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991.
为提高标定仪器的技术性能和功能,满足台网地震遥测系统分段标定的使用要求,研制了BD—1型标定信号发生器.该仪器采用比较先进的单板机技术,用数字合成的方法产生标定需要的十八点频正弦波信号. 相似文献
992.
本文研究了青藏高原北缘第一个长约400km的MT监测剖面上所获得的5次5-7级地震前后的资料。着重分析了在相当于大陆多震层深度范围内壳内介质的多种MT参数(视电阻率、相位、主轴方位角、扭曲度等).这些MT参数在大范围内的同步-同相变化和局部区域之间的超前、滞后变化、相对变化幅度随震中距增大而衰减的特征,可能分别对应着构造孕育型大震的地区性场兆和构造运动型强震的区域性场兆,形成了地震活动大背景叠加小背景的一种链式关系。运用"MT监测优显参数"进行择优监测,将可能为大陆地震的震源物理发展过程和中短期预报提供丰富可靠的判据。 相似文献
993.
巴塘3次续发性中强地震震源的研究 总被引:1,自引:0,他引:1
本文使用CDSN宽频带数字地震波形记录,通过波谱分析研究了巴塘3次续发性中强地震震源的几何参数和动力参数,并同余震震源空间立体分布图像研究结果进行对比分析。 相似文献
994.
Lichenometry is a dating technique that has problems relating to questionable assumptions. The development of a size frequency approach, previously used in attempts to resolve some of the problems, is described and applied to the dating of four debris flows marginal to the San Rafael Glacier in Southern Chile. This study provides examples of the development's application, its problems and directions for further work. The size frequency approach, based on new assumptions, uses parameters derived from population size frequency distributions of the lichen species Placopsis patagonica to provide relative and absolute dating for rock surfaces. Changes in the shapes of distributions suggest the relative age of populations. Absolute dating is based on a curve (spanning a 24 year time period) derived from mean diameter size/age correlations. A stratified random sampling design permits the use of inferential statistics. Standard deviations and confidence intervals show error margins, the degree of relatedness between neighbouring populations, and populations that are anomalous. One-way analysis of variance is used to indicate where populations may safely be grouped. The size frequency approach appears to be particularly suitable for use on unstable debris flows where secondary movements are common. The approach also demonstrates that lichen growth and colonization are sensitive to aspect differences and other variations in microhabitat. 相似文献
995.
In the context of analysis of variance, Box and Cox (1964) developed a generalized technique for power transformation of frequency distributions to normality. It is here applied to geochemical data, based on the nonlinear optimization of skewness and kurtosis. The transform appears to be particularly well suited to the preprocessing of geochemical data prior to multivariate analysis. 相似文献
996.
在利用地面磁共振方法进行地下水探测时,要求发射频率与拉莫尔(Larmor)频率相同.由于地磁场的不均匀性和噪声干扰,实际测量时无法获得准确的Larmor频率,导致发生偏共振现象.如果假设磁共振或频率偏量未知时,反演得到的含水量和弛豫时间(T2*)将存在较大误差.为了解决未知Larmor频率情况下的准确探测问题,本文在频率环测量方案的基础上提出了双频磁共振探测方法,即只需知道Larmor频率的范围区间,通过区间外的两个频率进行偏共振激发,利用频率差值的一半作为频率偏量计算核函数,即可消除未知Larmor频率的影响.通过仿真实验,证明了在电阻率大于100 Ωm时,双频磁共振和偏共振的核函数偏差较小.对于双层含水层模型,双频磁共振和偏共振的信号偏差小于3 nV,因此得到双频磁共振信号可以用偏共振核函数进行反演.通过对假设磁共振、假设偏共振和双频磁共振反演结果的对比,可以得到在未知频率偏量和设定频率偏量改变时,双频磁共振均能得到准确的反演结果.但是,当环境噪声增加和电阻率降低时,反演结果的准确度降低.最后,通过长春市烧锅镇采集数据的反演结果与已知钻探资料进行对比,验证了双频磁共振探测方法的有效性和准确性. 相似文献
997.
Masaru Tsujiura 《Pure and Applied Geophysics》1983,121(4):573-600
Through the analyses of waveform and spectrum for two swarm sequences in the Kanto District, including the results from 15
earthquake swarsm obtained previously, the mechanism of the faulting process in earthquake swarms is clarified in more detail.
Earthquakes occurring in short time intervals consist mainly of events with similar waveforms andS-P times. These are called “earthquake families,” and many families are observed during a swarm sequence (70–80 percent); for
example, 15 families were observed in the 1983 Izu Peninsula earthquake swarm. The source spectra of earthquake families share
the same corner frequency, even though their low-frequency levels may differ by a factor as great as 1000, and the value of
the corner frequency depends on the size of the largest event in the family. Local variations of corner frequencies within
a factor of 25 are found among the earthquake swarms in the Kanto District. These observations suggest the existence of a
characteristic fault length depending on the swarm area, and its length may be responsible for the size of the largest event
in the family. The characteristic fault length is about 100 m for Ashio, about 400 m for the Izu Peninsula and about 2.5 km
for areas off the Chiba Prefecture, and the magnitudes of the largest events expected from these fault lengths are about 2.5,
4, and 6, respectively. 相似文献
998.
川西浅层储层地震“低频、强振幅”形成机理及陷井分析 总被引:1,自引:0,他引:1
黎家盆 《物探化探计算技术》2003,25(3):193-196
在川西地区浅层油气勘探开发过程中,已总结出地震“低频、强振幅”油气预测模式,并早已应用于勘探中。随着该区勘探开发程度的提高,该模式作为已成熟的油气预测方法在一些地区出现了预测失误。这里经分析了地震“低频、强振幅”的形成机理后总结出了模式预测中典型的“陷井”,并提出了降低模式预测风险的附加条件。 相似文献
999.
Martha Alvarez-Ramírez Joaquín Delgado 《Celestial Mechanics and Dynamical Astronomy》2003,87(4):371-381
We consider the symmetric planar (3 + 1)-body problem with finite masses m
1 = m
2 = 1, m
3 = µ and one small mass m
4 = . We count the number of central configurations of the restricted case = 0, where the finite masses remain in an equilateral triangle configuration, by means of the bifurcation diagram with as the parameter. The diagram shows a folding bifurcation at a value consistent with that found numerically by Meyer [9] and it is shown that for small > 0 the bifurcation diagram persists, thus leading to an exact count of central configurations and a folding bifurcation for small m
4 > 0. 相似文献
1000.