Elimination of human losses is the main and immediate task in the seismic vulnerability problem.The authors suggest the ways of development of seismic research and discussion of defense problems for reducing of seismi...Elimination of human losses is the main and immediate task in the seismic vulnerability problem.The authors suggest the ways of development of seismic research and discussion of defense problems for reducing of seismic vulnerability. It is the ways of nonlinear seismology region. Unconditionally seism zoning and the theory of catastrophes allow reduce human losses and building destruction. But well-known isoseists are the private case of caustic catastrophe theory or seismo-acoustics, so seism zoning can be amounted to 6 elementary catastrophe forms. It will better help to predict seismic actions. The short-time local prediction of seismic events is general method for strong reducing of human losses. This method takes into account chaotic properties of stress fields and waves and the peculiarities of urban area. It bases on the natural seismo-emission phenomenon and is realized by long-time monitoring, which gives statistically and geographically continuous picture （chart） of seismic noise level inside geologic media. The instruments of this strategy are shock and pressure-proofed seismometers for long-time monitoring and control the state of geological media including underwater shelf areas. The authors think that the active protecting for cities and buildings as the best modem form of people safety consists in stress discharge of geologic media. Ultrasonic wave defense includes and bases on strong interaction between powerful waves from earthquake and ultrasonic wave train. The authors want to point out that the technical objects may be used lbr the investigation of earthquakes induced and some reasons of seismic vulnerability. Also reducing of seismic vulnerability contains as component kinetic acting on volcano at the pre-explosive stage. The interesting and important aspect of defense problem is observation of the inharmonic wave processes in the soil and quasi-constant forces as the nearest seismic analogue of radiation forces in nonlinear acoustics under powerful earthquake seismic tremor.展开更多
Early oceans （〉520 Ma） were characterized by widespread water-column anoxia, stratification, and limited oxidant availability which are comparable to the chemical characteristics of modern marine sedimentary pore-w...Early oceans （〉520 Ma） were characterized by widespread water-column anoxia, stratification, and limited oxidant availability which are comparable to the chemical characteristics of modern marine sedimentary pore-waters in productive continental margins. Based on this similarity and our current understanding of the formation mechanism of early Earth ocean chemistry, we propose an idealized chemical zonation model for early oceans that includes the following redox zones （from shallow nearshore to deep offshore regions）： oxic, nitrogenous （NO3^-NO2^-enriched）, manganous-ferruginous （Mn^2＋ or Fe^2＋-enriched）, sulfidic （H2S-enriched）, methanic （CH4-enriched）, and ferruginous （Fe^2＋-enriched）. These zones were dynamically maintained by a combination of processes including surface-water oxygenation by atmospheric free oxygen, nitrate reduction beneath the chemocline, nearshore manganese-iron reduction, sulfate reduction, methanogenesis, and hydrothennal Fe^2＋ inputs from the deep ocean. Our modified ＂euxinic wedge＂ model expands on previous versions of this model, providing a more complete theoretical framework for the chemical zonation of early Earth oceans that helps to explain observations of unusual Mo-S-C isotope patterns. This model may provide a useful foundation for future studies of ocean chemistry evolution and elemental biogeochemical cycles in early Earth history.展开更多
文摘Elimination of human losses is the main and immediate task in the seismic vulnerability problem.The authors suggest the ways of development of seismic research and discussion of defense problems for reducing of seismic vulnerability. It is the ways of nonlinear seismology region. Unconditionally seism zoning and the theory of catastrophes allow reduce human losses and building destruction. But well-known isoseists are the private case of caustic catastrophe theory or seismo-acoustics, so seism zoning can be amounted to 6 elementary catastrophe forms. It will better help to predict seismic actions. The short-time local prediction of seismic events is general method for strong reducing of human losses. This method takes into account chaotic properties of stress fields and waves and the peculiarities of urban area. It bases on the natural seismo-emission phenomenon and is realized by long-time monitoring, which gives statistically and geographically continuous picture （chart） of seismic noise level inside geologic media. The instruments of this strategy are shock and pressure-proofed seismometers for long-time monitoring and control the state of geological media including underwater shelf areas. The authors think that the active protecting for cities and buildings as the best modem form of people safety consists in stress discharge of geologic media. Ultrasonic wave defense includes and bases on strong interaction between powerful waves from earthquake and ultrasonic wave train. The authors want to point out that the technical objects may be used lbr the investigation of earthquakes induced and some reasons of seismic vulnerability. Also reducing of seismic vulnerability contains as component kinetic acting on volcano at the pre-explosive stage. The interesting and important aspect of defense problem is observation of the inharmonic wave processes in the soil and quasi-constant forces as the nearest seismic analogue of radiation forces in nonlinear acoustics under powerful earthquake seismic tremor.
基金supported by the National Basic Research Program of China(Grant No.2013CB955704)National Natural Science Foundation of China(Grant No.41172030)support from the U.S.National Science Foundation,the NASA Exobiology Program,and the China University of Geosciences(Wuhan)(SKL-GPMR program GPMR201301,and SKL-BGEG program BGL21407)
文摘Early oceans （〉520 Ma） were characterized by widespread water-column anoxia, stratification, and limited oxidant availability which are comparable to the chemical characteristics of modern marine sedimentary pore-waters in productive continental margins. Based on this similarity and our current understanding of the formation mechanism of early Earth ocean chemistry, we propose an idealized chemical zonation model for early oceans that includes the following redox zones （from shallow nearshore to deep offshore regions）： oxic, nitrogenous （NO3^-NO2^-enriched）, manganous-ferruginous （Mn^2＋ or Fe^2＋-enriched）, sulfidic （H2S-enriched）, methanic （CH4-enriched）, and ferruginous （Fe^2＋-enriched）. These zones were dynamically maintained by a combination of processes including surface-water oxygenation by atmospheric free oxygen, nitrate reduction beneath the chemocline, nearshore manganese-iron reduction, sulfate reduction, methanogenesis, and hydrothennal Fe^2＋ inputs from the deep ocean. Our modified ＂euxinic wedge＂ model expands on previous versions of this model, providing a more complete theoretical framework for the chemical zonation of early Earth oceans that helps to explain observations of unusual Mo-S-C isotope patterns. This model may provide a useful foundation for future studies of ocean chemistry evolution and elemental biogeochemical cycles in early Earth history.
