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作者根据位错模型导出了震级不仅与震中烈度和震源深度有关,而且与极震区面积有关。震中烈度通过应力降和震级联系起来,而极震区面积则通过位错面的面积或震源体积和震级联系起来,使震级与烈度的物理联系更加明确。 用我国的61个浅源地震资料,用逐步回归方法计算出震级M与震中烈度I0、极震区面积（面积单位为平方公里）A0的关系为: M=3.53+0.039I02+0.0178（Ig A0）3,还分别计算出震级与6-8度区面积A6、A7、A8的关系为: M=3.63+0.72 Ig A6, M=5.34+0.718（Ig A7）·（IgIg A7）, M=5.92+0.104（Ig A8）2。并外推出震级与5度区面积A5的关系为: M=3.03+0.72 Ig A5。 利用这些关系式来确定历史地震震级比仅考虑震中烈度来确定有较好的效果。 相似文献
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文中使用了一个新的量规函数σ300（Δ）,它是基于面波传播理论,考虑了面波的几何扩散、非弹性吸收、频散衰减以及面波优势周期随震中距的变化导出的,取全球平均Q=300。在震中距Δ=20°-160°的范围内与IASPEI推荐的面波震级的量规函数σIASPEI（Δ）一致,又推广了σIASPEI（Δ）的震中距使用范围,从1.0°-179°,以及可使用的面波周期范围（7.5-30s）,因此它更适合我国由中周期宽频带SK仪组成的台网情况。若采用此量规函数σ300（Δ）和进行方位角改正,则可使我国台网测出的Ms与国际地震中心（ISC）测出的一致,震级误差降到0.19级,此误差与苏联台网的误差一样。 相似文献
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本文探討了Gotz逆轉效应中,单色天頂散射光强I3112（?）的有效散射高度hE的上升过程。首先从理論上証明:hE并非沿高度連續的上升,而是跳跃上升的。然后用实际观測数据的計算,証实了理論結果。由此并指出,由于hE的跳跃,那么在应用逆轉效应,建立測定大气臭氧垂直分布方法时,如果将大气分层較多,那么可能在臭氧层中下部所得的結果,是不唯一的。基于上述結果,进一步研究了方法B,发現目前国际上通用的,由Ramanathan与Davo所給出的逆轉方法B的解是不唯的。这些解之間有着亘大的差异。因此以該方法計算出的各层臭氧含量,并不能肯定大气臭氧的垂直分布情况。 相似文献
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本文提出爆炸地震的能量转换系数计算公式 α=(k·10-2)3/n·10-3和 α=2.03·10-3 multiply from i=1 to 6 （Fi）上式中k、n为爆炸地震效应的统计参数。下式中Fi（i=1,2,…,6）为反映爆炸方式和场地条件的影响因子。 利用爆炸地震的能量转换系数α,还可建立不同爆炸方式的药量等效系数η: η=α/α0和爆炸震级估算公式 M=4.42+0.53logαQ.上式中α0为井下组合（标准）爆破的转换系数。下式中Q为以吨（t）为单位的药量（TNT）。 相似文献
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在任意相邻两个接收点各种校正条件相等的情况下,由公式t=1/v××（xi2-2xoxi+4h2）1/2可以导出下列方程组:共中A,B,C,…,G是常量;Xi=v2,Yi=xo,Zj=h2。 v--岩石中的地震波速度, h--爆炸点到界面垂距的平均值, xo--对应tmin的横坐标。解上面方程组便求得v,h,xo,。已知v,h,xo,利用交点法可求得界面上任意点A的坐标表达式: zA-Z0/2=-x0/Z0（xA-x0/2）, ZA/Z0=（XA-（i+1）△x）/（x0-（i+1）△x） 解此方程组便得到界面上任意点的坐标（zA,xA）。此外,利用椭圆法也可求得下列方程组: 解此方程组,也可求得界面上点的坐标。若界面上各点坐标已知,把已知参量送到机器里,便可自动描绘出反射界面。现代电子计算机的出现和使用为各种生产的自动化开辟了广阔的道路。同样,野外地球物理探矿的生产自动化也是目前所迫切需要的。本文试图讨论关于地球物理探矿中反射波地震界面自动勾制的数学原理。根据这一原理,电子计算机的设计和制造家们不难设计和制造出为此用途的专用电子计算机--数字机和模拟机,也不难根据这一原理编成解题程序,在通用电子计算机上找出问题的解答。 相似文献
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本文推导并评价了一个新的计算视复电阻率的近似公式,其视振幅表达式为|ρs（ω）|≈ρs（ω）|ρs（ω）=ρs（ω）|,视相位表达式为φs（ω）≈sum from i=1 to n（Bi（ω）φi（ω））,这里Bi（ω）是按各介质复电阻率振幅计算的稀释系数。此近似公式比迄今为止已发表过的同类近似公式都精确,可在频率域激电法数值模拟计算视复电阻率时应用。 相似文献
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一、 4Be9是鈹元素唯一的稳定同位素,可以利用鈹核的光致核反应:4Be9（γ,n）4Be8来測定岩石样品中鈹的合量;此反应要求γ射綫的能量大于中子在鈹核中的結合能。 相似文献
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从断裂力学观点研究地震的破裂过程和地震预报 总被引：29，自引：2，他引：27
把断裂力学中的应变能释放率公式和裂纹错开位移公式运用到地震破裂中来,再用震级-能量公式logεe=α1M+α2,对于走向滑动、倾向滑动和圆盘形剪切破裂找到了震源参数和地壳应力状态之间的内在联系,汇总在表2。对于走滑断层情形,关系式如下: （1） （2） （3） （4）应力降 （5）平均应力 （6）用Mo和L2W求区域应力公式式中,M为震级,L、W为断层长度和宽度,η为地震效率,τ0为区域剪切应力,τy为剪切屈服强度,μ为刚性系数,v为泊松比,为平均位错,M0为地震矩。 利用（6）式或（1）式,在实验室测出地壳状态下屈服强度τy,后,可用地震观测资料算出区域剪切应力τ0。 上述关系式和目前流行的震源参数之间的关系式有很大的差别。原因是以往只考虑了破裂的初态和终态,没有考虑破裂过程。而断裂力学恰恰是考虑了破裂过程。 相似文献
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大地震的震源机制及地震矩、应力降等参数,不(又对认识地震的破裂过程,而且对预报强地面运动都是非常重要的。一些文章对板内地震应力降的特点、地震矩与高频源谱的关系及区域特征的讨论,使我们可直接由长周期体波或面波得出的地震矩M0估计出不同地区中大地震的高频源谱,以供强地面运动预报参考。 由于对发生在中国板内的1976年11月6日盐源地震（Ms=6.5）和1976年11月15日宁河地震（Ms=6.3）的震源参数还没有详尽的报道;另外,对1973年7月14日 相似文献
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本文应用模糊数学方法从给定地区的地震目录中识别出地震簇.这些地震簇由一系列时空相关的地震组成,每一次强震前都可能有其地震簇出现.两次地震的函数由以下公式来确定:eij=1e-1t+2e-2s计算出某一地区所有 MM0地震相互之间的联系强度,并取一个经验参数之后,就可以根据编网原则识别出地震簇.利用地震簇,可以把强震的地震活动性图象识别得更清楚,简单和定量化.此方法曾用于我国大华北及西南地区的地震簇识别与地震活动图象研究.清楚地识别出了13次大震(M6.5)的地震簇.研究了它们的时空特性.近似建立了 lg△t,lgL,lgS 与震级 M 间的线性经验关系,此处△t,L,S 分别表示地震簇的前兆时间(持续时间)及其震中分布的最大线度与面积.显然,这些关系式对地震预报研究可能有一定用途. 相似文献
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三维物性分布的位场计算 总被引：11，自引：3，他引：11
本文在连续层状模型的基础上,将Parker位场公式推广到更具一般性的两种三维物性分布模型中。此时岩石的密度ρ和磁化强度J不仅在水平方向上可以任意变化,而且在深度上可依指数或线性函数形式变化。新的位场公式仍具有严密而简明的特点。结合圣安德烈斯断层带的重力反演,介绍了它的应用、模型分解和双界面同时反演的技术。 相似文献
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CHARACTERISTICS OF TECTONIC STRESS FIELD OF THE XIAOWAN RESERVOIR BEFORE AND AFTER THE IMPOUNDMENT 
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下载免费PDF全文 Using the seismic waveform data of Xiaowan seismic network and Yunnan seismic network, we determined the focal mechanisms of 36 earthquakes(ML ≥ 3.0)from Jun. 2005 to Dec. 2008 and 51 earthquakes(ML ≥ 2.5)from Jan. 2009 to Dec. 2015 by generalized polarity and amplitude technique.
We inverted tectonic stress field of the Xiaowan reservoir before impounding, using the focal mechanisms of 36 earthquakes(ML ≥ 3.0)from Jun. 2005 to Dec. 2008 and CAP solutions of 58 earthquakes(ML ≥ 4.0)collected and the solutions in the Global Centroid Moment Tensor(GCMT)catalog; We inverted local stress field of the reservoir-triggered earthquake clustering area, using 51 earthquakes(ML ≥ 2.5)from Jan. 2009 to Dec. 2015.
Focal mechanisms statistics show that, the Weixi-Qiaohou Fault is the seismic fault. Focal mechanisms were strike-slip type in initial stage, but normal fault type in later stage. Focal depths statistics of 51 earthquakes(ML ≥ 2.5)show that, the average value of focal depths in period Ⅰ, period Ⅱ and period Ⅲ are 8.2km, 7.3km and 7.8km respectively and the standard deviations are 4.3km, 3.5km and 6.0km respectively. The average value of focal depths is basically stable in different period, only the standard deviation is slightly different. Therefore, there is not positive connection between focal depth and deviation of focal mechanisms. What's more, there are 2 earthquakes(number 46 and number 47 in Fig.5 and Table 3)with almost the same magnitude, epicenter and focal depth, but they have different faulting types as normal and strike-slip. The focal mechanism of event No.46 is strike:302°, dip:40° and rake:-97° for plane Ⅰ, however, the focal mechanism of event No.47 is strike:292°, dip:82° and rake:140° for plane Ⅰ. Likewise, earthquake of number 3 and number 18 have similar characteristic. Therefore, the obvious focal mechanism difference of similar earthquake pair indicates the complexity of Weixi-Qiaohou Fault.
Considering the quiet-active character of reservoir-triggered earthquakes, we discussed the change of local stress field in different period. The σ1 of tectonic stress field was in the near-south direction, with a dip angle of 14° before the impoundment, however, the direction of σ1 of local stress field changed continuously, with the dip angle getting larger after the impoundment. The direction of σ1 of local stress field of reservoir-triggered earthquake clustering area is close to the strike of Weixi-Qiaohou Fault, and reservoir impoundment increased the shear stress in the fault, so the weakening of fault was beneficial to trigger earthquakes. Comprehensive analysis suggests that fluid permeation and pore pressure diffusion caused by the water impounding, and the weakening of fault caused by local stress field are the key factors to trigger earthquake in the Xiaowan reservoir. 相似文献
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RESEARCH ON CHARACTERISTICS OF THE FOCAL MECHANISM SOLUTIONS CONSISTENCY OF RUSHAN EARTHQUAKE SEQUENCE,SHANDONG PROVINCE 下载免费PDF全文
下载免费PDF全文 Many small earthquakes occurred intensively and continuously and formed an earthquake sequence after the ML3.8 earthquake happened at Rushan County, Shandong Province on October 1, 2013. Up to March, 2017, more than 13 000 events have been recorded, with 3 429 locatable shocks, of which 31 events with ML ≥ 3.0. This sequence is rarely seen in East China for its extraordinary long duration and the extremely high frequency of aftershocks. To track the developing tendency of the earthquake sequence accurately, 20 temporary seismometers were arranged to monitor the sequence activities around the epicenter of the sequence since May 6, 2014. Firstly, this paper adopts double difference method to relocate the 1 418 earthquakes of ML ≥ 1.0 recorded by temporary seismometers in the Rushan earthquake sequence (May 7, 2014 to December 31, 2016), the result shows that the Rushan earthquake sequence mainly extends along NWW-SEE and forms a rectangular activity belt of about 4km long and 3km wide. In addition, the seismogenic fault of Rushan earthquake sequence stretches along NWW-SEE with nearly vertical strike-slip movement and a small amount of thrust component. Then we apply the P-wave initial motion and CAP to invert the focal mechanism of earthquakes with ML ≥ 1.5 in the study area. The earthquakes can be divided into several categories, including 3 normal fault earthquakes (0.9%), 3 normal-slip earthquakes (0.9%), 229 strike-slip earthquakes (65.8%), 18 thrust fault earthquakes (5.2%), 37 thrust-slip earthquakes (10.6%)and 58 undefined (16.6%). Most earthquakes had a strike-slip mechanism in Rushan (65.8%), which is one of the intrinsic characteristics of the stress field. According to the focal mechanism solutions, we further utilized the LSIB method (Linear stress inversion bootstrap)to invert the stress tensor of Rushan area. The result shows that the azimuth and plunge of three principal stress (σ1, σ2, σ3) axes are 25°, 10°; 286°, 45°; 125°, 43°, respectively. Based on the stress field inversion results, we calculated the focal mechanism solutions consistency parameter (θ)and the angle (θ1)between σ1 and P axis. The trend lines of θ and θ1 were relatively stable with small fluctuation near the average line over time. Furthermore, the earthquake sequence can be divided into three stages based on θ and θ1 values. The first stage is before September 16, 2014, and the variation of the θ and θ1 values is relatively smooth with short period. All focal mechanism solutions of the three ML ≥ 3.0 earthquakes exhibited consistence. The second stage started from September 16, 2014 to July 1, 2015, the fluctuation range of θ and θ1 values is larger than that of the first stage with a relative longer period. The last stage is after July 1, 2015, values of θ and θ1 gradually changed to a periodic change, three out of the four ML ≥ 3.0 earthquakes (strike-slip type)displayed a good consistency. Spatially, earthquakes occurred mainly in green, yellow-red regions, and the focal mechanism parameters consistency θ was dominant near the green region (around the average value), which presents a steady state, and the spatial locations are concordant with the distribution of θ value. Moreover, all of ML ≥ 3.0 earthquakes are located in the transitional region from the mean value to lower value area or region below the mean value area, which also indicates the centralized stress field of the region. 相似文献
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本文叙述了我国现行的北京地震台面波震级 Ms 公式的由来, 所使用的公式为Ms=log(A/T)max+(△)系以古登堡-里克特(Gutenberg-Richter)对帕萨迪纳(Pasadena)地震台测定的面波震级为标准, 由国际上与该标准一致的六个著名地震台的面波平均震级制定出北京地震台测定面波震级的起算函数(△).当震中距离△=8-130得到公式(△)=(1.660.09)log△+(3.500.14)对于△=130-180之间的公式, 我们结合中国地震观测的实际情况将吸收系数项作了改进, 求得半经验半理论公式为(△)=6.775+1/2[(2.147e-0.04465△+1.325)(△-90)10-2logsin△+1/3(log△-1.954)]为了提高面波定震级的精确度, 将北京地震台的面波震级标准推广到全国十二个基准台, 利用360个地震的数据算出了各台的台基校正值, 提高了测定面波震级的一致性. 相似文献
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在分析了对峰值加速度 PGA 的影响因素之后,我们发现构造环境剪应力场参数τ0对 PGA起了重要的作用,将τ0引入 PGA 的预测公式中,同时考虑了 PGA 对频率的依赖性。大地震的PGA 的优越频率 fa 较低,小地震的 fa 较高.因此,小地震的衰减系数较大,PGA 衰减较快。基于上述两点改进,提出了新的 PGA 预测公式。在该公式中,构造环境应力场、震级、距离和场地条件是预测将来强地面运动的重要变量。此公式有很大的适用范围,可以用于大地震（矩震级 Mw=6-7.8）,也可以用于较小地震（Mw=3-6）的 PGA 预测;在考虑了世界各个地区不同的构造环境应力值水平以后,新预测公式可以应用于世界不同地区（例如美国加州和中国华北、西南等）。用实际观测资料检验结果表明,预测效果良好。 相似文献
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On July 31st, 2016, an earthquake of MS5.4 occurred in Cangwu County, Guangxi Zhuang Autonomous Region, which is the first MS ≥ 5.0 earthquake in coastal areas of southern China in the past 17a. The moderate earthquake activities have come into a comparatively quiet period in coastal areas of southern China for decades, so the study about the Cangwu MS5.4 earthquake is very important. However, differernt research institutions and scholars have got different results for the focal depth of the Cangwu MS5.4 earthquake. For this reason, we further measured the focal depth by using CAP method and sPL phase method.
sPL phase was first put forward by Chong in 2010. It is often observed between P and S wave of continental earthquakes with epicentral distance of about 30km to 50km. The energy of sPL phase is mainly concentrated on the radial component. Arrival time difference between sPL phase and direct P wave is insensitive to epicentral distancs, but increases almost linearly with the increase of focal depth. Based on these characteristics and advantages, sPL phase method is chosen to measure the focal depth of Cangwu MS5.4 earthquake in the paper.
First of all, we selected the broadband waveform data through seismic stations distributed mainly in Guangxi and adjacent provinces from Data Management Centre of China National Seismic Network and Guangxi Earthquake Networks Center. And an appropriate velocity model of Cangwu area was constructed by the teleseismic receiver function method. Then, the focal mechanism and focal depth of Cangwu MS5.4 earthquake were determined by using the CAP(Cut and Paste)method. Next, we compared the synthetic waveforms simulated by F-K forward method of different focal depth models with the actual observed waveforms. According to the difference of arrival times between sPL and Pg phases, we finally obtained the focal depth of Cangwu earthquake. The results show that the focal depth is 11km measured by CAP method and 9km by sPL phase method. Based on the focal mechanism solution, isoseismal shapes, aftershocks distributions and investigation on spot, we conclude that the Cangwu MS5.4 earthquake is a left-lateral strike-slip earthquake which occurred in the upper crust. Our preliminary analysis considers that the seismogenic structure of Cangwu earthquake is a north-northwest branch fault, and the control fault of this earthquake is the Hejie-Xiaying Fault. 相似文献