排序方式： 共有26条查询结果，搜索用时 0 毫秒
21.
Kirui Pius Oiro Samson Waithaka Hunja Odera Patroba Riedel Björn Gerke Markus 《Natural Hazards》2022,111(1):213-237
Natural Hazards - Himalayan mountains are one of the most seismo-tectonically active zones on the surface of the earth. Recurring moderate and high magnitude earthquakes are not uncommon in this... 相似文献
22.
To identify the key features of the free-field response for inplane motion, a vast parametric study is performed, varying the location of the control point, the nature of the wave pattern and the site properties. Harmonic excitation for a site consisting of a layer on bedrock is investigated. The nature of the wave pattern producing the site response is classified with respect to the apparent velocity of the motion propagating horizontally across the site. When the control point is selected at the outcrop of the bedrock, the amplification of the motion to the free surface of the site depends on the angle of incidence of the incoming wave in the bedrock. The amplification of the vertical motion for incident P-waves hardly depends (with a tendency of being somewhat larger compared to vertical incidence) on the angle of incidence in the bedrock. The amplification of the horizontal motion for incident SV-waves is affected strongly by the angle of incidence, being larger or smaller than for vertical incidence. Interpreting the two components of the motion at the free surface as arising from a combination of incident P- and SV-waves leads to amplifications within the site (for the horizontal and vertical directions) which do not depend, from a practical point of view, on the angle of incidence and on the prescribed motion up to the fundamental frequency in the horizontal and vertical directions, respectively. The variation of the motion for the first Rayleigh-mode with depth in the two directions bears comparison, in general, with that of vertically incident waves up to the corresponding fundamental frequency. The higher Rayleigh-modes lead to a completely different variation with depth. In contrast to Rayleigh-waves the attenuation of the motion in the horizontal direction for inclined body waves depends on the damping of only the bedrock. Rayleigh-waves thus attenuate more strongly than body waves, especially in the higher-frequency range. Generally, higher Rayleigh-modes attenuate less than the first. 相似文献
23.
24.
Biography
In Memoriam: David le Sueur 相似文献25.
ABSTRACTThe article discusses the range and course of changes in the thermal regime of 14 rivers in Poland over the period 1961–2010. Eleven rivers are located in the Central European Plain, and the others flow in the foothills of the Carpathians Mountains. Statistical analyses take into consideration the results of daily measurements of water temperature carried out at 16 hydrological stations by the Institute of Meteorology and Water Management—National Research Institute. In the first part of the analysed period (1961–1986) water temperature in most rivers declined in relation to its mean value for the entire study period (1961–2010). In 1987 there was a reverse trend: the temperature started rising. The fastest increase in water temperature was recorded in the western part of the study area, and it became slower towards the east. In the southern part of the study area (the foothills) changes of that kind were not observed. The mean yearly temperature of fluvial waters in the Central European Plain showed a positive trend, ranging from 0.17 to 0.27°C (10 years)-1, whereas it did not change in the rivers in the foothills of the Carpathians Mountains. Its fastest rise was recorded in spring, and it reached from 0.08 to 0.43°C (10 years)-1. The increase in water temperature correlated strongly with rising air temperature. The temperature of river waters in the lowlands is believed to be a good indicator of climatic changes.
Editor M.C. Acreman Associate editor T. Okruszko 相似文献
26.
This paper analyses the use of soil horizons for mapping soil degradation intensity and reconstructing chronology of degradation processes. Through “Pedogenetic Baseline Approach”, the catchment was classified into two categories: the erosional and depositional zones. The eroded soils were reconstructed even in those areas where there had been total soil stripping. Profiles of the undegraded soil provided a reference mark (particularly the argillic B horizon of Lixisols). One specific criterion for determining the degree of soil degradation of a given map unit in the erosional zone was based on whether A or B horizons or both had been eroded. Another criterion for classifying the units in the depositional zone was based on relating the quality of the buried soil with the overlying young soil developed from the colluvium/alluvium. Hence, the study underscores the importance of being able to reconstruct soil properties of pre-eroded soil profiles with the view to determining erosion units. This will eventually help in developing appropriate land use and conservation strategies. 相似文献