A guano‐derived δ13C and δ15N record of climate since the Medieval Warm Period in north‐west Romania          下载免费PDF全文

Daniel M. Cleary  Bogdan P. Onac  Ioan Tanţău  Ferenc L. Forray  Jonathan G. Wynn  Monica Ionita  Tudor Tămaş 《第四纪科学杂志》2018,33(6):677-688

  相似文献   

Classification of Tsunami and Evacuation Areas   总被引：3，自引：2，他引：1  

Tomoya Shibayama  Miguel Esteban  Ioan Nistor  Hiroshi Takagi  Nguyen Danh Thao  Ryo Matsumaru  Takahito Mikami  Rafael Aranguiz  Ravindra Jayaratne  Koichiro Ohira 《Natural Hazards》2013,67(2):365-386

On March 11, 2011, a large earthquake that occurred offshore the north-east coast of Japan generated a large tsunami which devastated extensive areas of the Tohoku coastline. Despite Japan being considered a country well prepared for these types of disasters, large casualties were recorded, with numerous discussions amongst the Japanese coastal engineering community ensuing. As a result, two different levels of tsunamis have been proposed and now recognized in Japan, depending on the frequency of such extreme events. The idea that hard measures can protect the lives of inhabitants of coastal areas has been abandoned, and these measures are only considered to be effective in protecting properties against the more frequent but lower magnitude events. Soft measures should always be used to protect against the loss of lives, and to this respect, the authors of the paper propose the introduction of a Classification of Evacuation Areas, to show which of these should be prioritized by residents as they seek to evacuate.  相似文献   

The effects of the July 2005 catastrophic inundations in the Siret River��s Lower Watershed, Romania     

Gheorghe Romanescu  Ioan Nistor 《Natural Hazards》2011,57(2):345-368

The Siret River originates from the Wooded Carpathians (Ukraine) and has a length of 559 km on the Romanian territory. The upper river course is set on the Ukrainian territory, the middle course flows through the Suceava Tableland, and then the limit between the Moldavian Subcarpathians and the Bârlad Tableland, followed by the lower course crosses the Inferior Siret Plain. The hydrographical network includes 1,013 water tributaries (representing the richest river from this point of view in Romania) and has a length of 15,157 km, which represents 19.2% of the total length of the Romanian river network. This materializes in a density of 0.35 km/km², compared to 0.33 km/km² which is the average for Romania. The Siret River has the greatest watershed area, with a total surface of 42,890 km², which represents 18.1% of the Romanian territory. Its discharge is the highest of all internal rivers of Romania, with an average discharge of 210 m³/s at the river mouth, and this is caused by the fact that most of the tributaries come from mountainous sectors, namely the Eastern Carpathians. In the summer of 2005, the most powerful floods ever occurred in the Siret River watershed with significant negative effects on the country??s economy. Considering the multiannual average discharge of 210 m³/s, the maximum discharge recorded on July 16, 2005, was of 4,650 m³/s at Lungoci. The main cause of these events is the deforestation of the small watersheds located in the mountainous sector of the counties of Vrancea, Bacau and Neamt. The total surface affected by floods was of 58,323.936 hectares, of which: 34,142.349 ha (58.54%) arable land, 6,697.486 ha (11.48%) orchards and wine-growing plantations, 1,863.698 ha (3.20%) built areas, 2,866.313 ha (4.91%), forests 4,915.985 ha (8.43%), waters 2,081.047 ha (3.57%), and unproductive land 5,757.058 ha (9.87%). Besides the material losses (over 10,000 houses completely destroyed), 24 human deaths were recorded together with the loss of thousands of domestic animals, whose overall value exceeded two million Euros. The estimation of the extent of the flooding and its impact in the Siret River watershed has been performed using LANDSAT TM 2003 satellite images and the FAO-LCCS classification methodology, in the ASR-CRUTA remote sensing laboratory, with the images offered after activating the International CHARTER (Call ID-98).  相似文献   

Maladaptive trajectories of change in Makira, Solomon Islands   总被引：2，自引：0，他引：2  

Ioan Fazey  Nathalie Pettorelli  Jasper Kenter  Daniel Wagatora  Daniel Schuett 《Global Environmental Change》2011,21(4):1275-1289

Trajectories of change are dynamic processes of individual, group and/or societal responses to change which create further change and responses, with outcomes that reflect the cumulative properties of those processes. Understanding trajectories of change is an important initial step for designing appropriate adaptation strategies because even though responses may enable people to cope with change in the short term, the accumulated responses of individuals can generate undesirable maladaptive outcomes over longer periods of time. This paper examines trajectories of change in Kahua, Solomon Islands, where people have traditionally relied on subsistence activities and have in the past been subsistence affluent. Participatory methods, including 76 focus group discussions in 38 communities with 821 individuals, were used to determine changes in the region and its drivers. A conceptual model was developed of the underlying feedback processes within the Kahua social–ecological system. The results show that communities are facing rapid and extensive changes. Most changes, however, are being driven by the two key drivers of population growth and a strong desire for monetary prosperity that act synergistically to generate stress in communities. People are generally responding by focusing on income generation, which is reinforcing stress in communities and resulting in maladaptive trajectories of change. The results suggest development policy in the Solomon Islands needs to: (1) take the challenges of population growth much more seriously; (2) place greater effort on development activities that reduce per capita impact on the environment; (3) improve management of the high expectations for monetary prosperity; (4) increase emphasis on wellbeing aspects of development rather than income generation per se, and (5) better align development with existing adaptation strategies to ensure that vulnerability to future global change does not increase.  相似文献   

Towards Geospatial Queries in a Semantic Digital Library for 3D Data     

Ioan Marius Bilasco  Jérôme Gensel  Marlène Villanova-Oliver  Hervé Martin 《Transactions in GIS》2007,11(3):337-353

  相似文献   

A weakly non-adiabatic one-zone model of stellar pulsations: application to Mira stars     

Andreea Munteanu  Enrique García-Berro  Jordi José 《Monthly notices of the Royal Astronomical Society》2003,341(3):855-862

  相似文献   

Coping with water scarcity: the case of the Calnistea catchment (Romania)     

Alina Cocos  Octavian Cocos  Ioan Sarbu 《Environmental Earth Sciences》2012,67(3):641-652

The Calnistea catchment lies in the southern part of Romania in a region that has been confronted lately with serious water scarcity problems generated primarily by summer heat waves and long periods of drought. The high temperatures, excessive evapotranspiration and scant precipitation have a negative impact on water resources and especially on the river system, which is at the mercy of meteorological conditions, because all the streams in the area originate in the plain. Consequently, mean annual discharges are very low and more often than not, many rivers run dry. In order to avoid such an unwanted phenomenon people have built earth dams across the valleys thus creating chains of ponds, which are used to regulate the flow. Even so, however, most of the years the rivers look like mere threads of water oozing gently through their sediments. Under the circumstances, it is no wonder that irrigation systems are missing, which explains the low agricultural productivity. The most important asset of the region is the groundwater, as it represents the only source of drinking water for the population. Groundwaters are stored in superposed aquifers, most of them confined, generally having good hydrogeological properties. Water quality complies with the standards for drinking water and that is why groundwaters are used as such for domestic consumption. The problem is that in the past years, population increase has put more pressure on this resource and consequently water table sank. The growing depletion of groundwaters has brought about thirst, famine, poverty and despair, sad realities that local authorities are striving to control. Given this necessity the present study aims at making several proposals of what could be done on a short and middle term in order to increase the water supplies of the region and thus alleviate the people??s suffering.  相似文献   

Tsunami risk for Western Canada and numerical modelling of the Cascadia fault tsunami     

Jinsong Xie  Ioan Nistor  Tad Murty 《Natural Hazards》2012,60(1):149-159

The paper deals with the analysis of tsunami risks for Western Canada and the numerical modelling of a potential tsunami which could affect the region and generate significant damage to the western Canadian coastline. Following a review of the seismic risk and historical tsunamis which occurred along the western Canadian coastline, the authors concluded that this region is highly vulnerable should a major tsunami occur. Consequently, the authors conducted a study on the numerical modelling of a possible tsunami generated by movement along the Cascadia fault, which is located offshore British Columbia. The results of the model outline the significance and extent of the coastal flooding risk associated with such a rare, but destructive phenomenon. The potential for inundation of the low-lying areas around the coastline of Vancouver Island and in and around the City of Vancouver was found to be high. A number of recommendations and conclusions focusing on the results of the numerical simulation are included.  相似文献   

Holocene vegetation history in Romanian Subcarpathians     

Ioan Tantau  Maurice Reille  Jacques-Louis de Beaulieu  Sorina Farcas  Simon Brewer 《Quaternary Research》2009,72(2):164-173

Pollen analysis from a peat core 7.0 m in length, taken from a bog near Bisoca, in a mid-altitude area of the Buzăului Subcarpathian mountains, is used to reconstruct the postglacial vegetation history of the region. The vegetation record, which is supported by twelve ¹⁴C dates, starts at the end of the Late Glacial period. At the Late Glacial/Holocene transition, open vegetation was replaced by forest, suggesting a fast response to climatic warming. The Holocene began with the expansion of Betula, Pinus and Ulmus, followed, after 11,000 cal yr BP, by Fraxinus, Quercus, Tilia and Picea. The rapid expansion of these taxa may be due to their existence in the area during the Late Glacial period. At ca. 9200 cal yr BP, Corylus expanded, reaching a maximum after 7600 cal yr BP. The establishment of Carpinus occurred at ca. 7200 cal yr BP, with a maximum at ca. 5700 cal yr BP. Fagus pollen is regularly recorded after 7800 cal yr BP and became dominant at ca. 2000 cal yr BP. The first indications of human activities appear around 3800 cal yr BP.  相似文献   

Magmatic and tectonic history of Jurassic ophiolites and associated granitoids from the South Apuseni Mountains (Romania)     

Daniela Gallhofer  Albrecht von Quadt  Stefan M. Schmid  Marcel Guillong  Irena Peytcheva  Ioan Seghedi 《Swiss Journal of Geoscience》2017,110(2):699-719

The Jurassic ophiolites in the South Apuseni Mountains represent remnants of the Neotethys Ocean and belong to the East Vardar ophiolites that contain ophiolite fragments as well as granitoids and volcanics with island-arc affinity. New U–Pb zircon ages, and Sr and Nd isotope ratios give insights into their tectono-magmatic history. The ophiolite lithologies show tholeiitic MOR-type affinities, but are occasionally slightly enriched in Th and U, and depleted in Nb, which indicates that they probably formed in a marginal or back-arc basin. These ophiolites are associated with calc-alkaline granitoids and volcanics, which show trace element signatures characteristic for subduction-enrichment (high LILE, low HFSE). Low ⁸⁷Sr/⁸⁶Sr ratios (0.703836–0.704550) and high ¹⁴³Nd/¹⁴⁴Nd ratios (0.512599–0.512616) of the calc-alkaline series overlap with the ratios measured in the ophiolitic rocks (0.703863–0.704303 and 0.512496–0.512673), and hence show no contamination with continental crust. This excludes a collisional to post-collisional origin of the granitoids and is consistent with the previously proposed intra-oceanic island arc setting. The new U–Pb ages of the ophiolite lithologies (158.9–155.9 Ma, Oxfordian to Early Kimmeridgian) and granitoids (158.6–152.9 Ma, latest Oxfordian to Late Kimmeridgian) indicate that the two distinct magmatic series evolved within a narrow time range. It is proposed that the ophiolites and island arc granitoids formed above a long-lived NE-dipping subduction zone. A sudden flip in subduction polarity led to collision between island arc and continental margin, immediately followed by obduction of the ophiolites and granitoids on top of the continental margin of the Dacia Mega-Unit. Since the granitoids lack crustal input, they must have intruded the Apuseni ophiolites before both magmatic sequences were obducted onto the continental margin. The age of the youngest granitoid (~153 Ma, Late Kimmeridgian) yields an estimate for the maximum age of emplacement of the South Apuseni ophiolites and associated granitoids onto the Dacia Mega-Unit.  相似文献