Infrastructure failure interdependencies in extreme events: power outage consequences in the 1998 Ice Storm

This paper addresses the problem of interdependent failures of critical infrastructures in disasters. Disruptions to critical infrastructure systems such as electric power or transportation frequently cause major social and economic loss in disasters, both directly and through failures in one system leading to or compounding disruptions in another. Strategic approaches regarding infrastructure failures are needed to guide community mitigation and preparedness efforts. This paper defines and provides a conceptual framework for investigating infrastructure failure interdependencies (IFIs) from the standpoint of societal impacts. In order to identify empirical patterns, a unique database has been developed of IFIs observed in major electric power outage events. This paper presents analysis of this data for a major Canadian disaster, the 1998 Ice Storm that affected the northeastern region of the country. The analysis identifies IFIs due to power outage caused by the storm that are of greatest societal concern. These represent potential foci for effective, targeted pre-disaster mitigation and preparedness efforts. The framework and approach are broadly applicable across a range of natural and human-induced hazards.     

Mineral deposits and Cu–Zn–As dispersion–contamination in stream sediments from the semiarid Coquimbo Region,Chile

This paper presents Cu–Zn–As geochemical data from stream sediment surveys carried out in the three main watersheds of the Coquimbo Region of Chile. This mountainous semiarid realm occupies an area of 40,656 km² between 29° and 32°S. Given that the area has a long historical record of mining activities, important environmental disturbances were expected. However, despite the detection of three major geochemical anomalies for Cu, Zn, or As, only one can be unmistakably linked to the development of mining–metal recovery procedures (Andacollo–Panulcillo). An investigation of the other two anomalies (Elqui and Hurtado) reveals three major causes that fully or partially account for them: (1) the type of ore deposit and associated hydrothermal alteration; (2) the regional structural setting (intensity of fracturing); and (3) climate–landscape. Cu–Au–As epithermal deposits/prospects along the so-called El Indio belt are here regarded as the sources of both the Elqui and Hurtado anomalies. The strong advanced argillic alteration present in some of the epithermal deposits/prospects of the El Indio belt may have induced the loss of the buffering capacity of rocks, and therefore favoured metal dispersion during later oxidation–leaching of sulphides. This applies to the Elqui and Hurtado anomalies. Conversely, given that the potassic, propylitic and phyllic alterations do not affect the buffering capacity of rocks, only minor metal dispersion is observed in relation to the Los Pelambres porphyry copper deposit. Besides, the epithermal belt is located within a highly fractured Andean domain (3,000–4,000 m of altitude), which may have conditioned the fast unroofing of ore deposits, contributed to enhanced circulation of meteoric waters, and eventually, to strong oxidation, and leaching of metals. Metal dispersion is aggravated during rainy years in response to strong El Niño episodes.     

Measurement of natural radioactivity in sand samples collected from the Baoji Weihe Sands Park, China

The activity concentrations and the gamma-absorbed dose rates of the primordial naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were determined for sand samples collected from the Baoji Weihe Sands Park, China, using γ-ray spectrometry. The natural radioactivity concentration of sand ranges from 10.2 to 38.3 Bq kg⁻¹ for ²²⁶Ra, 27.0 to 48.8 Bq kg⁻¹ for ²³²Th and 635.8 to 1,126.7 Bq kg⁻¹ for ⁴⁰K with mean values of 22.1, 39.0 and 859.1 Bq kg⁻¹, respectively. The concentrations of these radionuclides are compared with the typical world values and the average activity of Chinese soil. The measured activity concentration of ²²⁶Ra and ²³²Th in sand is lower than the world average while that of ⁴⁰K is higher. . To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate, and the effective dose rate have been calculated and compared with internationally approved values. The radium equivalent activity values of all sand samples are lower than the limit of 370 Bq kg⁻¹. The values of the external hazard index are less than unity. The mean outdoor air absorbed dose rate is 69.6 nGy h⁻¹ and the corresponding outdoor effective dose rate is 0.085 mSv y⁻¹.     

Transport process of radionuclides in the East China Sea

Settling particles were collected from six stations at the Okinawa Trough and the East China Sea continental margin. Activities of U, Th, Pu isotopes and ^210Pb were determined for the particles to elucidate their transport processes. Surface sediment samples were also analyzed for their isotopes. There was a tendency for ^210Pb activities to increase almost linearly with depth from 72 m on the continental shelf edge to 1019 m in the Okinawa Trough. Increasing ^210Pb activities in settling particles with depth on the continental margin may be attributable to enhanced ^210Pb scavenging by particles and removal near the front. There also was a clear tendency for total mass fluxes and the radionuclide fluxes to increase with depth, with an especially large increase near the bottom. The ratio of the observed ^210Pb flux to the ^210Pb deficiency flux in the near-bottom traps ranged between 8.9 and 46. These high values show a strong ^210Pb excess which would be attributable to large advective import to the near-bottom and resuspended particles that have settled through the water column but have not been incorporated into the sediments. High variability of radionuclide fluxes occurred in very short time periods. Activities of ^238U, ^232Th, ^230Th, ^228Th, ^210Pb and ^239Pu＋^240Pu in settling particles were significantly higher than those in the underlying surface sediments.     

美国Culberson重晶石-硫磺矿中流体包裹体的研究

Culberson自然硫-重晶石矿床位于美国德克萨斯州的Delaware油气盆地中,是北美最大的自然硫矿床。它产在晚二叠世Ochoan期的Castile组和Salado组的石灰宕夹薄层蒸发岩和有机质灰岩中,重晶石和自然硫是后生的,常交代这两个组地层中的蒸发岩和富含有机质的灰岩,并填充在古喀斯特中。流体包裹体的研究表明：有两个世代的包裹体,即成岩时和方解石后生加大和重晶石中捕获的石油包裹体和流体包裹体。按包裹体的成分和相态可分为一相液体包裹体、二相气液体包裹体和油气包裹体。研究表明,在方解石、重晶石和天青石的同一生长带中可见到含有不同气液比的流体包裹体、空的包裹体和油气包裹体,它们是在一个不混溶的环境中捕获的,因而其均一温度的测定并不可靠。流体包裹体的T_e在-18℃～-24℃之间,属于NaCl- H_2O体系,盐度为2%～10%。有许多油气包裹体,因而其成矿流体应是一个温度小于100℃的油田水．     

Origine des eaux des émergences karstiques chlorurées du Languedoc-Roussillon

The origin of chloride-rich karstic spring waters representative of the Languedoc-Roussillon region has been investigated with a hydrochemical approach. To this end, the major and trace elements most often used in the study of saline environments have been considered (Cl, SO₄, Br, B, Li). This study allowed distinguishing the different end-members of the various chloride-rich karstic spring waters (evaporitic, marine, geothermal). Associated with the Cl, Br and B contents, the Li/SO₄ ratio appeared as a relevant tracer for the determination of the origin of lithium and by extension of the considered waters. To cite this article: O. Hébrard et al., C. R. Geoscience 338 (2006).     

The mobilization of debris flows from shallow landslides

According to critical state theory, a soil will approach a critical void ratio during shear such that loose soils contract and dense soils dilate. Theory indicates that failing soils must be loose to generate the pore pressures needed for the mobilization of debris flows. Previously published results from large-scale experiments have also suggested that soils must be initially loose to fail as debris flows. In this contribution, this mechanism for soil liquefaction is tested in the field through observations and geotechnical analysis of soils that failed during a large storm in central California. Surprisingly, we find that the debris flows mobilized from soils that were initially dense. In addition, we find that the potential for debris flow mobilization was strongly linked to the fines/sand ratio. We present results from a numerical model that indicate that, as dilational soils approach the critical void ratio, the arresting effect of negative pore pressures generated by dilation is greatly reduced, leading to a rapid increase in basal pore pressure and rapid downslope acceleration. In addition, the model results suggest that the downslope displacement required to reach the critical state porosity in a dilative soil will be on the order of 0.1 to 1 m. Because the rate of the approach to critical state is fundamentally a function of the hydraulic conductivity of the soil, sandy soils will approach critical state much more rapidly than clay-rich soils.     

Inversion of titanomaghemite in oceanic basalt during heating

We studied the change of magnetic behaviour upon laboratory heating of altered mid-ocean ridge basalt (MORB) samples in the age range of 16-35 Ma to determine the influence of titanomaghemite inversion on the thermal demagnetisation of natural remanent magnetisation (NRM) of these basalts. MORB samples were heated to successively higher temperatures and at the same time the temperature dependence of either saturation magnetisation or NRM was monitored continuously. After each heating step, hysteresis loops and remanent magnetisation curves between 10 K and room temperature were measured. With this procedure, it is shown that the dominant magnetic remanence carrier in our MORB samples is cation deficient titanomaghemite. Moreover, it is demonstrated that the titanomaghemite is gradually changing to a Ti-poor titanomagnetite as the final inversion product. During inversion, both the Curie temperature as well as the maximum unblocking temperature of the NRM are gradually increasing. We show that the paradox of unblocking temperatures above the Curie temperatures often observed for altered MORBs is an artefact of this gradual, heating induced inversion process.     

低能自然γ能谱测量的初步研究

提出在全谱测量基础上对自然γ能谱的低能谱段进行研究，将天然γ射线谱的低能部分看作是天然γ射线与物质作用的结果，增加反映岩石物质成分的参数。这样，测量结果提供的不仅有放射性元素分布的数据，而且还有直接反映岩性变化的资料，可用于地质填图及金属矿地质工作。     

Preliminary results of environmental monitoring of the natural gas hydrate production test in the South China Sea

Natural gas hydrate (NGH) is considered as one of the new clean energy sources of the 21st century with the highest potential. The environmental issues of NGH production have attracted the close attention of scientists in various countries. From May 10 to July 9, 2017, the first offshore NGH production test in the South China Sea (SCS) was conducted by the China Geological Survey. In addition, environmental security has also been effectively guaranteed via a comprehensive environmental monitoring system built during the NGH production test. The monitoring system considered sea-surface atmosphere methane and carbon dioxide concentrations, dissolved methane in the sea water column, and the seafloor physical oceanography and marine chemistry environment. The whole process was monitored via multiple means, in multiple layers, in all domains, and in real time. After the production test, an environmental investigation was promptly conducted to evaluate the environmental impact of the NGH production test. The monitoring results showed that the dissolved methane concentration in seawater and the near-seabed environment characteristics after the test were consistent with the background values, indicating that the NGH production test did not cause environmental problems such as methane leakage.