An Evaluation of Seismic Decoupling and Underground Nuclear Test Monitoring Using High-Frequency Seismic Data (Paper 5R0913)
An Evaluation of Seismic Decoupling and Underground Nuclear Test Monitoring Using High-Frequency Seismic Data (Paper 5R0913)
复制标题
使用高频地震数据进行地震解耦和地下核试验监测的评估（论文 5R0913）
DOI：
10.1029/rg024i002p00143
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
E. Cranswick
中科院分区：
文献类型：
--
作者：
J. Evernden;C. Archambeau;E. Cranswick
通过使用高达30或40赫兹的高频地震数据，似乎可以有效地解决探测和识别低当量耦合和完全分离的地下核爆炸的问题。为了在使用这些数据时评估探测识别能力，有必要估计(1)在5-40赫兹的频段上来自爆炸和地震的P波和S波的频谱特征和相对幅度，(2)通过相关类型的地球结构在该频带上的信号传输特征，以及(3)在该频段上的记录系统和地面噪声特征。在这项研究中，依次审议了这些专题中的每一个，因为它们与区域和远震距离范围内低当量耦合和解耦爆炸的信号的探测和识别有关。然后考虑对特定假设网络探测和识别苏联境内爆炸的能力的估计(就信噪比是识别的一个重要因素而言)。这些对信号探测能力的估计为研究提供了中心焦点，因为它们有助于将各种和相当复杂的观测数据和理论转化为对监测能力的具体预测。在评估探测能力之后，将审议小事件的识别问题，特别强调在区域距离处的识别问题，在区域距离处，计算网络以提供高信噪比的信号。本研究的主要结果和结论如下：(1)在现有硬件条件下，地震系统噪声可以在频率至少高达30-40赫兹的安静场地被抑制到远低于地面噪声的水平：(2)各种地质环境中高频噪声的平均幅度很低，且随时间或季节变化不大；(3)在稳定的大陆地区和屏蔽区的区域距离范围内，高频P波和S波信号的传输效率几乎与1 Hz时一样高，在屏蔽区的有效Q因子分别约为9000和4000，而在构造区的有效Q约为1000；(4)经过适当设计和部署的苏联境内25个简单的三分量非阵列站和苏联周围15个类似站组成的网络，可以在高信噪比下探测位于苏联境内所有潜在解耦地点的完全解耦的1kt爆炸；(5)根据经验观测和理论预测的定量一致性推断，当使用大范围爆炸当量的低频数据时，基于可探测P波和S波的方法将有助于识别至少与完全解耦的1kt爆炸所期望的那样小的爆炸地震信号。
An effective solution to the problem of the detection and identification of low-yield coupled and fully decoupled underground nuclear explosions appears available via use of high-frequency seismic data ranging up to 30 or 40 Hz. In order to evaluate detection-identification capabilities when using such data, it is necessary to estimate (1) spectral characteristics and relative amplitudes of both P and S waves from explosions and earthquakes over the frequency band from 5 to 40 Hz, (2) signal transmission characteristics over this band through pertinent types of earth structure, and (3) recording system and ground noise characteristics over this frequency band. In this study, each of these topics is considered in turn as they relate to detection and discrimination of the signals from low-yield coupled and decoupled explosions in the regional and teleseismic distance ranges. Estimates of the capabilities of specific hypothetical networks to detect and identify (insofar as signal-to-noise ratio is an important factor in identification) explosions within the USSR are then considered. These estimates of signal detection capability provide the central focus for the study as they serve to translate diverse and rather complex sets of observational data and theory into concrete predictions of monitoring capability. Following the assessment of detection capabilities, the problem of identification of small events is considered, with particular emphasis on discrimination at regional distances where the network is calculated to provide signals of high signal-to-noise ratio. The principal results and conclusions of this study are as follows: (1) seismic system noise can be suppressed to levels well below ground noise at quiet sites up to frequencies at least as high as 30–40 Hz when using presently available hardware; (2) average amplitudes of high-frequency noise in a variety of geological environments are very low and change little with time or season; (3) transmission of high-frequency P and S wave signals in the regional distance range in stable continental areas and shields is nearly as efficient as at 1 Hz, with effective Q factors in shield areas being about 9000 and 4000 for high-frequency Pn and Sn, respectively, while the effective Q for Pn waves in tectonic areas is about 1000; (4) a properly designed and deployed network of 25 simple three-component nonarray stations internal to the USSR and 15 similar stations surrounding the USSR is predicted to be capable of multistation detection at high signal-to-noise ratio of fully decoupled 1-kt explosions located at all potential decoupling sites within the USSR; (5) by inference from the quantitative agreement of empirical observations and theoretical predictions, when using lower-frequency data over a great range of explosion yields, we conclude that procedures based on the use of both detectable P and S waves will serve to identify explosion-generated seismic signals at least as small as those expected from a fully decoupled 1-kt explosion.