Hazard assessment at San Martín volcano based on geological record, numerical modeling, and spatial analysis

The San Martín shield volcano, located in the Los Tuxtlas Volcanic Field, has experienced effusive shield-building activity, as well as explosive eruptions, as evidenced by direct observations during the last eruption in 1793. The threat to the surrounding villages consists principally of lahars, especially because of the tropical climate in the region. Ash fallout and lava flows represent additional hazards. In addition, the surrounding Quaternary monogenetic field includes more than 300 scoria cones and about 40 explosion craters (mainly maars) that also represent a hazard source. In the present study we constructed hazard maps using field data, orthophotos, spatial analysis, and specialized software (LAHARZ and HAZMAP) to deliminate lahar inundation zones, areas that could potentially be affected by ash fallout (including the evaluation of houses prone to roof collapse due to ash load), and the most susceptible areas for hosting future monogenetic vent formation.     

Growing Operational Use of FY-3 Data in the ECMWF System

This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4.     

Organic sedimentary deposits in Titan’s dry lakebeds: Probable evaporite

We report the discovery of organic sedimentary deposits at the bottom of dry lakebeds near Titan’s north pole in observations from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). We show evidence that the deposits are evaporitic, making Titan just the third known planetary body with evaporitic processes after Earth and Mars, and is the first that uses a solvent other than water.     

Governance arrangements targeting diversity in Europe: how New Public Management impacts working with social cohesion

This article analyses how policies to foster social cohesion within diverse and unequal urban contexts are affected by New Public Management and austerity policies. Based on the analysis of a handful of governance arrangements in three cities that differ in their institutional structure and diversity policy approaches (Copenhagen, Leipzig and Milan), it is shown that negative effects are quite widespread yet cushioned by a strong welfare state structure, solid local government and high priority given to the recognition of diversity. Nevertheless, the shift towards the application of market logic to social work reduces innovative potential, increases efforts spent on procedures and weakens public coordination.     

Natural analogues: a potential approach for developing reliable monitoring methods to understand subsurface CO2 migration processes

One possible way of mitigating carbon dioxide (CO₂) emissions from fossil fuel combustion is using carbon dioxide capture and storage (CCS) technology. However, public perception concerning CO₂ storage in the geosphere is generally negative, being particularly motivated by perceived leakage risks. Therefore, a main issue when attempting to gain public acceptance is ensuring provision of appropriate monitoring practices, aimed at providing health, safety and environmental risk assessment, so that potential risks from CO₂ storage are minimized. Naturally occurring CO₂ deposits provide unique natural analogues for evaluating and validating methods used for the detection and monitoring of CO₂ spreading and degassing into the atmosphere. Geological and hydrological structures of the Cheb Basin (NW Bohemia, Czech Republic) represent such a natural analogue for investigating CO₂ leakage and offer a perfect location at which to verify monitoring tools used for direct investigation of processes along preferential migration paths. This shallow basin dating from the Tertiary age is characterized by up to 300?m thick Neogene sediment deposits and several tectonically active faults. The objectives of this paper are to introduce the CO₂ analogues concept to present the Eger Rift as a suitable location for a natural CO₂ analogue site and to demonstrate to what extent such an analogue site should be used (with a case study). The case study presents the results obtained from a joint application of geoelectrical measurements in combination with soil CO₂ concentration and flux determination methods, for the detection and characterization of natural CO₂ releases at gas seeps (as part of a hierarchic monitoring concept). To highlight discharge-controlling structural near surface features was the initial motivation for the application of geoelectrical measurements. Soil-gas concentration and flux measurement techniques are relatively simple to employ and are valuable methods that can be used to monitor seeping CO₂ along preferential pathways. Joint interpretation of both approaches yields a first insight into fluid paths and reveals that the thickness and permeability of site-specific near surface sedimentary deposits have a great influence upon the spatial distribution of the CO₂ degassing pattern at surface level.     

A Comparative Study of Different Approaches for Factor of Safety Calculations by Shear Strength Reduction Technique for Non-linear Hoek–Brown Failure Criterion

The shear strength reduction technique is becoming more and more popular to determine the factor-of-safety for geotechnical constructions, especially for slopes. At present, two in principal different procedures are used to apply the numerical shear strength reduction technique for materials characterised by non-linear failure envelopes, like the Hoek–Brown criterion. One procedure is based on the determination on local stress and strength values, whereas the other is based on a global linearization of the non-linear failure envelope. This article shortly describes and discusses these two different procedures and compares results for a broad spectrum of parameter constellations based on slope stability calculations. The local approach is physically more correct. The global approach can be considered as a first approximation. A comparison of both methods reveal that the global approach in comparison to the local approach, can leads to a deviation of up to 15?% in both directions. If one considers the local approach as the ‘correct’ one, depending on the parameters the results of the global approach can lie on the safe or unsafe site. The practical conclusion is that evaluation of slope stability using the global approach can result in uneconomic slope design or overestimation of safety margin. The use of the local approach instead of the global should be preferred. In case of small safety margins (e.g. 20?% or less) the use of the local approach is strictly recommended.