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1.
本文以中国地震局分析预报中心在APnet网上发布的地震目录为基础,对照<中国地震年鉴>、<中国震例>和哈佛大学的CMT目录,逐一筛选编制了一个包括震型(包括孤立型、主余型、多震型)、震级(包括面波震级和体波震级)、主压(张)应力P(T)轴方向、主破裂面等参数在内的震源参数目录.震级(面波震级)和地震类型采用<中国震例>或<中国地震年鉴>中的结果,体波震级、主压(张)应力P(T)轴方向采用CMT目录结果,大多数主破裂面参数是根据<中国震例>或<中国地震年鉴>中发表的主破裂面方向,选用CMT目录中相应的节面参数,少数地震的主破裂面参数是根据<中国地震年鉴>中发表的烈度分布的长轴方向,在CMT目录中选用相应的一个节面参数.在筛选过程中,对震群型地震只选用其中一个地震列入本研究的震源参数目录中,这样一共筛选出了101次地震.根据地震主破裂面的滑动角λ把发震断层分为走滑断层、逆断层和正断层三种情况,相应地把这三种性质断层上发生的地震分别称为走滑断层地震、正断层地震和逆断层地震. 相似文献
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地震静态应力触发模型的全球检验 总被引：19，自引：0，他引：19
运用1976～2000年哈佛大学矩心矩张量目录，采用地震对概念对地震静态应力触发模型进行检验．结果表明，从全球角度来看，地震静态应力触发效应确实存在，但只是一种很弱的效应．将地震分为正断层、逆断层、走滑断层等分别对静态应力触发模型进行检验，发现非走滑断层地震具有明显的触发效应，而走滑断层地震触发效应则不明显．按地震对中后续事件的延迟时间分为延迟时间t1天、t＜１天、t10天、t＜10天和1天 t10天5个时间段的地震对，分别对地震静态应力触发模型进行研究，发现静态应力触发效应在地震之后的短时间内不随延迟时间的变化而变化．对全球不同区域的地震静态应力触发情况的研究表明，消减带地震对的触发效应较为明显．为了研究地震静态应力触发模型在中国应用的可能性，对中国及邻区的地震进行了检验，发现就中国及邻区的地震类型而言（以走滑断层为主），不容易观测到地震静态应力触发现象． 相似文献
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通过研究中国大陆107次不同断层性质、不同震型、不同地区的5级以上地震的Ms与mb标度关系,用最小二乘法拟合得到:Ms=1 17mb-0 41。进一步分析发现:mb相同时,走滑断层地震的Ms大于倾滑断层地震的Ms;多震型地震的Ms大于孤立型地震的Ms。使用Ms与mb的这种关系,得到一种快速判定地震震型的方法,即对于走滑断层引起的地震,若Ms-1 17mb+0 16>0,则地震序列多数为多震型,再次发生较大或更大地震的可能性较大;对于倾滑断层引起的地震,若Ms-1 17mb+0 66<0,则地震为孤立型的可能性较大,再次发生较大或更大地震的可能性较小。 相似文献
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根据近场小孔径观测台网记录的余震序列资料，研究了2000年1月15日云南姚安MS6.4地震序列的地震物理过程. 用地震标定律关系估算主震的地震矩M0=1.58×1018N·m，矩震级MW=6.0，平均位错=0.63m，断层长度L=16.6km，断层宽度W=5.6km. 余震序列的高精度定位结果和能量分布走向，很好地证实了主震的断层破裂走向为N50°W，震区马尾菁断裂为主震发震构造，断层错动性质以右旋走滑为主. 用横波记录资料及波谱分析方法估算出余震的震源参数: 地震矩范围为1010～1016N·m，震源破裂半径a为80～500m，地震应力降范围为0.01～9.5MPa. 较大应力降(Δσ>1.0MPa)沿主断层线性排列，大应力降(Δσ>2.0MPa)与ML≥3.0级地震相关. 余震能量释放和高应力降的地震多发生在6.0～11km的深度范围，说明在这一深度范围内最大程度地集中了地壳中的应力. 相似文献
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基于细胞自动机模型,构建了由81×81个细胞单元组成非均匀二维单断层介质样本,研究了断层结构细观非均匀性以及相关模型参数变化对模拟输出结果和强度分布特征的影响。研究结果表明：结构非均匀性是影响地震活动性的控制性参量,随着非均匀程度的增强,地震事件数量增多,震级分布变得越来越均匀,破裂演化模式由相对“脆性”向“塑性”变化;介质结构的初始条件和应力加载的随机性对地震活动演化过程基本不产生影响。此外,应力降分配系数减小使b值主体线性段向大震级延伸;随着局部摩擦损耗系数增大,模拟地震事件的数量有所增加,大震级事件数量和震级衰减增强,b值主体线性区间变窄,使断层的变形破坏方式由相对“脆性”向“塑性”变化。这些对我们理解孕震过程的复杂性是有帮助的。 相似文献
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影响地震活动性因素的非均匀细胞自动机模拟研究 总被引：1，自引：0，他引：1
基于细胞自动机模型,构建了由81×81个细胞单元组成非均匀二维单断层介质样本,研究了断层结构细观非均匀性以及相关模型参数变化对模拟输出结果和强度分布特征的影响。研究结果表明:结构非均匀性是影响地震活动性的控制性参量,随着非均匀程度的增强,地震事件数量增多,震级分布变得越来越均匀,破裂演化模式由相对"脆性"向"塑性"变化;介质结构的初始条件和应力加载的随机性对地震活动演化过程基本不产生影响,此外,应力降分配系数减小使b值主体线性段向大震级延伸;随着局部摩擦损耗系数增大,模拟地震事件的数量有所增加,大震级事件数量和震级衰减增强b,值主体线性区间变窄,使断层的变形破坏方式由相对"脆性"向"塑性"变化。这些对理解孕震过程的复杂性是有帮助的。 相似文献
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根据已发布震源机制解目录（哈佛大学CMT）,将青藏高原东部及邻区划分为5个构造应力场分区,并对各分区的地震逐个计算其发震断层面上的固体潮汐正应力、剪应力、库仑破裂应力及相位角,分析潮汐应力分量对不同类型发震断层的作用效果及其随深度变化特征.基于库仑破裂应力判断准则,研究潮汐应力对各种类型地震的触发作用;基于Schuster检验方法,统计分析潮汐应力对各个震级档、不同构造类型地震的影响.综合运用上述两种分析方法,探讨潮汐应力对不同震级地震以及处于不同构造块体、发震断层、震源深度地震的触发机制.结果表明,潮汐应力对印度块体和拉萨块体的正断和逆断型地震,滇缅泰块体、印支块体和松潘-甘孜块体的走滑和斜滑型地震,川滇菱形块体的斜滑型地震均存在不同程度的触发效应,且触发效应的强弱依赖于震源深度、震级大小、发震断层类型及其所处区域构造应力场. 相似文献
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地震视应力及其物理意义的探讨 总被引：1，自引：0，他引：1
对NEIC宽频带地震辐射能量目录和哈佛CMT目录,给出全球震级大于5．5级的有能量记录的地震资料进行统计研究。首先,拟合得到全球浅源地震和不同类型地震平均视应力的大小和范围,验证了前人得到的“走滑型视应力大于倾滑型视应力”的结论;其次,对折合能量和地震矩关系分析得到：正断层型地震的折合能量随着地震矩增大而减小,而对于走滑型和逆冲型地震未得到前人给出的明确结论;对主震视应力和余震视应力的分析比较表明,它们在量值上没有规律性,必须要结合实际的地震事件,才能反映出它们之间大小关系的真正物理内涵,因为不同的主震可能对震源区的应力场有不同的影响——造成震源区应力场的应力集中（障碍体模式）,大部分余震的视应力高于主震视应力;或使应力场更加均匀（凹凸体模式）,大部分余震视应力低于主震视应力。这些结论对地震震源理论研究具有一定意义。 相似文献
9.
双节点有限元模拟直立走滑断裂地震位移场 总被引：2，自引：0，他引：2
结合位错理论和有限单元法，对介质横向不均匀性引起的直立走滑断裂地震水平位移场不对称性进行了数值模拟研究。结果表明，断层两侧介质泊松比和弹性模量的横向不均匀性，均可以引起直立走滑断层同震破裂及地震位移场的不对称性，其中，断层两侧介质的剪切模量比(刚度比)对直立走滑断裂地震位移场不对称性起主要作用。 相似文献
10.
内蒙古中西部地区中小地震矩震级研究 总被引：1，自引：1，他引：0
基于S震相"S窗"内的波形信号识别、品质因子Q(f)和22个台站场地响应,利用2009~2016年3月内蒙古中西部地区地震的波形资料,反演了182次中小地震的震源波谱参数,得到这些小震的零频幅值及其拐角频率,据此计算了这些地震的地震矩M_0、矩震级M_W和应力降Δσ。利用回归分析方法得到了近震震级与矩震级、矩震级与应力降的关系式。分析表明,近震震级与矩震级、矩震级与应力降呈线性关系。可见,将矩震级纳入地震的快报与正式目录中,可以丰富地震观测报告内容,更好地为地震应急和地震科研服务。 相似文献
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J. Vassal M. Menvielle Y. Cohen M. Dukhan V. Doumouya K. Boka O. Fambitakoye 《Annales Geophysicae》1998,16(6):677-697
In the framework of the French-Ivorian participation to the IEEY, a network of 10 electromagnetic stations were installed at African longitudes. The aim of this experiment was twofold: firstly, to study the magnetic signature of the equatorial electrojet on the one hand, and secondly, to characterize the induced electric field variations on the other hand. The first results of the magnetic field investigations were presented by Doumouya and coworkers. Those of the electric field experiment will be discussed in this study. The electromagnetic experiment will be described. The analysis of the electromagnetic transient variations was conducted in accordance with the classical distinction between quiet and disturbed magnetic situations. A morphological analysis of the recordings is given, taking into consideration successively quiet and disturbed magnetic situations, with the results interpreted in terms of the characterization of external and internal sources. Particular attention was paid to the effects of the source characteristics on the induced field of internal origin, and to the bias they may consequently cause to the results of electromagnetic probing of the Earth; the source effect in electromagnetic induction studies. During quiet magnetic situations, our results demonstrated the existence of two different sources. One of these, the SRE source, was responsible for most of the magnetic diurnal variation and corresponded to the well-known magnetic signature of the equatorial electrojet. The other source (the SR*E source) was responsible for most of the electric diurnal variation, and was also likely to be an ionospheric source. Electric and magnetic diurnal variations are therefore related to different ionospheric sources, and interpreting the electric diurnal variation as induced by the magnetic field diurnal variation is not relevant. Furthermore, the magnetotelluric probing of the upper mantle at dip equator latitudes with the electromagnetic diurnal variation is consequently impossible to perform. In the case of irregular variations, the source effect related to the equatorial electrojet is also discussed. A Gaussian model of equatorial electrojet was considered, and apparent resistivities were computed for two models of stratified Earth corresponding to the average resistive structure of the two tectonic provinces crossed by the profile: a sedimentary basin and a cratonic shield. The apparent resistivity curves were found to depend significantly on both the model used and the distance to the center of the electrojet. These numerical results confirm the existence of a daytime source effect related to the equatorial electrojet. Furthermore, we show that the results account for the observed differences between daytime and night-time apparent resistivity curves. In particular, it was shown that electromagnetic probing of the Earth using the classical Cagniard-Tikhonov magnetotelluric method is impossible with daytime recordings made at dip latitude stations. 相似文献
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利用中国地震局“十五”数字化地磁观测台网资料,分析了中国地区水平磁场静日变化场Sq（H）的时空分布特征,得出以下结论：Sq焦点的空间运行轨迹为：春秋季大致沿泉州贵阳一西昌一拉萨一狮泉河这样一个略倾斜于地磁赤道的条带运动,冬季倾斜条带北移约5°～10°;Sq（H）变幅由南北两侧向焦点方向递减;此外,相对于春秋季而言,冬季Sq焦点到达时间明显滞后,在中国境内的空间运行时间明显缩短。 相似文献
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利用~(210)Pb、~(137)Cs和~(241)Am计年法测算云南抚仙湖现代沉积速率 总被引：2，自引：0，他引：2
通过对云南抚仙湖沉积物柱芯样品的~(210)Pb、~(137)Cs和~(241)Am测试表明,柱芯剖面上有明显的1963年和1986年~(137)Cs蓄积峰,验证了1975年次级蓄积峰存在的可能性,这些峰形完好的蓄积峰对抚仙湖的现代沉积环境有明显的时标意义。利用~(137)Cs计年法得到抚仙湖沉积物自1963年、1975年及1986年以来到2007年的平均沉积速率分别为0.063g/(cm~2·a)、0.052g/(cm~2·a)和0.039g/(cm~2·a),说明了过去近五十年抚仙湖沉积速率整体上经历了一个由快到慢的过程。借助于~(241)Am的1963年蓄积峰可以提高~(137)Cs计年的准确性。根据~(210)Pb CRS计年模式,计算出每个样品深度所对应的年代,与~(137)Cs计年法比较存在一定的偏差,分析了两种计年方法存在差异性的原因。通过质量深度和年代分析,抚仙湖的沉积速率变化幅度比较大,表明抚仙湖近129年来的沉积环境不稳定,可能与相应历史时期的人类活动有密切的关系。 相似文献
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H. Rishbeth 《Annales Geophysicae》2000,18(7):730-739
This work reviews some aspects of the ionospheric F-layer in the vicinity of the geomagnetic equator. Starting with a historical introduction, brief summaries are given of the physics that makes the equatorial ionosphere so interesting, concentrating on the large-scale structure rather than the smaller-scale instability phenomena. Several individual topics are then discussed, including eclipse effects, the asymmetries of the equatorial trough, variations with longitude, the semiannual variation, the effects of the global thermospheric circulation, and finally the equatorial neutral thermosphere, including superrotation and possible topographic influences. 相似文献
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In this study,accumulation and distribution of Pb,Cu,Zn,Co,Ni,Mn and Fe in water,bottom sediments and four plant species (Myriophyllum verticillatum,Hydrocharis morsus-ranae,Nymphaea alba and Typha latifolia) were investigated in (C)ernek Lake of Kizihrmak Delta.The Kizdirmak Delta is one of the largest natural wetlands of Turkey and it is protected by the Ramsar convention since 1993.Selected physico-chemical parameters such as pH,conductivity and dissolved oxygen and also trace metal concentrations were monitored in water.All the parameters obtained were found higher than that of the national standards for the protected lakes and reserves.The accumulated amounts of various trace metals in bottom sediments and wetland plants were found in the following order of Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co ＞ Cu ＞ Pb and Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co respectively.The historical trace metal intake of Myriophyllum verticillatum,Hydrocharis morsus-ranae,Typha latifolia and Nymphaea alba were obtained higher than that of the toxic metal levels and these plants may be accepted as accumulators for the detected trace metals and also bioindicators in the historically polluted natural areas. 相似文献
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Arecibo (18.4 N, 66.7 W) incoherent scatter (IS) observations of electron density N(h) are compared with the International Reference Ionosphere (IRI-95) during midday (10/14 h), for summer, winter and equinox, at solar maximum (1981). The N(h) profiles below the F2 peak, are normalized to the peak density NmF2 of the F region and are then compared with the IRI-95 model using both the standard B0 (old option) and the Gulyaeva-B0 thickness (new option). The thickness parameter B0 is obtained from the observed electron density profiles and compared with those obtained from the IRI-95 using both the options. Our studies indicate that during summer and equinox, in general, the values of electron densities at all the heights given by the IRI model (new option), are generally larger than those obtained from IS measurements. However, during winter, the agreement between the IRI and the observed values is reasonably good in the bottom part of the F2 layer but IRI underestimates electron density at F1 layer heights. The IRI profiles obtained with the old option gives much better results than those generated with the new option. Compared to the observations, the IRI profiles are found to be much thicker using Gulyaeva-B0 option than using standard B0. 相似文献
19.
I. Charvátová 《Annales Geophysicae》2000,18(4):399-405
A solar activity cycle of about 2400 years has until now been of uncertain origin. Recent results indicate it is caused by solar inertial motion. First we describe the 178.7-year basic cycle of solar motion. The longer cycle, over an 8000 year interval, is found to average 2402.2 years. This corresponds to the Jupiter/Heliocentre/Barycentre alignments (9.8855 × 243). Within each cycle an exceptional segment of 370 years has been found characterized by a looping pattern by a trefoil or quasitrefoil geometry. Solar activity, evidenced by 14C tree-ring proxies, shows the same pattern. Solar motion is computable in advance, so this provides a basis for future predictive assessments. The next 370-year segment will occur between AD 2240 and 2610. 相似文献
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In this paper we investigate the tidal triggering evidence on the earthquakes of the seismic area of the Hellenic Arc using the Hist(ogram)Cum(mulation) method. We analyze the series of the earthquakes occurred in the area which is confined by the longitudes 22° and 28°E and latitudes 34° and 36°N in the time period from 1964 to 2012. In this time period 16,137 shallow and of intermediate depth earthquakes with ML up to 6.0 and 1,482 deep earthquakes with ML up to 6.2 occurred. The result of the this analysis indicate that the monthly variation of the frequencies of earthquake occurrence is in accordance with the period of the tidal lunar monthly variations, and the same happens with the corresponding daily variations of the frequencies of earthquake occurrence with the diurnal luni-solar (K1) and semidiurnal solar (S2) tidal variations. These results are in favor of a tidal triggering process on earthquakes when the stress in the focal area is near the critical level. 相似文献