Real system analyses/natural analogues

This paper gives an overview of the behaviour of U in two natural systems, the Forsmark site (a granitic system) in Sweden and the Ruprechtov site (a Tertiary sedimentary system) in the Czech Republic, which have been investigated in the frame of the FUNMIG project. It is not a full review paper on U geochemistry. It shows how different approaches and methods have been used to derive information on U solubility and speciation, on characteristics of key processes as well as on timescales of these processes and accordingly information on the long-term stability of U phases in the natural systems. The results are set in a wider context by relation to selected results from other sites.     

Regional co-development and security:: a comprehensive approach

Concepts of security are no longer limited to the military form, but other potential, economic, ecological, social aspects are becoming included.Emphasis needs to be put on integration of all dimensions of security. Many environmental problems present threats to human health and welfare and hence to the well-being of nations. The environmental issues cannot be ignored in context of any comprehensive security concept, but environmental security should not be treated in isolation.Integration of sustainable development and regional security may address many of the current maritime issues. Such integration may best be handled jointly and at regional levels.With this in mind and the realization that there is now a clear awareness and understanding that issues such as poverty, underdevelopment, population growth, environmental quality and sustainable resource use, are interrelated and interdependent and must be dealt with as such, the paper aims to highlight some aspects of regional security and sustainable development issues with reference to the Mediterranean basin. The aim is to initiate a process to pursue integration of sustainable development and comprehensive regional security with focus on the Mediterranean.The approach is based on the concept of the Common Heritage of Mankind as proposed by Arvid Pardo in 1967. It has 4 dimensions: economic; ethical; environmental; peace and security. In dealing with the proposal of Arvid Pardo the United Nations General Assembly decided to split up the concept: the Conference on the Law of the Sea was to deal with the peaceful uses of oceans and sea-beds; the Conference on Disarmament with the security aspects, then considered as military. UNCED 92 maintained the separation in addressing only environment and development, with management also included. However, peace and security were not included. It is time now to include these elements, and also consider the enforcement issue. The paper aims at illustrating this need through some examples from the Mediterranean basin.     

Sub-surface precipitation of salts in supercritical seawater

Extremely low solubility of typical seawater salts within certain supercritical sections of their pressure–temperature composition space is a proven experimental fact. Its consequences are often referred to as either 'shock crystallization' or 'out-salting'. Our alternative model for the formation of salt deposits hypothesizes that high temperatures and pressures characteristic for the high heat-flow zones of tectonically active basins may bring submarine brines into the out-salting regions and result in the accumulation of geological-scale salt depositions.
To confirm the laboratory observations, molecular-scale simulations (molecular dynamics) have been employed to study structural changes in a model seawater system where temperature increased from ambient to near-critical and supercritical. Fluid properties and phase transition regions extracted from the simulations were then used as input parameters for a reservoir simulator program to model out-salting in a simple hydrothermal geological system. Both numerical simulations and laboratory experiments confirm that supercritical out-salting is a viable process of geological significance for the formation and accumulation of evaporites. We suggest two regions where hydrothermally associated salts may be depositing today: Atlantis II Deep, in the Red Sea, and Lake Asale, Ethiopia.     

Statistical analysis of strong-motion accelerograms and its application to earthquake early-warning systems

In view of increasing damage due to earthquakes, and the current problems of earthquake prediction, real-time warning of strong ground motion is attracting more interest. In principle, it allows short-term warning of earthquakes while they are occurring. With warning times of up to tens of seconds it is possible to send alerts to potential areas of strong shaking before the arrival of the seismic waves and to mitigate the damage, but only if the seismic source parameters are determined rapidly. The major problem of an early-warning system is the real-time estimation of the earthquake's size.
We investigated digitized strong-motion accelerograms from 244 earthquakes that occurred in North and Central America between 1940 and 1986 to find out whether their initial portions reflected the size of the ongoing earthquake. Applying conventional methods of time-series analyses we calculate appropriate signal parameters and describe their uncertainties in relation to the magnitude and epicentral distance. The study reveals that the magnitude of an earthquake can be predicted from the first second of a single accelerogram within ±1.36 magnitude units. The uncertainty can be reduced to about ±0.5 magnitude units if a larger number (≥8) of accelerograms are available, which requires a dense network of seismic stations in areas of high seismic risk.     

Storsteinsfjellbreen: Variations in Mass Balance from the 1960s to the 1990s

When the Norwegian State Power Board decided to plan an extensive water power development in the mountainous areas southeast of Narvik in northern Norway, a large mapping project was started. Detailed maps were constructed at a scale of 1:10 000 from aerial photographs taken in 1960. Several hydrometric stations were installed, and three glaciers were selected for mass balance observations. Storsteinsfjellbreen was the largest of these, and a special glacier map with 10 m contours was printed in four colours, to be used in the field work. Mass balance studies were carried out initially during one 5-year period (1964–68), and also later during another 5-year period (1991–95).
Results from these periods are compared with similar data from the Swedish glacier Storglaciären, about 45 km to the southeast. For all the years except one (1968), the net balance of these glaciers shows a similar pattern: positive years and negative years are synchronous.
A new glacier map was made from a special aerial survey in 1993 at the same scale and of similar accuracy as the first map, so a comparison could be made to calculate the change in glacier volume from 1960 to 1993. From digital terrain models it could be shown that the glacier surface had dropped more than 60 m vertically on the tongue, while the thickness increased above the equilibrium line by up to 20 m. The overall mass loss amounted to 16.8×10⁶ m³ water during 33 years, which corresponds to an extra 2.6 l·s⁻¹·km⁻² (litres per sec. per sq. km) delivered to the river, in addition to the "normal" discharge
due to annual precipitation, which is 36 l·s⁻¹·km⁻² in the area.
A copy of the new glacier map is enclosed with this article.