Earthquake early warning and operational earthquake forecasting as real-time hazard information to mitigate seismic risk at nuclear facilities

Based on our experience in the project REAKT, we present a methodological framework to evaluate the potential benefits and costs of using earthquake early warning (EEW) and operational earthquake forecasting (OEF) for real-time mitigation of seismic risk at nuclear facilities. We focus on evaluating the reliability, significance and usefulness of the aforementioned real-time risk-mitigation tools and on the communication of real-time earthquake information to end-users. We find that EEW and OEF have significant potential for the reduction of seismic risk at nuclear plants, although much scientific research and testing is still necessary to optimise their operation for these sensitive and highly-regulated facilities. While our test bed was Switzerland, the methodology presented here is of general interest to the community of EEW researchers and end-users and its scope is significantly beyond its specific application within REAKT.     

Mineralogy, Lithogeochemistry and Elemental Mass Balance of the Hydrothermal Alteration Associated with the Gold-rich Batu Hijau Porphyry Copper Deposit, Sumbawa Island, Indonesia

This paper discusses the mineralogy, whole-rock geochemistry and elemental mass balance of the hydrothermal alteration zones within the Batu Hijau porphyry copper-gold deposit, Sumbawa Island, Indonesia. The hydrothermal alteration and mineralisation developed in four stages, namely (i) the early stage consisting of a central copper-gold-bearing biotite (potassic), proximal actinolite (inner propylitic) and the distal chlorite-epidote (outer propylitic) zones; (ii) the transitional stage represented by the chlorite-sericite (intermediate argillic) zone; (iii) the late stages distinguished into the sericite-paragonite (argillic) and pyrophyllite-andalusite (advanced argillic) zones; and (iv) the very late stage typified by the illite-sericite zone. In general, major elements (particularly Ca, Mg, Na and K) and some minor and rare earth elements decrease from the least altered rocks towards the late alteration zones as a consequence of the breakdown of Ca-bearing hornblende, biotite and plagioclase. Chemical discrimination by means of millicationic R₁-R₂ diagram indicates that R1 [4Si − 11(Na + K) − 2(Fe + Ti)] increases while R₂[6Ca + 2Mg + Al] decreases with increasing alteration intensity, from least-altered, through early, transitional, to late alteration zones. Rare earth elements-chondrite (C₁) normalised patterns also exhibit the depletion of the elements through the subsequent alteration zones. These results are consistent with the elemental mass balance calculation using the isocon method which shows that the degree of mass and volume depletion systematically increases during alteration. A decrease of the elements as well as mass and volume from early, through transitional to late alteration stages may imply a general decrease of the element activities in hydrothermal fluids during the formation of the alteration zones.     

Groundwater and surface-water interactions and impacts of human activities in the Hailiutu catchment,northwest China

The interactions between groundwater and surface water have been significantly affected by human activities in the semi-arid Hailiutu catchment, northwest China. Several methods were used to investigate the spatial and temporal interactions between groundwater and surface water. Isotopic and chemical analyses of water samples determined that groundwater discharges to the Hailiutu River, and mass balance equations were employed to estimate groundwater seepage rates along the river using chemical profiles. The hydrograph separation method was used to estimate temporal variations of groundwater discharges to the river. A numerical groundwater model was constructed to simulate groundwater discharges along the river and to analyze effects of water use in the catchment. The simulated seepage rates along the river compare reasonably well with the seepage estimates derived from a chemical profile in 2012. The impacts of human activities (river-water diversion and groundwater abstraction) on the river discharge were analyzed by calculating the differences between the simulated natural groundwater discharge and the measured river discharge. Water use associated with the Hailiutu River increased from 1986 to 1991, reached its highest level from 1992 to 2000, and decreased from 2001 onwards. The reduction of river discharge might have negative impacts on the riparian ecosystem and the water availability for downstream users. The interactions between groundwater and surface water as well as the consequences of human activities should be taken into account when implementing sustainable water resources management in the Hailiutu catchment.     

The acceleration and the deceleration of the tumbling period of Rocket Intercosmos 11 during the first two years after launch

We have analysed the development of the tumbling period of Rocket Intercosmos 11 (1974-34-B) during the first 2 years after launch. We interpret the period increase, observed from August 1974 to June 1976, as being caused by torque moments due to eddy currents induced in the hollow cylinder by the magnetic field of the Earth. The spin-decay time of 1974-34-B was 1.13 yr. This compares well to results derived by Williams and Meadows in 1978 for other Soviet rocket bodies.The tumbling acceleration of 1974-34-B, observed in June 1974, is interpeted as outgassing effect of rest propellant which remained inside the rocket after burn-off. A model of the outgassing acceleration is developed and compared to the period measurements of 1974-34-B. A reasonable good agreement between observed and predicted periods can be derived by using a nonlinear regression fit. An initial mass ratio of the rest propellant and the empty rocket cylinder is estimated.     

Magmatic and metamorphic evolution of metagabbros in the Münchberg Massif,N.E. Bavaria

The central gneiss complex of the Münchberg Massif consists of the Liegendserie at the base and the Hangendserie at the top. Metagabbros are found in the Liegendserie; eclogites occur in the Hangendserie. New isotope data revive the discussion whether a genetic relationship exists between metagabbros and eclogites in the Münchberg Massif. It is possible to relate the two types of rocks to the same protoliths by variable degrees of crustal contamination and magmatic accumulation. Therefore, a common magmatic origin may be assumed. Both the metagabbros and the eclogites were affected by amphibolite-facies metamorphism. The amphibolitization of the metagabbros was a prograde metamorphic event. Increasing temperature is indicated by inverse zonation of recrystallized plagioclase and increasing Mg/Fe ratios in garnet from core to rim. Geothermobarometry yields a temperature of 600°C and a pressure of about 11 kbar for the peak of metamorphism. In contrast, the eclogites underwent a first high-pressure stage at a minimum pressure of 14 kbar and a temperature estimated at 600°C and were subsequently overprinted under amphibolite-facies conditions at 10 kbar/700°C. A common magmatic origin of metagabbros (Liegendserie) and eclogites (Hangendserie) of the Münchberg Massif can no longer be discarded. However, the converging P-T-t paths reflect a different geodynamic evolution of the Liegendserie and the Hangendserie after magmatism and before amphibolite-facies metamorphism.     

Crystal chemistry of Fe-Mg-carpholites

A chemical and X-ray investigation of the Fe-Mg-carpholites of Crete/Greece reveals a large variation in their Fe²⁺/(Fe²⁺+Mg) ratios (0.68 to 0.05). The lattice constants a and b depend linearly on this parameter, and the magnitude of the effect is comparable to that encountered in pyroxenes. The similar behaviour of the lattice dimensions of both these minerals is explained by comparing their structures and pointing out the salient crystal chemical similarities.     

The mean coronal magnetic field determined from HELIOS Faraday rotation measurements

Coronal Faraday rotation of the linearly polarized carrier signals of the HELIOS spacecraft was recorded during the regularly occurring solar occultations over almost a complete solar cycle from 1975 to 1984. These measurements are used to determine the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3–10 solar radii, i.e., the range over which the complex fields at the coronal base are transformed into the interplanetary spiral. The mean coronal magnetic field in 1975–1976 was found to decrease with radial distance according to r ^–, where = 2.7 ± 0.2. The mean field magnitude was 1.0 ± 0.5 × 10 ^–5 tesla at a nominal solar distance of 5 solar radii. Possibly higher magnetic field strengths were indicated at solar maximum, but a lack of data prevented a statistical determination of the mean coronal field during this epoch.     

Integration of multi-sensor data for landscape modeling using a region-based approach

The increased availability of multi-sensor data, and elevation information in particular, leads to the need of advanced processing methods. In the context of landscape modeling tasks, we concentrate on one central component, the extraction of terrain surface from a Digital Surface Model (DSM). In contrast to conventional mathematical grey value morphology approaches (filtering methods) or to stochastical procedures, we propose an alternative methodology for this task by applying a region-based and multi-scale approach. It consists of segmentation and follow-up fuzzy logic classification based on several features derived from elevation and multi-spectral image data. The satisfying results obtained with a multi-sensor as well as with other datasets show the applicability of the approach.