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Deposits from as many as 50 large tsunamis during the last 7000 years are preserved on the Pacific coast of the Kamchatka Peninsula near the mouth of the Zhupanova River, southern Kronotskiy Bay. These deposits are dated and correlated using Holocene marker tephra layers. The combined, preserved record of tsunami deposits and of numerous marker tephras on Kamchatka offers an unprecedented opportunity to study tsunami frequency. For example, from the stratigraphy along southern Kronotskiy Bay, we estimate frequency of large tsunamis (>5 m runup). In the last 3000 years, the minimum frequency is about one large tsunami per 100 years, and the maximum about one large tsunami per 30 years; the latter frequency occurred from about 0 to 1000 A.D. This time interval corresponds to a period of increased seismicity and volcanic activity that appears to be recorded in many places on the Kamchatka Peninsula.  相似文献   
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A total of twenty-three water samples were collected in winter 2013 to assess groundwater quality in the Oued Rmel aquifer in the Zaghouan governate in Tunisia. These samples were subject to in-field measurements of some physico-chemical parameters (temperature, pH, and salinity), and laboratory analysis of major elements. Several parameters were used to assess the quality of water destined for irrigation, including electrical conductivity (EC) and sodium adsorption ratio (SAR). As part of this work, GIS was used to study spatial distributions of SAR, EC, residual sodium carbonate, sodium percentage (%Na), Doneen’s permeability index, Kelly’s ratio, and magnesium hazard and, therefore, evaluated the water quality of Oued Rmel (good, fair, or poor) regarding irrigation. The major ions most abundantly found in the waters of Oued Rmel were in the following order: Na+?>?Ca2+?>?Mg2+?>?K+ and Cl??>?SO42??>?HCO3. 56% of water samples from the Oued Rmel aquifer showed a low alkalinization risk, where SAR was lower than 10, 39% have a medium soil destabilization risks (10?<?SAR?<?18), and just 5% indicated high alkalinity hazards (SAR?>?26). Samples of water intended for irrigation showed a medium to high sodicity and alkalinization risk. It is expected that output may help in assessing the impacts of water quality of the Oued Rmel aquifer used for irrigation.  相似文献   
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We performed simple numerical simulations to investigate the capture of dwarf galaxies by larger ones in the environment of a cluster of galaxies. The number of captures is small compared to the total number of dwarfs, but it is significant because these galaxies are the most abundant members of galaxy clusters. Our models show that, having a more massive central galaxy or a less massive background halo in the cluster, increases the number of captures. A high proportion of the orbits of the captured dwarfs are very eccentric. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
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The study area is located in the western Hoggar Shield (southern Algeria). It includes the In Ouzzal terrane, which consists of Archaean metamorphic rocks. By contrast to other rocks of the Hoggar Shield, the In Ouzzal terrane represents an exception of being neither deformed nor metamorphosed during the Pan-African event, remaining as a rigid block since 2 Ga. Although, previous geophysical works in the area include an airborne magnetometer and gamma-ray spectrometric survey as well as ground gravity and magnetotelluric survey structurally, the study area has not been very well understood. In this paper, we present the interpretation results of the airborne magnetic data by using the 3D Euler deconvolution and the improved Tilt-angle methods. These results reveal the existing of fault systems (FS) occurring within the center of the study area and along the latitude of 22°; the results also suggested that the deepest fault system is oriented NE–SW and is represented by parallel major faults splitting the In Ouzzal terrane into two different parts: northern and southern. The northern part moved northwards, whereas the southern part moved southwards colliding with the Iforas unit. The interpretation confirms that the In Ouzzal terrane and the surrounding Pan-African structures are bound two by two sub-vertical lithospheric faults with the existence of dextral and sinistral faults in the west and east of the terrane, respectively.  相似文献   
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