Isoseismal map of the 1755 Lisbon earthquake obtained from Spanish data

The Royal Academy of History (RAH) of Spain collected very detailed information about the effects on the Spanish territory of the Lisbon, 1755 earthquake, reporting such information within a year after the shock. The data provided by the RAH has been thoroughly analyzed, deriving an M S K intensity value for each one of the localities (more than 1000) included in the report, and an isoseismal map has been obtained from such values. Observations reported, such as tsunami, surface effects, duration of shaking and effects on the population are also discussed. Finally, a comparison is made of the data with the results of recent investigations on the tectonics of the region.     

Une methode de mesure de la stabilite verticale de l'atmosphere pres du sol

For a ground-level continuous release of a trace substance like ²²²Rn, for which the vertical profile of concentrations is exponential, a quantity, equivalent mixing height h, is defined in this paper in the following way. If the substance were to be redistributed uniformly through a layer such that the concentration were to be equal to that at the surface, then the top of the layer would be h.Relative values of h can be obtained from surface measurements of Radon concentrations, but absolute values require estimates of the vertical fluxes of Radon. A comparison is given of the estimates of h obtained from surface measurements with estimates derived from the vertical profile of Radon from the surface to 100 m.Practical methods are proposed for estimating the surface flux of Rn.     

Growing up with rivers? Rivers in London children's worlds

This paper presents the results from exploratory research which set out to investigate London children's perceptions and uses of river environments. Mainly qualitative, multi-method research was carried out in four primary schools with children aged 9–11, focusing on two rivers near to the schools. Rivers were found to be marginal to the children's everyday lives and outdoor play, being perceived as polluted, neglected, and initially dangerous places. However, when experienced on visits observed as part of the research, some of these perceptions changed and rivers were also found to afford many special activities and experiences for the children. The visits were generally seen to have a positive effect on the children's perceptions of rivers, at least in the short term. This suggests that, if managed appropriately, rivers could be potentially rewarding play areas for children. Moreover, children could provide valuable input for river managers in suggesting ways of improving suitable local rivers for increased recreational uses.     

A gender analysis of quality of life in Saskatoon, Saskatchewan

While many community initiatives have attempted to assess the nature and determinants of their citizens’ quality of life (QOL), these initiatives have produced little about whether the key determinants of life quality differ by gender. Using both quantitative and qualitative data from a recent QOL research project in Saskatoon, Saskatchewan, Canada, this study explores whether factors that predict poor QOL are similar for women and men. The study also examines whether the nature of these gender differences varies across low, medium and high socio-economic status locales. Results showed that men and women were very similar in: (1) their QOL ratings, (2) reports of deterioration in neighborhood QOL, and (3) rating particular aspects of their neighborhood. Few gender differences were also found when analyzing data referring to place characteristics and social cohesion. Multivariate analysis revealed further similarities: (1) being divorced/widowed was a significant predictor of poor QOL, and (2) a negative view of community security issues was associated with deterioration in perceived neighborhood quality of life. For women, however, other variables were important predictors of QOL: being middle aged, being single, and having a poor opinion of the overall quality of their neighborhood. Qualitative analysis revealed that while men and women shared concern about general areas such as safety and neighborhood supports, their perceptions of the details around these issues differed. The multi-method results suggest that urban policy actions should include a gendered discussion of common QOL issues.     

Mercury mobilization by oxidative dissolution of cinnabar (α-HgS) and metacinnabar (β-HgS)

Cinnabar (α-HgS) and metacinnabar (β-HgS) dissolved at environmentally significant rates in oxygenated slurry experiments simulating a low-flow fluvial system. Based on SO₄²⁻ production, cinnabar dissolution rates were 2.64 to 6.16 μmol (SO₄²⁻) m^− 2 day^− 1, and metacinnabar dissolution rates were 1.20 to 1.90 μmol (SO₄²⁻) m^− 2 day^− 1. Monodentate-bound thiosulfate (S₂O₃²⁻) was identified as an oxidation product on the HgS surface by ATR-IR spectroscopy based on strong infrared absorption bands in the 1140–1145 cm^− 1 and 1006–1014 cm^− 1 regions. The presence of sulfide oxidation intermediates on the HgS surface indicates that SO₄²⁻ concentration underestimates α-HgS and β-HgS dissolution in this setting. Mercury release rates during dissolution were more than two orders of magnitude less than SO₄²⁻ production, but were significant: 0.47 mg (Hg) m^− 2 y^− 1 from cinnabar [6.45 nmol (Hg) m^− 2 day^− 1], and 0.17 mg (Hg) m^− 2 y^− 1 from metacinnabar [2.29 nmol (Hg) m^− 2 day^− 1]. The Hg mobilized during α-HgS and β-HgS dissolution is sufficient to form natural Au–Hg amalgam in downstream placer settings. The proportion of mercury that is not remobilized during α-HgS and β-HgS dissolution likely adsorbs to the dissolving mercuric sulfide. Adsorption of Hg²⁺ to cinnabar was detected in situ by anodic stripping voltammetry using a cinnabar-modified carbon paste electrode following accumulation of Hg²⁺ on the electrode at open circuit potential.     

“A shovel or a shopping cart”: lessons from ten years of disaster response by a student-led volunteer group

Natural Hazards - Recent years have seen growing interest in enabling volunteers to play a more pronounced role in disaster response, and yet efforts to systematically analyse this crisis volunteer...     

Development of microbial carbonates in the Lower Cretaceous Codó Formation (north‐east Brazil): Implications for interpretation of microbialite facies associations and palaeoenvironmental conditions

The study of microbial carbonates has acquired new significance with the recognition that they retain valuable information related to biomineralization processes associated with microbial activity throughout geological time. Additionally, microbialites have a demonstrated economic potential to serve as excellent hydrocarbon reservoirs. The Lower Cretaceous Codó Formation, located in the Parnaiba Basin of north‐east Brazil, comprises a unique stratigraphic sequence of up to 20 m thick, well‐preserved carbonate microbialites. Deposited in a continental basin during the initial break up and separation of South America from Africa in the Early Cretaceous, this lacustrine carbonate sequence provides an excellent example to investigate the palaeoenvironmental conditions controlling microbialite facies development. Based on macroscopic and microscopic observations of outcrop and drill core samples, four microbialite facies (stromatolite, lamina, massive and spherulite) were defined and distinguished by textures and microbial fossil content. Changes in facies type are related to alternating palaeo‐water depths, as reflected by ⁸⁷Sr/⁸⁶Sr cycles resulting from fluctuations in the sources of meteoric water. Clumped isotope measurements of stromatolitic fabrics yield precipitation palaeo‐temperatures with an average value of 35°C. The δ¹⁸O values of bulk carbonate (?6·8 to ?1·5‰ Vienna Pee Dee Belemnite) imply precipitation from water with calculated δ¹⁸O values between ?1·6‰ and 1·8‰ Vienna Standard Mean Ocean Water, reflecting precipitation from variably modified meteoric waters. The δ¹³C values of bulk carbonate (?15·5 to ?7·2‰ Vienna Pee Dee Belemnite) indicate a significant input of carbon derived from aerobic or anaerobic respiration of organic matter. Combined, the data indicate that the evolution of the Codó Formation occurred in a closed lacustrine palaeoenvironment with alternating episodes of contracting and expanding lake levels, which led to the development of specific microbialite facies associations. The results provide new insights into palaeoenvironmental settings, biogenicity and early diagenetic processes involved in the formation of ancient carbonate microbialites and, by extension, improve the knowledge of the reservoir geology of correlative units in deep waters offshore Brazil.     

Mapping of a major paleodrainage system in eastern Libya using orbital imaging radar: The Kufrah River

Over the last few decades, remote sensing has revealed buried river channels in a number of regions worldwide, in many cases providing evidence of dramatic paleoenvironmental changes over Cenozoic time scales. Using orbital radar satellite imagery, we mapped a major paleodrainage system in eastern Libya, that could have linked the Kufrah Basin to the Mediterranean coast through the Sirt Basin, possibly as far back as the middle Miocene. Synthetic Aperture Radar images from the PALSAR sensor clearly reveal a 900 km-long river system, which starts with three main tributaries (north-eastern Tibesti, northern Uweinat and western Gilf Kebir/Abu Ras) that connect in the Kufrah oasis region. The river system then flows north through the Jebel Dalmah, and forms a large alluvial fan in the Sarir Dalmah. The sand dunes of the Calanscio Sand Sea prevent deep orbital radar penetration and preclude detailed reconstruction of any possible connection to the Mediterranean Sea, but a 300 km-long link to the Gulf of Sirt through the Wadi Sahabi paleochannel is likely. If this connection is confirmed, and its Miocene antiquity is established, then the Kufrah River, comparable in length to the Egyptian Nile, will have important implications for the understanding of the past environments and climates of northern Africa from the middle Miocene to the Holocene.     

Timing the time of concentration: shedding light on a paradox

From the origins of hydrology, the time of concentration, t_c, has conventionally been tackled as a constant quantity. However, theoretical proof and empirical evidence imply that t_c exhibits significant variability against rainfall, making its definition and estimation a hydrological paradox. Adopting the assumptions of the Rational method and the kinematic approach, an effective procedure in a GIS environment for estimating the travel time across a catchment’s longest flow path is provided. By application in 30 Mediterranean basins, it is illustrated that t_c is a negative power function of excess rainfall intensity. Regional formulas are established to infer its multiplier (unit time of concentration) and exponent from abstract geomorphological information, which are validated against observed data and theoretical literature outcomes. Besides offering a fast and easy solution to the paradox, we highlight the necessity of implementing the varying t_c concept within hydrological modelling, signalling a major shift from current engineering practices.