哈萨克斯坦境内地震危险性评定的科学基础和方法

12.1地震危险性评定的概念性理论基础科学问题的解决意味着认知研究对象实际资料合理方法学的利用。因为,实际地质介质状态决定于有一定关系的不同规模构造单元的总体,并利用系统方法对它与地震关系进行研究。系统(主要对象)分成亚系统(高级对象)应由系统(主要对象)内部性质所决定。物质成分(间隙)、物体结构(构造)和作用动作(运动、演变、自然界所有过程和效应的普遍因果关系——决定论原理)是决定自然对象(宇宙)物质统一性的基本性质,对于自然对象可以认为,所有各个现象、事物、事件的原因在于这些现象、事物、事件之间的相互作用。因为,…     

第14章地震过程破坏后果预测的科学原理和方法

14．1关于地震后果 哈萨克斯坦地区广阔,它包括西哈萨克斯坦、克孜勒奥尔达、南哈萨克斯坦、江布尔、阿拉木图和东哈萨克斯坦（州）,这些地区都属于地震危险区域。地震最活动地区是天山、准噶尔阿拉套、塔尔巴哈台和阿尔泰造山作用地区。在19世纪末和20世纪初,仅天山地区就发生了数次破坏性地震,其中韦尔诺耶、奇利克和克明地震列入世界灾难性地震。这些地震的烈度为8—11度,地震导致人员死亡,建筑物破坏。     

第13章地震预报的科学基础和方法

地震动力学过程最强烈地发生于活动不均匀层范围内,从地震学观点来看,位错过程扩展具有本质意义,其含义就是断块沿“原始”断裂或构造层之间的界面位移。     

第1章地震过程理论基础

1．1概述 地震预报属于预报事件发生地点、强度和时间问题，实际上也是现代地球动力学问题。如果熟知了认识地球动力学过程物理本质的方法学，那么，预报问题是可以解决的。     

Probabilistic earthquake hazard assessment for Peninsular India

In this paper, a new probabilistic seismic hazard assessment (PSHA) is presented for Peninsular India. The PSHA has been performed using three different recurrence models: a classical seismic zonation model, a fault model, and a grid model. The development of a grid model based on a non-parameterized recurrence model using an adaptation of the Kernel-based method that has not been applied to this region before. The results obtained from the three models have been combined in a logic tree structure in order to investigate the impact of different weights of the models. Three suitable attenuation relations have been considered in terms of spectral acceleration for the stable continental crust as well as for the active crust within the Gujarat region. While Peninsular India has experienced large earthquakes, e.g., Latur and Jabalpur, it represents in general a stable continental region with little earthquake activity, as also confirmed in our hazard results. On the other hand, our study demonstrates that both the Gujarat and the Koyna regions are exposed to a high seismic hazard. The peak ground acceleration for 10 % exceedance in 50 years observed in Koyna is 0.4 g and in the Kutch region of Gujarat up to 0.3 g. With respect to spectral acceleration at 1 Hz, estimated ground motion amplitudes are higher in Gujarat than in the Koyna region due to the higher frequency of occurrence of larger earthquakes. We discuss the higher PGA levels for Koyna compared Gujarat and do not accept them uncritically.     

Rapid earthquake hazard and loss assessment for Euro-Mediterranean region

The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled “Network of Research Infra-structures for European Seismology, NERIES”. This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships.     

Seismic hazard assessment for derivation of earthquake scenarios in Risk-UE

The main features of the Risk-UE project approach to assessing the ground-shaking (and related hazards) distribution within urban areas are described, as a basis for developing seismic damage scenarios for European cities. Emphasis was placed in the project on adoption of homogeneous criteria in the quantitative treatment of seismicity and in constructing the ground-shaking scenarios, despite wide differences in amount and quality of data available for the cities involved. The initial steps of the approach include treatment of the regional seismotectonic setting and the geotechnical zonation of the urban area, while the hazard assessment itself takes the form of both a deterministic analysis, and of a probabilistic, constant-hazard spectra analysis. Systematic 1D site response analyses were used, mostly in the softer soil zones, to modify (when needed) the obtained ground motion maps. Earthquake induced hazard effects, such as liquefaction and landsliding, are also briefly dealt with at the end.     

The 1990 Zaisang earthquake of magnitude 7.3 in Kazakstan

The Zaisang earthquake (M _s=7.3) on June 14, 1990 occurred in the boundary between China and Kazakstan. During the great shock, 3 persons lost their lives, 30 people had been hurt and 340 houses collapsed. The intensity of the epicentre is VIII Degree. The economic losses equals to about 320 000 000 Yuan. This large earthquake was occurred on a new born fault, it belongs to main shock-aftershock type earthquake. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 360–365, 1993.     

Seismogenic potential and earthquake hazard assessment in the Tell Atlas of Algeria

Seismotectonic zonation studies in the Tell Atlas of Algeria, a branch of the Africa-Eurasia plate boundary, provide a valuable input for deterministic seismic hazard calculations. We delineate a number of seismogenic zones from causal relationships established between geological structures and earthquakes and compile a working seismic catalogue mainly from readily available sources. To this catalogue, for a most rational and best-justified hazard analysis, we add estimates of earthquake size translated from active faulting characteristics. We assess the regional seismic hazard using a deterministic procedure based on the computation of complete synthetic seismograms (up to 1 Hz) by the modal summation technique. As a result, we generate seismic hazard maps of maximum velocity, maximum displacement, and design ground acceleration that blend information from geology, historical seismicity and observational seismology, leading to better estimates of the earthquake hazard throughout northern Algeria. Our analysis and the resulting maps illustrate how different the estimate of seismic hazard is based primarily on combined geologic and seismological data with respect to the one for which only information from earthquake catalogues has been used.     

Considering potential seismic sources in earthquake hazard assessment for Northern Iran

Located on the Alpine-Himalayan earthquake belt, Iran is one of the seismically active regions of the world. Northern Iran, south of Caspian Basin, a hazardous subduction zone, is a densely populated and developing area of the country. Historical and instrumental documented seismicity indicates the occurrence of severe earthquakes leading to many deaths and large losses in the region. With growth of seismological and tectonic data, updated seismic hazard assessment is a worthwhile issue in emergency management programs and long-term developing plans in urban and rural areas of this region. In the present study, being armed with up-to-date information required for seismic hazard assessment including geological data and active tectonic setting for thorough investigation of the active and potential seismogenic sources, and historical and instrumental events for compiling the earthquake catalogue, probabilistic seismic hazard assessment is carried out for the region using three recent ground motion prediction equations. The logic tree method is utilized to capture epistemic uncertainty of the seismic hazard assessment in delineation of the seismic sources and selection of attenuation relations. The results are compared to a recent practice in code-prescribed seismic hazard of the region and are discussed in detail to explore their variation in each branch of logic tree approach. Also, seismic hazard maps of peak ground acceleration in rock site for 475- and 2,475-year return periods are provided for the region.     

大陆内部长余震序列及其对地震风险评估的启示

板块构造学说的最有力的特征之一,是已知的板块运动让我们对板块边界未来大地震的发震位置和平均复发间隔有更清晰的认识。然而,板块构造学说却不能预测板块内的地震何时何地发生,因为理想的板块内部是不会变形的。因此,板块内部的地震风险评估过于依靠如下假设：从有限的历史记录中得到的小地震发震位置能够反映出连续变形的地区,而变形将诱发未来大地震[1]。然而,本文将要说明的是,最近许多这样的小地震很可能是几百年前发生过的大地震的余震。文中将给出一个简单的模型,并由此模型得出：余震序列的长度和断层加载速率呈反比关系。发生在缓慢变形的大陆内部的余震序列,其持续时间与在快速加载的板块边界所观测到的典型的10年尺度余震序列相比要长得多。因为这些预测与观测结果相符,所以将大陆内部地震看作稳态地震活动的一般做法高估了目前地震活跃地区的地震危险性,而低估了其他地区的地震风险。