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This work presents evidence of seasonal and inter-annual variations of the earthquake occurrence rate in the Azores Triple Junction, on the Mid-Atlantic Ridge (MAR). Annual cycles in microearthquakes are relatively common in intraplate continental regions affected by large hydrological loads, but this is the first time that earthquake seasonality is recognized near mid-ocean ridges. First, we benchmark the methodology by matching the published results of earthquake seasonality in the intraplate New Madrid Seismic Zone (USA). Next, we analyze the Azores earthquake catalogue, from 2008 to 2018, separately for oceanic and island regions. The results demonstrate that the seasonal modulation of the seismicity rate is only observed in the ocean, especially in the vicinity of the triple junction, with more earthquakes occurring during the summer months from May to August. Monte Carlo simulations show that the probability of observing such seasonality by chance is less than 1% for the magnitude band from 3.3 to 4.5, well above the detection threshold and magnitude of completeness of the seismic catalogue. The methodology includes a Jack-Knife approach, which shows that the oceanic seasonality is not the consequence of abnormal or extreme events. Although we speculate about possible earthquake triggering processes, it remains a challenge to definitely establish the mechanism responsible for the observed earthquake seasonal modulation in the Azores. [ABSTRACT FROM AUTHOR]

Fluctuations in groundwater level in the Ria Formosa coastal aquifers, southern Portugal, owe 80% of the variability to climate-induced oscillations. Wavelet coherences computed between hydraulic heads and the North Atlantic Oscillation (NAO) and East Atlantic (EA) atmospheric teleconnections show nonstationary and spatially varying relationships. The NAO is the most important teleconnection and the main driver of long-term variability, inducing cycle periods of 6–10 years. The NAO fingerprint is ubiquitous and it accounts for nearly 50% of the total variance of groundwater levels. The influence of EA emerges coupled to NAO and is mainly associated with oscillations in the 2–4-year band. These cycles contribute to less than 5% of the variance in groundwater levels and are more evident further from the coast, in the northern part of the system near the main recharge area. Inversely, the power of the annual cycle increases towards the shoreline. The weight of the annual cycle (related to direct recharge) is greatest in the Campina de Faro aquifer, where it is responsible for 20–50% of the variance of piezometric levels. There, signals linked to atmospheric teleconnections (related to regional recharge) are low-pass filtered and have periods >8 years. This behavior (lack of power in the 2–8-year band) emphasizes the vulnerability of coastal groundwater levels to multi-year droughts, particularly in the already stressed Quinta do Lago region, where hydraulic heads are persistently below sea level. [ABSTRACT FROM AUTHOR]

Highlights • Climate forcing explains 80% of the piezometric level variability in Portugal. • NAO is the leading pattern (40–60% of explained variability) with 6–10 year cycles. • Higher frequency fluctuations (2.5, 3.3 and 4.2 year periods) are linked to EA and SCAND. • EA is more influent in the north and SCAND in the south of the country. • Coupled NAO and EA phases are associated with extreme piezometric levels. Abstract Under the increasing risk of water scarcity, aquifer management strategies can take advantage of a deeper knowledge about the natural long-term fluctuations driven by climate patterns. This study examines the links between major large-scale atmospheric circulation modes and inter-annual to decadal oscillations in groundwater levels in Portugal. Precipitation and piezometric records (1987–2016) from two aquifer systems, Leirosa-Monte Real in the north and Querença-Silves in the south, are analyzed using wavelet transform methods and singular spectral analysis. Wavelet coherences computed between hydrologic time series and the North Atlantic Oscillation (NAO), East Atlantic (EA) and Scandinavia (SCAND) climate patterns show non-stationary relationships that are nonetheless consistent in distinct period bands. The strongest covariability occurs in the 6–10 years band for NAO, in the 2–4 years band for EA (especially after 1999) and in the 4–6 years band for SCAND (mainly after 2005). NAO is the mode playing the most relevant role with a stronger influence in the south (60% on average) than in the north (40% on average). The relatively higher frequency (<5 year period) contributions of EA and SCAND are difficult to set apart but their joint impact accounts for approximately 20% and 40% of the total variance of groundwater levels in the south and north of the country, respectively. Wavelet coherence patterns also expose transitive couplings between NAO, EA and SCAND. Often, coupled phases between climate modes mark abrupt transitions in synchronization patterns and shifts in the time-frequency domain. Extremes in groundwater storage coincide with anti-phase NAO and EA combinations: maximum piezometric levels occur during NAO-EA+ (coincidentally also SCAND+) phases while minimum levels occur during NAO+EA− phases. [ABSTRACT FROM AUTHOR]

This study examines the role of gravitational potential energy (GPE) in generating second-order (spatial scale ∼10 2 km) variations in the Iberia stress and strain-rate patterns. We present a new map of present-day strain rate field derived from the secular velocity field computed using all available continuously operating Global Navigation Satellite Systems (GNSS) stations in Iberia. The estimated strain rate field is generally consistent with the tectonic framework of the Iberian region, even though sporadic sharp local variations downgrade its correlation with the regional stress patterns. Many of the sharp spatial variations in the strain rate map are consistent with local changes of deformation style determined by prevailing faults. To obtain a more accurate estimate of GPE we use new data on the structure of the crust and apply a thin sheet approach using a 3-D definition of deviatoric stress. The GPE is derived from two isostatically compensated models (GPEd and GPEe compensated by density and elevation adjustment, respectively) and from the truncated geoid (GPEg). The GPE stresses are then summed with the first-order stress field due to the Eurasia–Nubia (EU–NU) convergence and the results compared with both the stress and strain rate data. In agreement with previous studies, we find that the GPE does not significantly change the NW–SE average direction of the most compressive stress (SHmax) imposed by the EU–NU collision, its main effect being to cause spatially changing stress regimes. From the analysis of the different GPE models we find: (1) in the Pyrenees, the tectonic forces have a secondary role when compared to the GPE. In this region, the model that best correlates with observations is the one emphasizing the role of surface elevation as a source of GPE (GPEe); (2) in the Iberian Chain and the Betics, the GPE imposes NE–SW extension consistent with a strike-slip regime and is equally (GPEe) or more (GPEg) important than the tectonic forces. In these regions, both deep heterogeneities associated with mantle convection and elevation are important sources of GPE; (3) in western Iberia, the GPE differences work against dominant tectonic forces by reducing the SHmax magnitude. The GPEg model is the one that best predicts the average strike-slip regime in Galicia; and finally (4) in the Gulf of Cadiz the gravitational potential stresses have a minor role and the style of deformation is clearly controlled by the tectonic forces. [ABSTRACT FROM AUTHOR]

Abstract: Many aspects of modern research and other professional activities in the geosciences require advanced knowledge about mathematical physics models and scientific computation methods and tools. In-depth meaningful learning of such knowledge skills is a difficult cognitive process which involves developing strong background knowledge of physics, mathematics and scientific computation appropriately contextualised in the geosciences themes. In this paper we describe an interactive engagement teaching approach that is based on Modellus, a freely available computer software system allowing (1) mathematical modelling ranging from explorative to expressive modelling, (2) the introduction of scientific computation without requiring the development of a working knowledge of programming and (3) the simultaneous manipulation and analysis of several different model representations, namely, tables, graphs and animations with interactive objects having properties defined in a visible and modifiable mathematical model. As examples of application, with insights for the development of other activities in a wide range of geosciences courses, we discuss a set of interactive computational modelling activities for introductory meteorology we have implemented in undergraduate university courses. [Copyright &y& Elsevier]

Abstract: In the Gulf of Cadiz the water/sediment load and the density contrasts between the continental and oceanic lithosphere are sources of vertical loading causing flexure. The main objective of this work is to investigate the relation between the bending stresses associated with flexural isostasy and the observed pattern of deformation and seismicity. For that we combine a strength analysis and finite element numerical modelling along a previously studied (Fernandez, M., Marzán, I., Torné, M., 2004. Lithospheric transition from the Variscan Iberian Massif to the Jurassic oceanic crust of the Central Atlantic. Tectonophysics, 386, 97–115) vertical section of the lithosphere, approximately perpendicular to the Africa-Eurasia convergence. We find that the flexural stresses are focussed in the ocean–continent transition, within a zone approximately 150km wide, between the base of the continental slope and the Horseshoe Abyssal Plain. We show that the flexural stresses are mainly supported by the upper mantle and predict their values for two different thermal scenarios. The compositional layering in the crust is shown to play an important role in the focussing of the strain energy along the crust/mantle interface. Finally, we observe that there is a correlation between the modelled strain energy and the earthquake distribution. The maximum compressive stress difference can be as much as 65% of the strength in compression. The maximum influence is observed at 10km depth near the Horseshoe Abyssal Plain. We conclude that flexural stresses alone are not enough to cause rupture or yielding in the Gulf of Cadiz. However, like plate boundary forces and inherited mechanical weaknesses, they need to be incorporated when assessing seismic hazard in this region. [Copyright &y& Elsevier]

Research on climate-driven variability in the water and energy sectors is required to drive adaptative policies to climate change and boost cross-sectorial synergies. This study addresses the role of the North Atlantic Oscillation (NAO) and East Atlantic pattern (EA) on the water-energy nexus in southern Portugal (Algarve region) from the point of view of water demand, instead of the usual point of view of hydropower production. Water at surface reservoirs and aquifers and solar and wind energy potentials (SP and WP, respectively) do not share the same dominant variability scales, but their interrelationships have implications for leveraging the use of renewable energy in the water sector, particularly through water pumping efficiency gains. Water availability is dominated by interannual fluctuations (70% of the total variance), whereas SP and WP are characterized by seasonal variability scales (98% and 41% of the total variance, respectively). At interannual scales NAO is the main driver of low-frequency variability governing cycles in the 6–8 -year band, whereas fluctuations in the 2–4 -year band are mainly associated with EA. Coupling or synchronizations between opposite phases of NAO and EA correspond to extremes in water availability. Minimum water levels in the summer and during droughts, corresponding to maximum energy demand in the water sector, are clearly connected to synchronized positive NAO and negative EA phases in the preceding winter. Recent advances in the seasonal and long-term predictability of NAO and EA climate patterns can help to improve drought resilience and groundwater sustainability and have huge potential benefits for the water-energy nexus in the Algarve region. Finally, to decarbonize freshwater supply in the Algarve, policy instruments will need to account for unregulated pumping which enables conditions for groundwater depletion, encourage energy and water management integration, and explore innovative energy investments. • NAO (and EA) drive interannual variations with peak periods of 6.5 (and 3.5) -years. • Maximum energy demand in the water sector is expected for NAO+ and EA− phases. • SP is the most reliable renewable energy source for the water sector in the Algarve. • NAO+ EA− are associated with droughts raising implications for solar and wind energy. • Policies promoting solar based technologies should account for aquifer depletion. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to determine, in children with congenital glaucoma, the surgical results, the quality of visual perception, the performance in vision-related activities, the level of participation and the child and parental level of stress. The study was designed according to the ICIDH-2/ICF (WHO) and functional vision was evaluated using Colenbrander''s visual ability scales. The functional results of the surgical treatment were measured and the assessment of functional vision pointed to the areas of abilities in need for rehabilitation. After the rehabilitative intervention the impact on the vision-related skills and abilities showed optimisation of visual capacities and greater autonomy. [Copyright &y& Elsevier]