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Abstract A necessary stage in calculations for prediction purposes is the study of the tsunami recurrence function which yields mean recurrence of tsunami with maximum wave height not greater than a specified level h. The major problem in using these functions for prediction purposes is the fact that a well‐grounded approximation of empirical data on wave heights is difficult to obtain, because the mathematical model for prediction is an extrapolation of this function for tsunami heights whose recurrence remains uncertain. We shall show that the natural relation of observable tsunamis statistics to extremum statistics leads to the discovery of at least two and possibly three temporal scale intervals with different tsunami modes. It has also been clarified that for the 10 years < T < 103 years range of time periods, which is the most important one for tsunami wave height prediction purposes, the tsunami recurrence is described by two parameters: frequency A of occurrence of large tsunamis and coefficient k of wave ampliflcation near the shore. As an example, a diagram of tsunami hazard zoning of the eastern Honshu coast has been plotted. 相似文献
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P. A. Gillespie 《新西兰海洋与淡水研究杂志》2013,47(1):91-107
A comparative study of the heterotrophic potentials of ten New Zealand lakes was carried out. Two sampling periods were chosen, one during late August and early September 1972 (late winter, minimal thermal stratification) and another during February 1973 (mid summer, strong thermal stratification in all but two lakes). A wide range of heterotrophic potentials occurred which enabled the lakes to be placed in the following basic groups according to descending trophic levels: Group I: Rotowhero (thermal, acid lake) >Rotorua>Okaro Group II: Rotokakahi> Tikitapu >Okareka Group III: Rotoma = Rotoroa (S.I.) = Rotoiti (S.I.) = Okataina Maximum values for heterotrophic potential (Vm a x ) in micrograms of glucose per litre per hour were: Maximum heterotrophic activities were found within the metalimnion, except in Lakes Tikitapu and Rotokakahi, where maximum activities occurred within the hypolimnion. 相似文献
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A. Eslami M. Alimirzaei E. Aflaki H. Molaabasi 《Marine Georesources & Geotechnology》2017,35(1):62-79
For the past four decades, the CPT has played a key role in onshore and offshore soil investigations. One of the main applications of cone penetration test (CPT) is the soil behavioral classification. Most of the developed methods for soil identification using CPT and CPTu (piezocone) data are well categorized for common soils, such as clays, silts, and sands. Soils with low resistance or more compressibility generally involve problems in geotechnical engineering practice and construction projects. Consequently, these unusual deposits require further evaluation and more detailed data. Five major groups of problematic soils including: liquefiable, sensitive, peaty, collapsible, and expansive soils have been considered in this study. One hundred and forty CPT and CPTu test records were collected from fifteen countries. Sixty-one of the records are related to difficult soils. A brief comparison is performed for currently used soil behavioral classification charts, such as by Campanella et al. (1985), Robertson (1990), Jefferies and Davies (1991) and Eslami and Fellenius (1997). Analysis based on CPT data indicates that a few commonly used charts recognize relatively well problematic deposits. However, further studies are needed to increase the accuracy and capability of methods. Existing charts have some problems due to the limitations of the nature of rectangular charts based on two axes. A new format of classification chart, i.e., triangular form containing cone tip resistance (qc), sleeve friction (fs), and pore pressure (u2) is proposed for soil identification which can be realized in practice. The proposed chart with more accuracy and less scattering of data than the previous charts is able to identify soil types particularly for deltaic soils. 相似文献