Interpretation of the Omori law

The well-known Omori law is represented in the form of the differential equation describing the evolution of the aftershock activity. The interpretation of the evolution equation is suggested. It is based on the idea of deactivation of the faults in the vicinity of the main shock of the earthquake. The generalization of the Omori law with the allowance for the nonstationarity of the medium in the source, which is cooling after the main shock, is presented.     

改进的传染型余震序列模型

将有限幂律公式（LPL）应用到传染型余震序列模型（ETAS）中，并对原ETAS模型加以改进。以台湾集集地震早期余震序列为例，对原ETAS模型与改进的ETAS模型进行了对比分析，结果表明改进的ETAS模型要优于原ETAS模型。     

主震和余震--从大森公式到ETAS模型

介绍了从描述余震发生频次的大森公式到ＥＴＡＳ模型的发展过程;给出了ＥＴＡＳ模型的主要理论,主要内容包括条件强度函数、参数估计和模型选择;讨论了ＥＴＡＳ模型在地震活动性研究中的应用情况,尤其是在前兆平静和前震研究中的应用,并对该模型的优缺点进行了评价。     

Bayesian estimation of the Modified Omori Law parameters for the Iranian Plateau

The forecasting of large aftershocks is a preliminary and critical step in seismic hazard analysis and seismic risk management. From a statistical point of view, it relies entirely on the estimation of the properties of aftershock sequences using a set of laws with well-defined parameters. Since the frequentist and Bayesian approaches are common tools to assess these parameter values, we compare the two approaches for the Modified Omori Law and a selection of mainshock–aftershock sequences in the Iranian Plateau. There is a general agreement between the two methods, but the Bayesian appears to be more efficient as the number of recorded aftershocks decreases. Taking into account temporal variations of the b-value, the slope of the frequency-size distribution, the probability for the occurrence of strong aftershock, or larger main shock has been calculated in a finite time window using the parameters of the Modified Omori Law observed in the Iranian Plateau.     

Global Change and Health — The Good, The Bad and The Evidence

Debates over the merits and demerits of globalisation for health are increasingly polarised. Conclusions range from globalisation being essentially positive for health, albeit with a need to smooth out some rough edges, to one of utter condemnation, with adverse effects on the majority of the world's population. Anyone wading into this debate is immediately confronted by seemingly irreconcilable differences in ideology, opinion and interests. Both camps agree that global changes are occurring, and with them many of the determinants of population health status. While some skepticism persists about whether “globalisation” has value beyond being a fashionable buzzword, most agree that we need better understanding of these changes. Two difficult questions arise: (i) What are the health impacts of these changes; and (ii) how can we respond more effectively to them? To move beyond the stand-offs that have already formed within the health community, this paper reviews the main empirical evidence that currently exists, summarises key points of debate that remain, and suggests some ways forward for the research and policy communities. In particular, there is need for an informed and inclusive debate about the positive and negative health consequences of globalisation.     

四川地震震级与烈度区面积和震源深度的关系

本文按照地震地质分区,同时考虑7级以上地震的空间分布特征,分四川为鲜水河、松潘—龙门山及马边地震带等几个区带,对四川1900年以来既有仪器测定参数、又有宏观烈度考查的33个地震资料,应用多元线性回归分析方法,统计拟合出了震级与不同烈度区面积、烈度值、震源深度之间的多组关系式,其一般形式为:■相关系数R大都在0.90左右,用部分地震检验的结果表明,震级误差一般小于0.3,震源深度误差一般小于5公里,基本消除了离散情况,笔者用求得的关系式对1900年以前的有三条以上等震线的部分历史地震的震级、震源深度进行了标定,结果也比较令人满意。     

The fourth order geomagnetic multipole: The sedecimupole

Summary The nine coefficients of fourth order spherical harmonic functions in the expression for the potential of the main geomagnetic field are used to derive the nine parameters of a fourth order multipole. These nine parameters consist of the strength of the multipole, and four unit vectors or axes. The points of intersection of the axes with the surface of the Earth are called poles. Although movements of the poles over the period 1829 to 1965 are masked by random errors in the spherical harmonic coefficients, all of the axes show eastward components of drift since 1829, but two have drifted westward in later years to return almost to their initial 1829 positions. The strength of the fourth order multipole has shown a general increase, amounting to some 30 per cent of the 1829 value.     

The fifth order geomagnetic multipole: The duotrigintupole

Summary The notion of a dipole is generalized to the case of the fifth order spherical harmonic coefficients of the geomagnetic potential. The corresponding five axes and fifth order multipole strength are computed for ten epochs in the interval 1845 to 1965.     

The Moon

Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.     

The mesosphere

The mesosphere, which extends from about 50 to 90 km altitude, is an atmospheric region characterized by a negative gradient of solar energy absorption, and thus, temperature. Although the distribution of most minor constituents is dominated by photochemistry, vertical transport does have a pronounced effect on many of them. Hence, we discuss the basic dynamic principles and their application to the important mesopheric motions: acoustic-gravity waves, tides, planetary scale waves, and eddy motions.The most important minor electrically neutral constituents are compounds of oxygen, hydrogen and nitrogen. In fact, the allotropes of oxygen are in many ways the most significant because they screen out solar ultraviolet radiation and provide the principal source of mesospheric heating (absorption of solar UV by O₂ and ozone). We also discuss oxides of nitrogen and hydrogen which strongly influence the balance of odd oxygen (O and O₃). Brief discussions of the chemistry of carbon compounds and of excited species are also included.The chemistry of ionic species present in the mesosphere is very important because it strongly influences the propagationand absorption of radio waves. Because of ion clustering and negative-ion formation, such chemistry is extremely complex, and it is only very recently that we have begun to understand it. The current state of knowledge is discussed in some detail. The principles involved in constructing models for predicting the distribution of minor constituents, both neutral and ionic, are presented.     

用模式识别方法估计水库诱发地震危险性

水库蓄水后可能诱发的地震危险性估计是工程地震工作中的一项重要环节,其中可能诱发的地震强度是人们特别关注的要素。本文基于国内外41个水库地震震例,从目前对水库地震形成机理的认识水平出发,提取了15个可能的诱震指标,应用模式识别的一些方法对水库蓄水后的诱发地震危险性进行复因子评估,通过内符检验讨论了这些方法在水库诱发地震危险性上的估计效能,给出了其错误概率估计值,结果表明,这些方法能够相对客观和合理地评定水库蓄水后可能诱发的地震危险性水平大小,在工程上具有一定应用价值。     

三峡工程对坝下长江流量影响研究

根据长江水情的具体特点,采用Ｐｒｅｉｓｍａｎｎ隐式格式,建立了一个描述长江情的水动力学数值模式。以最佳拟合历史水文资料,重演历史水文过程为原则,率定数值模式中的各参数;并运行率定后的模式,进行三峡工程对坝下长江若干断面处流量影响的模拟预测。     

大同市地裂缝三维断层形变测量值与辅助温度的相关分析

简要介绍同车公司地裂缝观测站情况,以2013年至2016年数字化改造后的观测数据为基础,结合仪器工作原理,分析三维断层形变测量仪测值与观测仪两端辅助温度测值的关系。结果表明,地裂缝三维断层形变观测中,垂直向DFG观测受地裂缝两端辅助温度影响较显著,地裂缝垂直形变变化是热形变效应和断层运动信息的综合反映。     

风场对藻类在太湖中迁移影响的动力学研究

在Ｗｅｂｓｔｅｒ等人工作的基础上,以三维湖流为背景,考虑了波浪及藻类自身浮力的影响,建立了一个太湖梅梁湾三维藻类迁多模型,以研究在不同几场作用下藻类在湖泊中的迁移过程。模拟结果表明,不同风场对于藻类在湖泊中的水平及垂直分布影响很大,并且存在着一临界风速,其范围在２－３ｍ／ｓ之间,当几速小于临床风速时,水面可以拟看作水动力学光滑,没有波浪产生,在水表面藻类顺着风向迅速的向迎风岸的边漂移,形成藻类大量     

体视学对于睾丸生物学研究的贡献

男性和女性的生育控制问题是本世纪一个重要的生物学研究领域。女性生育的有效控制方法已存在好多年了，然而，用于男性的有效的方法还没有找到。近年来，人们试图确定荷尔蒙对精子产生的调节作用，期望找到与女性避孕同样有效并可接受的方法。睾丸包括生精管和裂隙腔，生精管中容纳的是滋养幼芽上皮细胞的Sertoli细胞，裂隙腔中容纳的是产生睾丸激素的Leydig细胞。在精子产生过程中，精原细胞通过有丝分裂繁殖，其下一代经过减数分裂产生单倍体圆形精子细胞，接着发生一系列复杂的形态变化成为成熟的长形精子细胞，成熟后的精子就具有受精能力。 维持幼芽上皮细胞的Sertoli细胞在人的一生中不发生大的变化。Sertoli细胞维持幼雅细胞的能力是有限的，但在不同人之间其能力有一个较大的变化范围。因而，Sertoli细胞的数目决定了睾丸产生精子的最大能力。对于精子产生的调节涉及到内分泌、副分泌和自分泌机制。体视学和各种形态测定工具已成为实验条件和自然条件下睾丸生物学研究的一把钥匙，这些研究包括了解Sertoli细胞的繁殖以及调节精原细胞转变为成熟细胞的效率的因素。从而提出精子发育的规律性，由荷尔蒙对精子产生调节作用的模型。     

A Geophysical Study Of The Ophiolite Complex And The Sedimentary Basins In The Northwest Part Of The Chalkidiki Peninsula (N. Greece)

The present work focuses on the study of the main ophiolite complex ofNorthern Greece, which is one of the dominant geological features in thebroader Aegean area, by the use of geophysical (gravity and magnetic)data. This ophiolite complex, which trends in a NW-SE direction, startsat the eastern part of the borders of Greece with F.Y.R.O.M. and continuesup to the southern part of the Chalkidiki Peninsula. The ophiolites mainlyconsist of dense, high-susceptibility peridotitic and gabbroic rocks. As aresult, the southwestern part of the ophiolitic complex, which crosses thenorthwestern part of the Chalkidiki-Peninsula, gives rise to both highamplitude aeromagnetic and Bouguer anomaly values. On the other hand,the Axios-Thermaikos basin, which is situated at the western border of theophiolitic complex, exhibits a deep sedimentary cover that results in lowBouguer anomaly values. The corresponding Bouguer anomaly decreasesto the southwest, indicating an increase of the sedimentary layer thicknessin that direction.2.5-D inversion was applied to both the aeromagnetic and the Bouguergravity data along several profiles. All the profiles were oriented normalto the main trend of the ophiolitic complex. Information from two deepboreholes, as well as the surface occurrence of the ophiolites was used asconstrains to the inversion scheme. The produced model shows an averagesedimentary thickness of 2.5 km along the coastline. From the joint inversionof the Bouguer and aeromagnetic anomaly data the existence of two ophioliticstripes is revealed. The first ``external' one is located in the southwest part, while the other ``internal' one to the northeast part of the belt. In the internal one, the depth extent of the ophiolites was estimated to range between 1 to 4 km. Moreover, the ophiolites were found to dip towards the northeast, but their dip varies from 20–45° in the northern part to 10–15° in the southern part of the stripe. For the ``external' stripe the extent of the ophiolitic bodies varies from northwest to southeast, reaching its highest depth of 5 km to the south. This stripe is also dipping towards the northeast with a dip of 10–15°.     

月球节点和太阳黑子活动与马边地区地震活动关系探讨

本文对月球每隔18．6年循环达其运行轨道最北节点N周期位置，和太阳黑子活动周期位相与马边－雷波－屏山区域地震活动的关系进行研究分析，发现，本区发生M≥3．6，级地震的“月－地”关系背景年，以及在“月－地”关系北景年对应的太阳黑子活动周期位相的特定条件下，存在因受特大黑子活动事件，引起太阳磁场极性变化的半周期和全周期为时间尺度的“日－月－地”高相关年的转折变异，激发本区破坏性地震或震群发生的时间规律，并用于对本区未来M≥5级地震活动的中期，短期预报。     

沐川5.7级地震及马边,雷波地震带的地震活动度异常特征

本文用地震活动度研究了马边、雷波地震带１９９４年１２月３０日沐川Ｍｓ５．７地震，并以该带历史地震作为比较，探讨了中强地震发生前地震活动度的异常特征。得出了中强地震发生前地震活动度具有可识别性的认识。