Suchergebnisse

Abstract. A tsunami generated by large-volume landslide can propagate across the ocean and flood communities around the basin. The evolution of landslide-generated tsunamis is affected by the effects of frequency dispersion and involves processes of different temporal and spacial scales. In this paper, we develop a numerical approach employing the weakly nonlinear and fully nonlinear Boussinesq-type theories and nested computational grids. The propagation in a large domain is simulated with the weakly nonlinear model in a geographical reference frame. The nearshore wave evolution and runup are computed with the fully nonlinear model. Nested grids are employed to zoom simulations from larger to smaller domains at successively increasing resolutions. The models and the nesting scheme are validated for theoretical analysis, laboratory experiments and a historical tsunami event. By applying this approach, we also investigate the potential tsunami impact on the US east coast due to the possible landslide on La Palma Island. The scenario employed in this study represents an event of extremely low probability.

The article analyzes the Russian citizens' perceptions of BRICS countries. The authors focus on the cognitive, emotional, behavioral, and symbolic aspects characterizing BRICS countries in political consciousness of the Russians as well as common stereotypes, intentions, and associations. Since the Russian Federation has political and economic interests in cooperation with the BRICS countries, it is important to study representations of Brazil, India, China and South Africa in Russian consciousness and identify the possibilities of their transformation. Proceeding from the results of qualitative politico-sociological (a series of focused interviews) and politico-psychological (projective tests) studies held in 2016-2018 the authors conclude that the emotional component prevails in the structure of Russian citizens' perception about of Brazil, India, China and South Africa. The image of China appears to be the most complicated and multidimensional, with the key elements being the "thousand-year history", the "great culture" and the recognition of the geopolitical power of this state. The images of India and Brazil among the Russians have a significantly more amorphous character, but at the same time hold a moderately positive emotional connotation. The image of South Africa is the most fragmented, devoid of stable emotional valence and bright associations. It is remarkable that the perception of the BRICS countries by the majority of respondents is primarily influenced by implicit factors which manifest in appeal to stereotypes and associations (India – cinema, Brazil – football, etc.). Dynamic factors, determined by political agenda, play a minor role forming the images of the BRICS countries. A noticeable feature of their representation among the Russians is the blurring of the "image of due" and "image of the future", as well as the minimal role of the political component (with exception of China). Therefore, it is necessary to change the information policy for the countries studied. In order to enhance the understanding of significance and relevance of cooperation with the BRICS states among the Russian citizens, it seems to be necessary 1) to build a positive image of political relations with them; 2) to cement an image of a "partner" and an "ally" in mass media, both on a rational and an unconscious level of political perception.

Abstract. Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude is much smaller than it is closer to shore. An effective early warning system, however, must be able to observe an impending tsunami threat far away from the shore in order to provide the necessary lead-time for coastal inhabitants to find safety. Given the expansiveness of the ocean, sensors capable of detecting the tsunami must also have very broad areal coverage. The 2004 Sumatra-Andaman tsunami was definitively detected in the open ocean from both sea surface height and sea surface roughness measurements provided by satellite altimeters. This tsunami, however, was exceptionally strong and questions remain about the ability to use such measurements for the detection of weaker tsunamis. Here we study the 2010 Chilean tsunami and demonstrate the ability to detect the tsunami in the open ocean. Specifically, we analyze the utility of filtering in extracting the tsunami signal from sea surface height measurements, and, through the use of statistical analyses of satellite altimeter observations, we demonstrate that the 2010 Chilean tsunami induced distinct and detectable changes in sea surface roughness. While satellite altimeters do not provide the temporal and spatial coverage necessary to form the basis of an effective early warning system, tsunami-induced changes in sea surface roughness can be detected using orbiting microwave radars and radiometers, which have a broad surface coverage across the satellite ground track.