A texture‐based region growing algorithm for volume extraction in seismic data

We present a novel approach to automated volume extraction in seismic data and apply it to the detection of allochthonous salt bodies. Using a genetic algorithm, we determine the optimal size of volume elements that statistically, according to the U‐test, best characterize the contrast between the textures inside and outside of the salt bodies through a principal component analysis approach. This information was used to implement a seeded region growing algorithm to directly extract the bodies from the cube of seismic amplitudes. We present the resulting three‐dimensional bodies and compare our final results to those of an interpreter, showing encouraging results.     

The Role of Fault-Zone Architectural Elements on Pore Pressure Propagation and Induced Seismicity

We used hydrogeologic models to assess how fault-zone properties promote or inhibit the downward propagation of fluid overpressures from a basal reservoir injection well (150 m from fault zone, Q = 5000 m³/day) into the underlying crystalline basement rocks. We varied the permeability of the fault-zone architectural components and a crystalline basement weathered layer as part of a numerical sensitivity study. Realistic conduit-barrier style fault zones effectively transmit elevated pore pressures associated with 4 years of continuous injection to depths of approximately 2.5 km within the crystalline basement while compartmentalizing fluid flow within the injection reservoir. The presence of a laterally continuous, relatively low-permeability altered/weathered basement horizon (k_{altered layer} = 0.1 × k_basement) can limit the penetration depth of the pressure front to approximately 500 m. On the other hand, the presence of a discontinuous altered/weathered horizon that partially confines the injection reservoir without blocking the fault fluid conduit promotes downward propagation of pressures. Permeability enhancement via hydromechanical failure was found to increase the depth of early-time pressure front migration by a factor of 1.3 to 1.85. Dynamic permeability models may help explain seismicity at depths of greater than 10 km such as is observed within the Permian Basin, NM.     

Simulation of Synthetic Exploration and Geometallurgical Database of Porphyry Copper Deposits for Educational Purposes

Natural Resources Research - The access to real geometallurgical data is very limited in practice, making it difficult for practitioners, researchers and students to test methods, models and...     

Virtual tools for volcanic crisis management, and evacuation decision support: applications to El Chichón volcano (Chiapas, México)

Decision making regarding massive evacuation of a population threatened by a probable volcanic eruption is a major problem in crisis management. Such a decision is general on the number of people to be evacuated, available resources and infrastructure, quantity and quality of the escape routes and shelters, and the economic, social and political costs involved in the operation, coupled with the updated information provided by scientists about the forecast of future activity and probable eruption scenarios. Knowing time-lapse between the evacuation decision-making time and the time in which the evacuation is completed is another critical issue that must be carefully considered in densely populated areas. In such areas, it is really important to estimate in advance this time-lapse, as the forecast must be released with enough time to complete all the evacuation process before the destructive manifestations of the eruption begin. In this context, evacuation planning is a crucial component of emergency management. It is common for Emergency Plans to include pre-established strategies. However, an evacuation procedure should be flexible, depending on the above-mentioned timing, and on the decisions, evacuation schemes, environmental characteristics and other factors. In this work, several hazard models such as a lava flow model based on a Monte Carlo algorithm, a pyroclastic density current based on energy cone model, a semi-empirical inversion model to estimate the thickness of ash deposits, and all available information about the El Chión volcano have been used to obtain the area that should be evacuated in case of an eruption. Then, multiple evacuation strategies at El Chichón volcano have been designed, considering not only the characteristics of the eruption forecast, but also environmental factors (e.g., weather conditions) and social factors (e.g., tourism and farming seasons). The variable scale evacuation model has been used to estimate the evacuation time. In the paper, those virtual tools are briefly described as well as the information obtained from the drill of 2009. In addition to the optimization of evacuation under variable conditions and situations, one of the main objectives of this work is to provide a reliable estimation of the mitigation action time, for an Emergency Plan.     

Sources of surface water for the Soncor ecosystem,Salar de Atacama basin,northern Chile

Abstract

The Salar de Atacama is located in the most arid desert in the world. Despite its extreme conditions, it has many ecosystems of high ecological value. The Soncor ecosystem, a sequence of lagoons, is the most important environment of the region as it acts as the centre for the breeding of the Andean Flamingo. This salt flat also contains significant mining deposits and is an important water source for the region. Freshwater and brine—enriched in lithium and potassium—are being pumped from the aquifers near to the Soncor ecosystem, which has so far not been greatly affected by this groundwater extraction. However, there is a potential risk that future anthropogenic effects may disturb this fragile environment. The objective of this study is to determine the origin of the water sources of the Soncor ecosystem so as to adequately manage its water resources. Three hypotheses previously proposed in the technical literature were investigated in order to determine proactive actions to protect this fragile ecosystem. The study utilized classic hydrogeological techniques, such as the construction of stratigraphic profiles, piezometric maps and stream gauging, combined with less-common isotopic techniques, such as the ⁸⁷Sr/⁸⁶Sr ratio. The results confirmed the hypothesis that the origins of the water sources are associated with groundwater inputs coming from the east side of the salt flat, in the north of the basin.

Editor Z.W. Kundzewicz; Associate editor M. Acreman

Citation Ortiz, C., Aravena, R., Briones, E., Suárez, F., Tore, C., and Muñoz, J.F., 2014. Sources of surface water for the Soncor ecosystem, Salar de Atacama basin, northern Chile. Hydrological Sciences Journal, 59 (2), 336–350.     

First record of Odontaster penicillatus populations (Philippi, 1870) (Echinodermata: Asteroidea) in the Atacama and Antofagasta regions,Chile (Southeast Pacific)

We report for the first time the presence of local populations of the starfish Odontaster penicillatus in the regions of Atacama and Antofagasta, Chile. This finding indicates an extension of the distribution limit of 500 km with respect to the last observation made in 2007 in Isla Grande de Atacama. A total of 121 specimens of O. penicillatus were recorded at depths of between 8 m and 24 m. They were associated with rocky substrate and with different species of barnacles, sponges and bryozoans. The presence of O. penicillatus expands the knowledge of the benthic biodiversity of the region, and the development of studies on its ecological importance will be promoted.     

Major moisture sources for Western and Southern India and their role on synoptic‐scale rainfall events

Although the identification of the moisture sources of a region is of prominent importance to characterize precipitation, the origin and amount of moisture towards the Indian Subcontinent and its relationship with the occurrence of precipitation are still not completely understood. In this article, the origin of the atmospheric water arriving to the Western and Southern India during a period of 5 years (1 January 2000–31 December 2004) is investigated by using a Lagrangian diagnosis method. This methodology computes budgets of evaporation minus precipitation by calculating changes in the specific humidity of thousands of air particles aimed to the study area following the observed winds. During the summer monsoon, the main supply of moisture is the Somali Jet, which crosses the equator by the West Indian Ocean. The recycling process is the main water vapour source in winter. Two additional moisture sources located over northwestern India and the Bay of Bengal are identified. A 30% increase in the moisture flux from the Indian Ocean has been related to the occurrence of strong precipitation in the area, and at the end of the monsoon, the recycling became a significant contribution to the last part of the wet season of Western and Southern India. Copyright © 2011 John Wiley & Sons, Ltd.     

n-Alkan-2-ones in peat-forming plants from the Roñanzas ombrotrophic bog (Asturias, northern Spain)

We determined the distribution of lipids (n-alkanes and n-alkan-2-ones) in present-day peat-forming plants in the Roñanzas Bog in northern Spain. Consistent with the observation of others, most Sphagnum (moss) species alkanes maximized at C₂₃, whereas the other plants maximized at higher molecular weight (C₂₇ to C₃₁). We show for the first time that plants other than seagrass and Sphagnum moss contain n-alkan-2-ones. Almost all the species analysed showed an n-alkan-2-one distribution between C₂₁ and C₃₁ with an odd/even predominance, maximizing at C₂₇ or C₂₉, except ferns, which maximized at lower molecular weight (C₂₁-C₂₃). We also observed that microbial degradation can be a major contributor to the n-alkan-2-one distribution in sediments as opposed to a direct input of ketones from plants.     

Daily activity and thermoregulation in predator-prey interaction during the Flowering Desert in Chile

We studied how features of thermal resources affect the patterns of activity of predator (Callopistes maculatus) and its prey (Gyriosomus batesi and Gyriosomus subrugatus) during the phenomenon of the Flowering Desert in Chile. We predict that restrictions or variations in temperature affect mainly the activity of insects, and that this variation in the activity of insects affects the patterns of activity of the predator. The daily activity of the three species was bimodal, but both prey species disappear when temperatures exceed 40 °C. According to our results, the prey are thermoconformers to air and substrate temperature, whereas the predator is a thermoregulator to environmental conditions by their independence of air and substrate temperature.