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951.
针对地震静校正存在的非线性和多参数性等问题,本文提出了一种全局优化的剩余静校正方法.在模型更新规则上,把模拟退火方法和均匀优化设计方法结合在一起,使模型的更新更为合理,从而加快了搜寻全局最优解的速度.同时提出了模型的不同分量的温度参数和退火过程的选取方式,把温度参数的选取与地震剖面的能量联系起来,使温度参数的选取具有自适应的特点.该方法克服了常规模拟退火方法所具有的寻优空间不均匀以及退火参数需通过多次试验选取的缺陷.通过实际地震资料的计算证明,本文提出的方法对地震静校正问题合理而有效. 相似文献
952.
岩石圈流变机制的确定及影响岩石圈流变强度的因素 总被引:20,自引:2,他引:20
讨论了确定岩石圈流变强度中存在的问题,根据Byerlee定律,给出了在Anderson断层系统下三种断层的摩擦滑动强度公式,利用小标本实验结果外推,用大标本实验结果作约束,得到岩石圈几种典型岩石的脆性破裂规律,利用上述结果和传统的方法,分别得到了鄂尔多斯和山西裂谷两个典型地区的流变强度随深度的变化。结果表明,以往的计算对岩石圈流变强度的估计过高,对脆性形变区估计不足,流变机制估计不对;岩石圈有力学分层的特性,但各地分层的深度范围不同,使得成层和力学作用变得复杂,讨论了水、应变率以及多相矿物对流变强度的影响。 相似文献
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—?This paper reports results from two recent monitoring experiments in Wyoming. Broadband seismic recordings of kiloton class delay-fired cast blasts and instantaneous calibration shots in the Black Thunder coal mine were made at four azimuths at ranges from 1° to 2°. The primary focus of this experiment was to observe and to explain low-frequency signals that can be seen at all azimuths and should routinely propagate above noise to mid-regional distances where most events will be recorded by International Monitoring System (IMS) stations.¶The recordings clearly demonstrate that large millisecond delay-fired cast blasts routinely produce seismic signals that have significant spectral modulations below 10?Hz. These modulations are independent of time, the azimuth from the source and the orientation of the sensor. Low-frequency modulations below 5?Hz are seen beyond 9°. The modulations are not due to resonance as they are not produced by the calibration shots. Linear elastic modeling of the blasts that is guided by mine-blast reports fails to reproduce the fine detail of these modulations but clearly indicates that the enhanced “spectral roughness” is due to long interrow delays and source finiteness. The mismatch between the data and the synthetics is likely due to source processes, such as nonlinear interactions between shots, that are poorly understood and to other effects, such as variations of shot time and yield from planned values, that are known to be omnipresent but cannot be described accurately. A variant of the Automated Time-Frequency Discriminant (Hedlin, 1998b), which uses low-frequency spectral modulations, effectively separates these events from the calibration shots.¶The experiment also provided evidence that kiloton class cast blasts consistently yield energetic 2–10 second surface waves. The surface waves are strongly dependent on azimuth but are seen beyond 9°. Physical modeling of these events indicates that the surface waves are due mainly to the extended source duration and to a lesser extent to the slap-down of spalled material. The directionality is largely a path effect. A discriminant that is based on the partitioning of energy between surface and body waves routinely separates these events from the calibration shots.¶The Powder River Basin has essentially no natural seismic activity. How these mining events compare to earthquake observations remains to be determined. 相似文献
956.
拱坝非线性地震反应分析 总被引:2,自引:0,他引:2
本文根据一致粘弹性模型的概念,引入应变率的影响,将混凝土静态William-Warnke三参数模型改造成一致粘塑性William-Warnke三参数本构模型,并用这个模型对某高拱坝进行了非线性地震响应分析,与线弹性模型和应变率无关的William-Warnke三参数模型的结果进行了比较,初步探讨了应变率对拱坝地震反应的影响。 相似文献
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Che Yong-tai Yu Jin-zi Zhang Shu-liang Fan Xue-fang Guo Jun-jie Zhang Tian-yuan Yang Jin-lan 《地震学报(英文版)》2002,15(2):226-233
A lot of slow fluctuations of water level have been observed in the original recording maps of subsurface fluid in Well Shuozhou,
Shanxi Province. Some typical recording maps of the “precursors” are introduced in the paper and the features of the “precursors”
recorded by the well are analyzed. The results show that 38% strong earthquakes possess this kind of record, which has a fluctuation
period arranging from several to tens of minutes and appear mostly two days before the earthquakes. Moreover, the mechanism,
transmission and responding conditions of well water level are discussed, as well as the scientific meaning and practical
value of the “precursor” of the well water level in earthquake predictions.
Foundation item: State Natural Science Foundation of China (19973011). 相似文献
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