Найдено 16
Ничего не найдено
Correction to: Geoenvironmental Changes in the Cordillera Blanca, Peru
Vilímek V., Mark B., Emmer A.
Correction to: The Nature of Geomorphological Hazards in the Nepal Himalaya
Kalvoda J., Novotná E.
Conclusions: The Dynamics and Complexity of Geomorphological Hazards in the Nepal Himalaya
Kalvoda J., Novotná E.
The final chapter of the book describes the specifics of geomorphological hazards in the Nepal HimalayaNepal Himalaya-Nepal Himalayas. The destructive effects of the concentration of individual types of natural hazards of orogenetic and climate-morphogenetic origin in varied spatial and temporal scales are emphasized. The main conceptual and methodological challenges in the complex research of geomorphological hazards and risks in the extreme environments of the Nepal HimalayaNepal Himalaya-Nepal Himalayas are presented. In these contexts, physical geography and geomorphology are evaluated as promisingly developing fields of natural science that, together with other EarthEarth sciences, can contribute to a substantial reduction of serious social losses caused by natural hazards and disasters in the high mountain regions of Asia.
Treatise on Remarkable Morphogenesis of the Nepal Himalaya
Kalvoda J., Hubbard M.
Research into the dynamics of landform evolution in the Nepal HimalayaNepal Himalaya-Nepal Himalayas is intended to provide knowledge of the long-term integrity of climate-driven morphogenetic and tectonic processes as an essential phenomenon of active collisional orogeny. Landform patterns of the Himalaya are the result of orogenetic processes, as well as the denudation and erosional efficiency under variable palaeoclimatic conditions during the late Cenozoic. The observed landform changes in the Nepal HimalayaNepal Himalaya-Nepal Himalayas indicate the high intensity of climate-driven morphogenetic processes, especially very effective erosion, and transport of weathered material by a combination of diverse exogenic factors, integrated with active orogenetic processes. The dynamic evolution of landforms in the Nepal HimalayaNepal Himalaya-Nepal Himalayas is also essential evidence of the present-day severe natural hazards.
Geomorphic Hazards in the Makalu Barun Area of the East Nepal Himalaya
Kalvoda J., Emmer A.
The paper provides evidence of dynamic landform evolution in theMakalu-Makalu Barun area, Makalu base camp Makalu Barun area which indicates extreme geomorphic hazards and risks. Dominant geomorphic processes and typical landforms of vertical morphoclimatic zones are described, highlighting the role of mass wasting processes and far-reaching process chains acting across these zones of the East Nepal HimalayaEast Nepal Himalaya-East Nepal Himalayas. The main features of recent geomorphic processes in the Makalu Barun area are: (1) in the extreme glacial zone: extensive weathering of rocks in a very cold and semi-arid environment, frequent avalanches and rockfalls, wind erosion, stagnation of volume of ice and snow masses; (2) in the glacial zone: retreat of glaciers and substantial decrease in their volumes, spreading of the periglacial area to the detriment of lower levels of glacial zone; (3) in the periglacial zone: intensive regelation processes and fluvial erosion of rocks and Quaternary sediments, frequent slope movements, especially rockfalls and landslides; (4) in the seasonally cold/warm humid area: its expansion to warming periglacial zone, frequent slope movements of various types and magnitude and intensive fluvial erosion. While extreme glacial zone is stagnant, remaining three zones have been experiencing location changes and substantial enlargement associated with changing climate, glacier extent and permafrost distribution.
The Role of Natural Hazards and Socio-Cultural Factors in Shaping the History of Settlement Locations in the Limi Valley, North-West Nepal
Kropáček J., Hovden A.
The Limi Valley is a high mountain area adjacent to the Main Himalayan Ridge in the north-west of NepalNépal. The valley’s rugged terrain and harsh climate induce processes that represent multiple hazards for the local Tibetan speaking community. We investigate the complex interrelationship between natural hazards and socio-economic and cultural driving factors for relocation and abandonment of settlements in this high-altitude community. We document past natural disasters and present hazards using historical aerial photographs, satellite imagery, and a detailed Digital Elevation Model derived using Structure from Motion approach. These data were supplemented with accounts from village archives in Tibetan language, interviews with local inhabitants and participant observation. We observed how the various categories of natural hazards are dealt with and re-evaluated against other risks and dangers. We have documented the abandonment and relocations of settlements and monasteries in the Limi ValleyLimi Valley. Change in water availability, outbreaks of epidemics, as well as religious concerns were listed among the likely driving factors for past relocations. The present settlement locations are less safe with respect to natural hazards and discusses how local risk perception and adaptation strategies are shaped by multiple, partly competing concerns, of which natural hazards constitute only one.
Diverse Perception of Natural Hazards and Disasters by the Inhabitants of the Himalaya
Kalvoda J., Novotná E.
In the study, the main features of perception of natural hazards from the viewpoint of the inhabitants of the Himalaya are outlined. The spiritual significance of people’s attitude to the mountains expressed in ancient mythology is emphasized. The pioneering and recent periods of exploration of the natural environment of the Himalaya are briefly described, and current trends in the recognition of natural hazards and risks, including active protection of the population, are indicated. Special attention is paid to extreme natural hazards and risks on high Himalayan ridges and rock faces. It is necessary to search optimal procedures for protecting people from catastrophic events and the consequences of natural hazards. The main reasons are both ongoing global climate changes and raising human activities in the diverse and dynamic environment of the Himalaya.
Development of the Map Representation of the Nepal Himalaya Up to the End of Nineteenth Century
Novotná E.
Historical cartography is an important source of data on the early periods of exploration of the Himalayan natural environment. The chapter provides an overview of the development of Himalayan mapping. Twenty old maps have been analysed. The Greeks plotted the Himalaya as a barrier of mountains designated as Imaus monsImaus mons or Emodi montesEmodi montes. Medieval circular maps present a string or waves of mountains. Greek names were adopted, among others, by the Dutch, and the cartographer A. Ortelius added the name DalangerDalanger–Dalanguer, Dalanguer mons. An entirely new image of the high mountains was presented by J. B. d’Anville in 1733 on his map of TibetTibet-Tibet Autonomous Region. His work was an inspiration for other representatives of French, German and Austrian cartography. In 1788, J. Rennell marked the mountains as HimmalehHimma leh–Himmaleh, Himma-leh. In 1802, geodetic triangulation of the Indian PeninsulaIndian Peninsula began, and the mountain peaks were measured remotely across the borders. Since the nineteenth century, the Himalaya has been depicted by hachures. Special maps of the Himalaya were published in German atlases. In the second half of the nineteenth century, Peak XVPeak XV was namedM Everest Mount EverestMount Everest. Triangulation was completed in 1863 by J. T. Walker. Other cartographic representations to be found in the summary table.
Mass Density Variations of Landforms, Active Orogeny and Erosion in the Nepal Himalaya Derived from the Earth Gravity Model EIGEN 6C4
Kostelecký J., Kalvoda J., Klokočník J., Bezděk A.
Geomorphic processes and events proceeding during the present collisional orogeny between the IndianIndian lithospheric plate and Asian lithospheric platesAsian lithospheric plate reveal itself in various functions of the gravitational potential. We explore gravity imprint of landform patterns and morphogenetic phenomena in the Nepal HimalayaNepal Himalaya-Nepal Himalayas by means of the global gravity model of the Earth EIGEN 6C4. SelectedEarth groups of gravity aspects are computed from the EIGEN 6C4 through the harmonic potential coefficients over the Himalayan regions. The comparison of geological, geomorphic and gravity data concerning near-surface part of the Earth crust enable the determination of space distribution of a conspicuous evidence of active orogenetic processes, strong erosion of rock assemblages, mass movements and related natural hazards in the Nepal HimalayaNepal Himalaya-Nepal Himalayas. The graphically expressed values of the selected gravity aspects computed from the EIGEN 6C4 show remarkable Himalayan phenomena related to (1) mass distribution of large-scale high mountain landforms, deep-side glacial and fluvial erosion and principal morphotectonic zones recorded by means of second-order derivatives of the gravitational potential; (2) main areas with extensive slope disturbances, giant mass movements and active exfoliation processes determined through virtual deformations of the ellipse of deformation; and (3) variations in the density of rock massifs—detected by arrangements of gravity strike angles—which are caused by their deformations and morphostructural discontinuities created by diverse lithospheric stress fields operating during the collisional orogeny of the Himalaya.
An Actual Biogeographical Hazard of the Expansion of Small Mammals and Their Parasites Linked with Climate Changes in the East Nepal Himalaya
Daniel M., Kalvoda J.
The results of zoological and parasitological research in the MakaluMakalu-Makalu Barun area, Makalu base camp Barun region are presented. These findings are compared with the landform evolution during the Quaternary. The complex interpretation made it possible to determine the expansion and migration of small terrestrial mammals in correlation with the orogenetic uplift and changes in the extent of mountain glaciation since the Upper Pleistocene. Biogeographical hazards and risks associated with the rapid expansion of the periglacial climate-morphogenetic zone and the increased human impact in the High HimalayaHigh Himalaya are emphasized.
Introduction
Kalvoda J., Emmer A., Steklá T.
Specialized topics of this book on geomorphological hazards and related natural phenomena are introduced by a brief description of the diverse environment of the Nepal HimalayaNepal Himalaya-Nepal Himalayas. The physical-geographical features of NepalNépal are explained through its geological and orographical arrangement and an overview of climatic conditions and hydrological as well as biogeographical phenomena adapted to it. Furthermore, the methodological aspects of the research of the high mountain environment are discussed in relation to the progress in the knowledge of geomorphological hazards in the Nepal HimalayaNepal Himalaya-Nepal Himalayas.
Climate-Morphogenetic and Morphodynamic Zones of the Western Cordillera in Peru
Vilímek V.
The description of climate-morphogenetic and morphodynamic zonation aspires to a complex characterization and bridges the gap between climatic and geomorphic settings. Ongoing and future climate-change effects are prominent for landscape evolution as well as for natural hazard processes. The profile from the coastal zone and foothills across the Cordillera Negra, Santa River valley (Callejón de Huaylas) and the Cordillera Blanca represents a large variety of vertical zones with various environments. An atypical mezzo or microclimate may be found in narrow canyon-like valleys. With respect to the above-mentioned climatic characteristics (preconditions), subsequent regionalization may be performed according to Peñaherrera (Gran Geografía del Perú, vol I. Barcelona, 1986). The coastal zone including the foothills climbs to 1000 m a.s.l., while most of the area is covered by mountainous zones (local names: Yunga, Quechua, Suni, Puna, and Janca). The regionalization is based on similar conditions in terms of elevation, temperature, precipitation (including rainfall, snow, mist etc.), air pressure, and vegetation, and is usually related to specific morphological units.
Stability of Moraine and Rock Slopes at Glacial Lakes—Two Case Studies in the Cordillera Blanca
Novotný J., Klimeš J.
Two presented cases of slope-specific stability assessment illustrate an approach of low-impact investigation techniques, which at the same time allow obtaining necessary data for reliable and realistic slope stability calculations. The applied methods combine field geomorphological, structural and engineering geological investigations with basic laboratory rock and soil tests to constrain the strength properties of the soil, rock discontinuities and rock mass forming landslide material and determining its initiation. Careful observations of the slope’s natural conditions served as input data and along with available historical information about sliding frequencies were used to validate the results of the slope stability calculations. For the investigated cases, they show that glacier retreat and thinning were necessary, but not sufficient conditions for landslide initiation in both, a moraine and a rock slope. Other factors need to contribute to low slope stability and material strength to allow failure initiation. These are water saturation of both, soils and rocks within a slope, seismicity, favorable slope dips and structural conditions, and long-term rock strength deterioration, which is probably one of the factors resulting in delayed rock slope response to deglaciation. At higher altitudes, climate-induced permafrost degradation has the potential significantly contribute to long-term slope destabilization.
Geomorphological Setting of the Cordillera Blanca
Vilímek V.
Surface processes and landforms in the Cordillera Blanca has been studied by several research teams over the years, especially because of the various types of natural hazards and glaciers that are found in the region. Pronounced neotectonic activity has influenced several geomorphological processes, such as fluvial erosion and slope movements. The landscape is usually highly dissected by processes influenced by endogenous activity (e.g., tectonic activity) as well as by exogenous processes (e.g., erosion and slope movements) whose intensity varies in space and time. Also, the large relief differences support the intensity of ongoing processes. Most dynamic processes are usually triggered by earthquakes or intensive precipitations (during the rainy season or El Niño period) and different processes can influence each other in terms of triggers. It is reasonable to expect that ongoing climate changes as well as deglaciation will influence future dynamic morphological processes.
How People Feel Endangered by Natural Hazards: Interpretation of Questionnaires in the Callejón de Huaylas
Vilímek V., Šifta J.
The objective of this study was to find out the opinion of a selected population at risk in the Cordillera Blanca. We distributed questionnaires among the local population, which revealed their perception of several natural hazards. These results were compared with known hazards both from literature and our own experience from fieldwork. An approach combining physical and human geography together with statistical methods was used to identify the most dangerous threats, namely global warming, and pollution. The social aspect of the investigation suggests that the population at risk does not trust the local authorities and obtains most of its information from television.
Landslides in the Cordillera Blanca
Klimeš J.
Landslides are essential for the landscape character in Cordillera Blanca Mts. where they also represent natural hazard with potentially catastrophic effects on society. This is why the traditional knowledge of the mountain inhabitants contains explanations of their origin as well as measures mitigating their negative impacts and this information proved to be useful for scientific research and in landslide risk reduction efforts. Landslide spatial and temporal distribution as well as scientific knowledge about them is uneven. Most of the documented landslides of different types were mapped in Mesozoic sediments and metamorphic rocks, while granites are less susceptible with rock falls as the prevailing landslide type. Cordillera Blanca landslides are triggered by earthquakes capable of initiating thousands of landslides ranging from single boulder falls to extremely voluminous and fast ice/rock avalanches, which claimed about 6000 casualties during the May 31st 1970 earthquake. Prolonged and intensive precipitations during the annual rainy seasons along with glacier melt water are responsible for increased groundwater levels triggering rock or debris slides and flows. The number of reported landslides whose origin is linked to permafrost degradation is still rather small, but their future frequency is expected to significantly increase due to observed and predicted global warming. They often impact recently enlarging and newly forming glacial lakes and initiate chains of hazardous processes. They possibly result in far-reaching floods which attract a lot of scientific attention. If future research is to gather the necessary information to effectively reduce landslide risk, it must focus on previously neglected (e.g., landslides and debris flows in the piedmont region) or under-researched (e.g., mountain permafrost conditions) topics searching for ways to include traditional knowledge in the investigations and results application.
