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FOUR IMPORTANT NATURAL HAZARDS FROM ROMANIA MARINESCU Mihai 1, STANCIU Christian 2, MARINESCU Georgeta 3 1 University of Bucharest, Faculty of Geology and Geophysics, Mineral Resource Management and Center, 6 Str. Traian Vuia Street, [email protected] 2 INCD GeoEcoMar, 23-25 Dimitrie Onciul Street, Bucharest, [email protected] 3 High school “George Calinescu”, Bucharest Environment 1. Hazards In Romania In time, all subgroups of natural hazards (cosmic, geological, hydro-meteorological and biological) have been recorded in Romania. Types of natural hazard are very numerous (over 50). Sometimes, some of them have acted in periods of maximum vulnerability of the society and of the environment, causing real disasters. The most numerous ones have been the hydro-meteorological and perhaps the biological subgroups, followed by geological ones and, finally, with negligible frequency and consequences, by the cosmic hazards. An attempt to classify the natural hazard group known in Romania is presented in Table 1, detailed on subgroups, and subcategories. Table 1. Natural hazards which affected or which may affect Romania. SUBGROUPS 1.Cosmic (astrophysics) hazards 2.Geological hazards CATEGORIES Cosmic corps fall Cosmic corps clink Cosmic corps blast Hazards produced by internal factors of the Earth Hazards produced by external factors of the Earth SUBCATEGORIES Movement of released soils, roks and sediments masses Movement of snow and ice masses 3.Hydrometeorologycal hazards Movement of air masses Movement of water masses Electrical discharges Frost phenomena of water Movement of fresh water Movement of sea water Movement of fresh and sea waters Frost water in air Frost water on rivers Moisture deficiency Excessive temperatures Natural arsons 4.Biological hazards Epidemics Epidemics caused by bacteria Epidemics caused by viruses Epidemics caused by rickettsii Epizootics Epidemics caused by toxins Epidemics caused by unknown causes For people and animals For animals Invasions of insects TIPES Meteors fall Comets, asteroids, stars clink Gamma radiations Earthquakes Volcanic eruptions Landslides Falls, rolling land-slide or crumblingof rocks Avalanches Storms, Blizzards, Tornados Water flow, Torrents, Floods Storm waves Floods on the Danube Lightnings, Thunders Fogs, Hails Ice floes, Ice bridges Droughts Very high temperatures Very low temperatures Arsons of forest Arsons of land Plague, Cholera, Anthrax, Leprosy, Brucellosis Smallpox, Encephalitis, Meningitis, Malaria, Influenza, West Nile, SARS, HIV Foot and mouth disease, Typhus Botulism Balkan endemic nephropathy (NEB) Cholera, Plague, Brucellosis, SARS, Foot and mouth disease, Glanders, Ornitoza-psittacosis Pig pesta Caterpillars invasion Grasshoppers invasion Various natural hazards (cosmic, geological, atmospherically, hydrological and biological) have been recorded in Romania. Nevertheless, four from the most important hazards, regarding the 113 number of dead or affected persons, or economic damages, are the earthquakes, floods, droughts and excessive temperatures. 2. Earthquakes In connection with earthquakes felt in Romania, there are several main epicenter areas (Vrancea, Fagaras, Banat, and Black Sea), some minor areas and regions in the neighborhood countries. The most important, by energy and frequency effects, are Vrancea earthquakes. The seismic activity is mostly located at depths of 70-160 km (intermediate depth), in an epicenter area of approximately 2000 km2 There is also some minor crustal activity with depths down to 40 km, extending on an area up to 7000 km2. Inside the Carpathian arc, they felt relatively weak. Usually, intermediate depth earthquakes of moderate magnitude are single shock ones, but the strong events are accompanied by numerous replicas. The November, 10th, 1940 event has a magnitude of 7.4. Fagaras earthquakes are polikinetic ones (multiple shocks). They have a long duration and moderate intensity, reaching up to VII (Lazarescu, 1980). The hypocenter depth is crustal one (1020 km), they being connected to several major fault systems separating Transylvania from the Fagaras Mountains. Banat earthquakes (Danubian ones) are generated along the fractures of the basement, being located between the Varset Massif (in Serbia), Vinga and Moldova Noua. They are polikinetic events (multiple shocks) with normal depth. They have reached the intensity up to VII and their macro seismic area is narrow. The Pontic earthquakes are located in the proximity of the Black Sea coast, usually between Mangalia and Sabla area (Bulgaria). They occur frequently (2-3 per year), are polikinetic ones and have a low energy. Their occurrence is at the intersections of several important faults, both on land and on the sea self. Almost twice the millennium such destructive earthquakes have been recorded on the Bulgarian territory. The secondary epicenter areas are related to faults of the basement, occurring at depths of 10-20 km. They have a local nature. Most active are those connected with parallel fractures limiting the East-European Platform, after then it goes down in steps to Carpathian orogen (Botosani Dorohoi and Avramesti Barlad); the ones related to the extension towards North and East, at a basement level, of several faults of North Dobrudja orogen (Tecuci-Tudor Vladimirescu, Marasesti-Focsani-Namoloasa, Tulcea-Isaccea-Galati); also the earthquakes located in the area of faults placed in the basement of the central part of Transylvania Depression (Tarnavelor area). On the Romanian territory, earthquakes having the epicentral area in neighboring countries (Bulgaria, Serbia) or in Greece or Turkey are also recorded. The Bulgarian ones are placed on the trench structure existing along Marita river, or are linked to the fault system limiting Rhodopi Mountains. Earthquakes in Serbia are associated to the trench existing along Morava valley. 3. Floods Floods are among the most popular in the area and most common hazard that occur in Romania, sometimes having great economic and social consequences. Floods usually take place over the course of internal rivers and of the Danube. In these cases a small river having usually small debits, increase dramatically the amount of transported water, producing on overflow and filling the major riverbed. Annual occurrence is around 10-15 floods, with greater frequency at medium altitudes (in the mountains and Sub-Carpathians) and lower frequency towards the plain. Catastrophic floods are produced every 50 -100 years because of torrential rains combined with sudden snow melting. They are most frequently occurring in the western part of the country. Spring held regularly floods by melting snow, above which the overlap of spring rains. At the beginning of summer, they are wide spread in the country, being due to heavy rain. Autumn are rarer, due to rainfall during October-November and having a higher frequency in Banat and Oltenia. It is estimated that the maximum exposed flooding in our country is about 3.5 million ha, representing 15% of the country. In 2005, damage to the national economy has exceeded 1.7 billion dollars. For the floods from 2010, the damage was not yet calculated. 114 4. Droughts Droughts occur in May and have drastic effects in the areas of plain, non-irrigated land. In Baragan and Dobrogea, the average duration of dry intervals is over 20 days, in the Romanian Plain, in the Plateau of Moldavia is 15-19 days, and for the rest of the country is about 17 days. Although droughts can register throughout all the year, the most numerous are produced in late summer and early autumn. The territories, which are exposed to drought, are in the Southeast of the country (Baragan, Dobrogea, Moldova Southern Plateau). Throughout the whole country, drought in the summer of 2000, extended until the winter of 2001, has been the strongest of the past 100 years. It affected over 3.7 million hectares of land. The river has fallen considerably, the Danube has been the lowest level from 1840 onwards (when it started to be monitored its level). It was affected also the national energy system due to a low level in lakes. Damage to the national economy has exceeded 3 billion dollars. 5. Excessive Temperatures Excessive temperatures which is not usual in the area of Romania, with temperate climate, those are either too high during summer or in winter too low. They persist for several days in a row. Temperatures too low or too high are not proper to human bodies when persist a longer period. Very high temperatures accompanied by excessive moisture, are usually caused by warm air masses, coming from Africa across the Mediterranean Sea. They may cause, especially in urban areas, a number of deaths among young children, and aged, sick and disabled people. When the heat wave persists for a longer period, drought can occur, triggering fires (in the woods or areas with dry vegetation). Alternatively, they are activated epidemic outbreaks of epizootic diseases, putting in danger the agricultural-forest fund. References: Balteanu, D., Alexe, R., 2001. Natural and anthropogenic hazards. Corint publishing house Grecu, F., 2006. Natural hazards and risk. Universitara publishing house. Bucharest. Lazarescu, V., 1980. Physical geology. Technical publishing house. Bucharest. Marinescu, M., 2006. Natural disasters. International University Press. Bucharest Marinescu, M. et al., 2007.Natural and technological hazards that can produce disasters in Romania. Evaluating the risks and measures of preventing and limiting the impact on the society and the environment. Partnerships in priority area.1st – 4th stages. CNMP archives. Bucharest. 115