共查询到20条相似文献，搜索用时 148 毫秒
1.
开展严格而客观的地震灾害风险评估与真实地震活动对比测试,是进行任何负责任的地震灾害风险评估的必要前提。针对意大利境内实际发生的地震活动,将经典概率性方法(PSHA)得到的意大利抗震标准的参考灾害图与基于新的确定性方法(NDSHA)获取的可供参考的地震动图进行了交叉对比和测试。通过对大量可能地震的真实地面运动的模拟,结果表明,NDSHA方法可以给出可靠的设计地震的合理定义。NDSHA的灵活性可用于解释地震复发周期性,并可用于产出特定复发周期的地面运动图,以便与PSHA方法所获取的地面运动图进行直接对比分析。 相似文献
2.
3.
本文简介确定性及非确定性问题,讨论了二者之间的关系及其在地学中应用的可能性与展望。主要是谈方法论问题,应属于软科学范畴。 相似文献
4.
5.
地震危险性概率分析(PSHA)是目前最广泛应用于地震灾害与风险性评估的方法。然而它在计算中却存在着一个错误:把强地面运动衰减关系(一个函数)的条件超越概率等同于强地面运动误差(一个变量)的超越概率。这个错误导致了运用强地面运动误差(空间分布特征)去外推强地面运动的发生(时间分布特征)或称之为遍历性假设,同时也造成了对PSHA理解和应用上的困难。本文推导出新的灾害计算方法(称之为KY-PSHA)来纠正这种错误。 相似文献
6.
7.
引言概率性地震危险性分析(PSHA)是一种涉及多学科的工作,它需要诸如区域地震构造学、地震特征和重复性、地震动形成、地震波传播以及局部场地效应的多种知识。这些资料组成概率模型,可提供任一场地的地震动参数的年超越概率。最近 相似文献
8.
设定地震及其烈度影响判别 总被引：1，自引：0，他引：1
设定地震常用于震害预测、地震小区划和重大工程选址,烈度衰减模型反映了地震引起的地面震动及其影响的强弱程度分布。设定地震包括确定性和非确定性设定两种方法,确定性方法基于构造或历史地震,非确定性方法是基于概率危险性方法,用于估计区域或城市未来可能遭遇的地震危险。缺失等震线或震害记载不详的历史地震和概率设定地震都不能确切地反映地震破坏影响,借助于烈度衰减关系模型和GIS,可直观地判别其影响分布情况,便于设定地震的取舍。 相似文献
9.
10.
地震危险性分析方法的回顾 总被引：1，自引：0，他引：1
地震危险性分析方法的回顾［伊朗］米尔扎依引言地震危险性分析可以分成经验的－统计的、确定性的和概率的等几类方法。经验的方法直接根据历史地震资料和古地震资料来确定地震活动性和评定场点的地震危险性；在确定性分析方法里，表示第四纪或近代地壳活动证据的断层或者... 相似文献
11.
Jens-Uwe Kl��gel 《Pure and Applied Geophysics》2011,168(1-2):27-53
The large uncertainty associated with the prediction of future earthquakes is usually regarded as the main reason for increased hazard estimates which have resulted from some recent large scale probabilistic seismic hazard analysis studies (e.g. the PEGASOS study in Switzerland and the Yucca Mountain study in the USA). It is frequently overlooked that such increased hazard estimates are characteristic for a single specific method of probabilistic seismic hazard analysis (PSHA): the traditional (Cornell?CMcGuire) PSHA method which has found its highest level of sophistication in the SSHAC probability method. Based on a review of the SSHAC probability model and its application in the PEGASOS project, it is shown that the surprising results of recent PSHA studies can be explained to a large extent by the uncertainty model used in traditional PSHA, which deviates from the state of the art in mathematics and risk analysis. This uncertainty model, the Ang?CTang uncertainty model, mixes concepts of decision theory with probabilistic hazard assessment methods leading to an overestimation of uncertainty in comparison to empirical evidence. Although expert knowledge can be a valuable source of scientific information, its incorporation into the SSHAC probability method does not resolve the issue of inflating uncertainties in PSHA results. Other, more data driven, PSHA approaches in use in some European countries are less vulnerable to this effect. The most valuable alternative to traditional PSHA is the direct probabilistic scenario-based approach, which is closely linked with emerging neo-deterministic methods based on waveform modelling. 相似文献
12.
13.
Continuous Global Positioning System (CGPS) position time series from eastern North America constrain the pattern and magnitude of regional crustal deformation. Initial analysis delineates consistent uplift patterns, as expected from glacial isostatic adjustment (GIA) predictions, but the associated horizontal deformation is not definitive, in part due to the short time periods for a significant number of the available stations. We employ an eigenpattern decomposition in order to define a unique, finite set of deformation patterns for this continuous GPS data. Similar in nature to the empirical orthogonal functions historically employed in the analysis of atmospheric and oceanographic phenomena, the method derives the eigenvalues and eigenstates from the diagonalization of the correlation matrix using a Karhunen–Loeve expansion (KLE). The KLE technique is used to identify the important modes in both time and space for the CGPS data, modes that potentially include signals such as horizontal and vertical GIA, tectonic strain, and seasonal effects. Here we filter both the vertical and horizontal velocity patterns on different spatiotemporal scales in order to study the potential geophysical sources, after the removal of correlated and random noise. The method is successful in disaggregating the linear vertical signal from more variable and less spatially correlated signals. The vertical and horizontal results are compared to the predictions of the ICE-3G GIA loading model with a number of plausible mantle viscosity profiles. The horizontal velocity analysis allows for qualitative differentiation between several potential GIA models and suggests that, with longer time series, this technique can be employed to remove correlated noise and improve estimates of crustal strain patterns and their sources. 相似文献
15.
16.
17.
频率-波数分析基础理论及上海地震台阵响应分析 总被引：5，自引：0，他引：5
自1960年开始，地震台阵技术迅猛发展，给地震学研究带来了新的冲击。作为一种新型的研究工具，它主要用来降低全球地震和核爆破的检测阈值和研究地球内部结构。 相似文献
18.
19.
基于光子计数探测器的能谱CT,可以同时采集多个能谱通道的投影数据,并获得相应能量范围内物质的吸收特征,可以有效应用于物质识别与材料分解。主成分分析是一种很好的多元数据分析技术,可以用于处理多能谱CT数据。本文分别在投影域和图像域对能谱CT数据进行主成分分析,并对分析结果做出系统比较。为了减少噪声的影响,提高能谱CT图像的彩色表征性能,提出双域滤波与像素值平方相结合的方法,用于含噪声的主成分图像去噪,然后将所选取的主成分图像映射到RGB颜色通道。实验结果表明,无论是在投影域还是图像域进行主成分分析,都可以获取清晰的CT图像,识别出物质的不同成分。相较于在图像域的主成分分析方法,在投影域进行主成分分析能够保留物质的更多细节,获取更清晰的彩色CT图像。 相似文献
20.
Airborne Gradiometry Error Analysis 总被引：3，自引：0，他引：3
Christopher Jekeli 《Surveys in Geophysics》2006,27(2):257-275
Gravity gradiometry is one of the older methods of determining the Earth’s local gravitational field, but lies in the shadow
of more conventional static and moving-base gravimeter-based systems. While the static torsion balance appears to have been
relegated to the museum, support for the airborne and space-borne differential accelerometer (gradiometer) continues so as
to overcome limitations in spatial resolution and accuracy inherent in ordinary moving-base gravimetry. One airborne system
exists, building on 30 year old technology concepts, and new technologies (e.g., cold-atom interferometry) promise significant
improvements. Concomitant advances are required to measure accurately the angular velocity and angular acceleration of the
platform, which inseparably combine (in an absolute sense) with the Earth’s gravitational gradients. A numerical analysis
of instrument errors, with simulated aircraft dynamics, shows that navigation-grade gyros are just sufficient to account for
these effects in gradiometers with 1E/
sensitivity. More accurate instruments, with 0.1 E/
sensitivity, require commensurate sensitivity in the gyros, of the order of 0.01°/h/
= 1.5\times10−4 ° \
for typical survey aircraft dynamics. On the other hand, typical orientation errors in the platform, which are problematic
for vector gravimetry, are much less of a concern in gradiometry. They couple to the gradient signals and affect only the
very low frequencies of the total gradient error. 相似文献