holocene formations. The site conditions for the F3 unit may be further refined using correlations with topographic slope based on the Shuttle Radar Topography Mission at 3 arcsec resolution (SRTM3) dataset. We analyzed the performance site-condition models based on correlations with exogenous data (topographic slope and surface-geology analogs). The results show that the residual distributions between log V-S30 values measured and estimated from those proxies are strongly biased for some geological units, emphasizing the need for acquiring regional V-S data.

Abstract
Mental models are students' representations of the real world based on their knowledge and understanding. In a meaningful learning it is essential to analyse students' mental models and promote a reconstruction of scientific knowledge, by allowing them to become consistent with the scientific models. Having this in mind, we aimed to analyse undergraduate students' mental models concerning the seismic effects on soils and buildings, before they learn these contents at the university. To collect the data we applied a questionnaire with several items. The questionnaire was answered by a convenient sample of 31 freshmen from an undergraduate degree in Geology, in a northern Portuguese university. The results show that, in the majority of the items, students recognized the seismic effects on soils and buildings. However, some of their mental models were inconsistent with the scientific model, highlighting the importance of diagnosing students' mental models and their restructuring to promote a meaningful learning and scientific literacy.