Economic region net migration patterns in the USSR: 1979-89

"This article investigates economic region net migration patterns in the USSR during the 1979-89 intercensal period. Net in-migration and net migration rate increases (compared to 1970-79) occurred in both the western and eastern portions of the Northern USSR region, while net out-migration and rate declines occurred throughout the Southern USSR. Net in-migration again occurred to Siberia, especially Tyumen' Oblast, and there was a reduced rate of net out-migration from the Nonchernozem Zone and Central Chernozem Region of European RSFSR."     

Biogenic and pollutant aliphatic hydrocarbons in Mytilus edulis from the North Sea

Capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) have been used to examine the aliphatic hydrocarbon fraction of specimens of the mussel, Mytilus edulis, collected from the legs of a North Sea oil-production platform. In addition to an unresolved complex mixture (UCM) of fossil fuel pollutant hydrocarbons (ca. 64 μg g^?1 dry weight average), the fraction was dominated by large amounts (ca. 21 μgg^?1 dry weight) of C₃₁ and C₃₃n-alkenes with 2, 3 and 4 double bonds. These alkenes have also been identified in the ubiquitous marine alga, Emiliania huxleyi, and in some species of fish taken from the North Sea. The close correspondence in the composition data suggest that, in the mussel, these alkenes arise from a biogenic dietary source, most probably from Emiliania huxleyi. This contention is supported by the identification in the mussel of unusual C₃₇, C₃₈ and C₃₉ unsaturated straight-chain ketones which have recently been shown to be biosynthesised by Emiliania.     

World-wide increase in tropospheric methane, 1978–1983

Tropospheric concentrations of methane in remote locations have averaged a yearly world-wide increase of 0.018±0.002 parts per million by volume (ppmv) during the period from January 1978 to December 1983. The concentrations in the north temperate zone are always greater than those in the south temperate zone by 7±1% because the major methane sources are all predominantly located in the northern hemisphere. The average world-wide tropospheric concentration of methane in dry air was 1.625 ppmv at the end of 1983, measured against an NBS standard certified as 0.97 ppmv (but with an accuracy of only ±1%). The world-wide concentration increases are described by a linear equation with a standard deviation of 0.003 ppmv for ten different collection periods during 1978–1983. The precision of measurement of the methane concentration in the atmospheric samples and in the standard was measured to be ±0.4% for each. Repetitive measurements of an air sample collected in November 1977 have shown the same concentration for six years with a standard deviation for these data of ±0.003 ppmv.The causes for the steady increase in methane concentration in the troposphere cannot be fixed with certainty from present data. Contributing causes can include increases in the source strengths from cattle and rice fields. The atmospheric concentrations of CO, CH₄ and HO are all closely coupled with one another, and increased concentrations of CO and/or CH₄ should cause reduced concentrations of HO, which in turn should lengthen the atmospheric lifetimes of CO and CH₄.Among other physical and chemical effects, a increase of 0.18 ppmv per decade should contribute a greenhouse warming of about 0.04°C per decade. Other secondary contributions to the greenhouse effect from increases in CH₄ may arise from methane-induced increases in stratospheric H₂O, in tropospheric O₃, and in numerous other trace species whose concentration is controlled by reaction with HO radicals.An increased CH₄ source strength may result from the effect of increasing atmospheric temperatures on the known aqueous biological CH₄ sources, such as swamps, and may be an added consequence of the greenhouse effect.     

The changing morphology of an open lava channel on Mt. Etna

An open channel lava flow on Mt. Etna (Sicily) was observed during May 30–31, 2001. Data collected using a forward looking infrared (FLIR) thermal camera and a Minolta-Land Cyclops 300 thermal infrared thermometer showed that the bulk volume flux of lava flowing in the channel varied greatly over time. Cyclic changes in the channel's volumetric flow rate occurred over several hours, with cycle durations of 113–190 min, and discharges peaking at 0.7 m³ s⁻¹ and waning to 0.1 m³ s⁻¹. Each cycle was characterized by a relatively short, high-volume flux phase during which a pulse of lava, with a well-defined flow front, would propagate down-channel, followed by a period of waning flow during which volume flux lowered. Pulses involved lava moving at relatively high velocities (up to 0.29 m s⁻¹) and were related to some change in the flow conditions occurring up-channel, possibly at the vent. They implied either a change in the dense rock effusion rate at the source vent and/or cyclic-variation in the vesicle content of the lava changing its bulk volume flux. Pulses would generally overspill the channel to emplace pāhoehoe overflows. During periods of waning flow, velocities fell to 0.05 m s^–1. Blockages forming during such phases caused lava to back up. Occasionally backup resulted in overflows of slow moving ‘a‘ā that would advance a few tens of meters down the levee flank. Compound levees were thus a symptom of unsteady flow, where overflow levees were emplaced as relatively fast moving pāhoehoe sheets during pulses, and as slow-moving ‘a‘ā units during backup. Small, localized fluctuations in channel volume flux also occurred on timescales of minutes. Volumes of lava backed up behind blockages that formed at constrictions in the channel. Blockage collapse and/or enhanced flow under/around the blockage would then feed short-lived, wave-like, down-channel surges. Real fluctuations in channel volume flux, due to pulses and surges, can lead to significant errors in effusion rate calculations. Editorial responsibility: A. Woods     

The 1919–1920 eruption of Mauna Iki,Kilauea: chronology,geologic mapping,and magma transport mechanisms

Utilizing historical accounts, field mapping, and photogeology, this paper presents a chronology of, and an analysis of magma transport during, the December 1919 to August 1920 satellitic shield eruption of Mauna Iki on the SW rift zone of Kilauea Volcano, Hawaii. The eruption can be divided into four stages based on the nature of the eruptive activity. Stage 1 consisted of the shallow injection of a dike from the summit region to the eventual eruption site 10 km downrift. During stage 2, a low ridge of pahoehoe formed in the vent area; later a large a'a flow broke out of this ridge and flowed 8.5 km SW at an average flow front velocity of 0.5 km/day. The eruption continued until mid-August producing almost exclusively pahoehoe, first as gas-rich overflows from a lava pond (stage 3), and later as denser tube-fed lava (stage 4) that reached almost 8 km from the vent at an average flow-front velocity of 0.1 km/day. Magma transport during the Mauna Iki eruption is examined using three criteria: (1) eruption characteristics and volumetric flow rates; (2) changes in the surface height of the Halemaumau lava lake; and (3) tilt measurements made at the summit of Kilauea. We find good correlation between Halemaumau lake activity and the eruptive stages. Additionally, the E-W component of summit tilt tended to mimic the lake activity. The N-S component, however, did not. Multiple storage zones in the shallow summit region probably accounted for the decoupling of E-W and N-S tilt components. Analysis of these criteria shows that at different times during the eruption, magma was either emplaced into the volcano without eruption, hydraulically drained from Halemaumau to Mauna Iki, or fed at steady-state conditions from summit storage to Mauna Iki. Volume calculations indicate that the supply rate to Kilauea during the eruption was around 3 m³/s, similar to that calculated during the Mauna Ulu and Kupaianaha shield-building eruptions, and consistent with previously determined values of long-term supply to Kilauea.     

Thick lava flows of Karisimbi Volcano, Rwanda: insights from SIR-C interferometric topography

 We use a digital elevation model (DEM) derived from interferometrically processed SIR-C radar data to estimate the thickness of massive trachyte lava flows on the east flank of Karisimbi Volcano, Rwanda. The flows are as long as 12 km and average 40–60 m (up to >140 m) in thickness. By calculating and subtracting a reference surface from the DEM, we derived a map of flow thickness, which we used to calculate the volume (up to 1 km³ for an individual flow, and 1.8 km³ for all the identified flows) and yield strength of several flows (23–124 kPa). Using the DEM we estimated apparent viscosity based on the spacing of large folds (1.2×10¹² to 5.5×10¹² Pa s for surface viscosity, and 7.5×10¹⁰ to 5.2×10¹¹ Pa s for interior viscosity, for a strain interval of 24 h). We use shaded-relief images of the DEM to map basic flow structures such as channels, shear zones, and surface folds, as well as flow boundaries. The flow thickness map also proves invaluable in mapping flows where flow boundaries are indistinct and poorly expressed in the radar backscatter and shaded-relief images. Received: 6 September 1997 / Accepted: 15 May 1998     

A framework for resolving the transboundary water allocation conflict conundrum

This paper describes a methodology for resolving transboundary water disputes that arise when people/states/nations sharing a resource that crosses legal/political jurisdictions disagree about the use of the resource. Laws and treaties written in an attempt to settle disputes are frequently neither enforced nor effective, and disagreements continue. Crises, arising through resource overuse or shortages, worsen the conflict and typically result in further discord, lawsuits, depletion of the resource, and even open-armed hostility. Many water management experts call for either private/market-based or state/command-and-control resource management systems, but these eventually break down during crisis. The crises therefore necessitate the adoption of a more effective institutional arrangement to address and resolve present and future problems. A better alternative to management by private or state entities and the resolution of conflicts by the mere application of law is a cooperative approach. The Rowland-Ostrom Framework, introduced in this paper, incorporates Ostrom's eight design principles for sustainable common pool resource management within the context of crisis that involves an urgent threat to the quantity or quality of a resource such as water, as described by the author. This paper demonstrates that although established 15 years ago, Ostrom's design principles remain applicable today for effective, sustainable transboundary water management, and the Rowland-Ostrom Framework is a model for the equitable use of shared water resources throughout the world.     

Variations in distributions of C25 highly branched isoprenoid (HBI) alkenes in the diatom, Haslea ostrearia: influence of salinity

C₂₅ HBI alkenes of the diatom, Haslea ostrearia, have been examined in experiments in which the algae were cultured for up to 10 days at 14–15°C at nine different salinities (15 to 40 per mil). H. ostrearia proved to be an osmotolerant organism and growth was observed at all salinities. After 10 days growth at the lowest and highest salinities of 15 and 40 per mil, the concentrations of 2,10,14-trimethyl-6-methylene-7-(3-methylpent-1-enyl)pentadec-9-ene, which was the only HBI present in any of the samples, averaged 1.2±0.7 and 2.1±0.7 pg cell⁻¹, respectively. These were slightly lower than the HBI concentrations at 25 to 35 per mil (2.8±0.5 pg cell⁻¹). The data indicate that although salinity has an influence on HBI production in H. ostrearia, factors other than salinity are probably more important in controlling the large variations of HBI alkene concentrations and distributions found in sedimentary environments.     

Aspects of the differences in the erodibility of the waste rock dump and natural surfaces, Ranger Uranium Mine, Northern Territory, Australia

Small-scale flume experiments on the waste rock dump of Ranger Uranium Mine, Northern Territory, Australia, show that the unmanaged surface of the dump is 10–100 times more erodible than adjacent natural hillslopes. Silt and clay are preferentially removed and their proportion of the total sediment load is enhanced over their content in surface sediment. There is strong evidence that a low threshold of erosion does not exist and that even the smallest of flows across the waste rock dump can erode and transport some surface material. The erodible dump surface and the preferential removal of silt-clay could degrade ecosystems both on the dump and off-site. Rehabilitation of the waste rock dump will require special attention to erosion and its management.