Application of stress release models to historical earthquakes from North China

Univariate and multivariate stress release models are fitted to historical earthquake data from North China. It is shown that a better fit is obtained by treating separately the Eastern part of the region, including the North China Plain and Bohai Sea, and the Western part of the region, including the Ordos Plateau and its Eastern boundary. Further improvement is obtained by fitting the large events (M7.6) and smaller events in the Western region by different stress release models. The comparisons are made by computing the likelihoods of the fitted models and discounting the number of parameters used by Akaike's AIC criterion. The models are used to develop long-term risk scenarios for the East and West regions.     

山西地震综合数据处理系统

《山西地震综合数据处理系统》是遵循《国家地震局数据库技术规范》,以PDP-11/23~+小型机与IBM/PC联机为硬件支撑,以网状型数据库为核心,含前期处理、库管理、数据检索、科学计算、分析会商5个子系统的较大型应用软件系统。具有对数据进行收集、录入、预处理、存储、管理、加工及应用等功能。整个系统通过总控菜单程序实现了异种机间上百个模块的调度,使查询-处理一体化。该系统把地震数据库、日常监测数据处理、专家地震预报系统有机地衔接于一体,可直接服务于地震科研和震情会商。该系统的建设是山西省重大科技攻关项目,也是国家地震局的合同制项目。     

1966年邢台7.2级地震的构造背景和发震构造

本文根据石油地质勘探的最新资料和元-济人工地震地壳测深剖面相应地段重新解释的结果,分析了邢台7.2级地震的构造背景和发震断裂。研究结果表明,7.2级地震震中位于束鹿断陷盆地南部次凹的东缘,该次凹发育在由新河断裂等4条缓倾铲形正断裂分制围限地台盖层而成的“斛”状构造块体上,块体之下的地壳中存在两条倾向相反的高角度断裂;地震与断陷主断裂及其控制的断陷盆地并非是简单的对应关系,7.2级地震的发震断裂不是单一的缓倾铲形新河断裂或其下方的高角度的F_3断裂和深部的东断裂,而是它们的组合,且高角度断裂是发震断裂的主要部分     

Quaternary fault segmentation and interaction in the epicentral area of the 1561 earthquake (Mw = 6.4), Vallo di Diano, southern Apennines, Italy

The main structural characteristics of the Caggiano and Polla faults, exposed in the epicentral area of the 1561 earthquake (Mw = 6.4), southern Italy, have been investigated in detail to assess their spatial and temporal properties, and to evaluate their seismogenic potential. These right stepping normal faults show an overlap of about 7 km and an across strike separation of about 4 km. The geometric relationships between the Caggiano and Polla faults, but also the displacement distribution along each fault, demonstrate that they have been strongly interacting throughout the Pleistocene. Nevertheless, geological evidence of Holocene tectonic activity was mainly recognized along the Caggiano Fault (faulted late glacial deposits) and in the southernmost part of the Polla Fault (faulted deposits of probably Late Pleistocene age). This suggests that the Caggiano Fault can be considered as the most tectonically active fault in the Vallo di Diano Fault System. By calculating Coulomb stress changes, we have constrained modes of mechanical interactions between the two faults in a scenario compatible with the 1561 earthquake. This approach allows us to argue that both the Caggiano and the Polla Faults are probably linked at depth, and part of the same seismogenic structure which may be potentially responsible for composite ruptures with magnitude ≥ 6.5.     

内蒙阿右旗铁板井镍矿矿床特征及成因探讨

铁板井绦矿床赋存于辉橄岩体中,辉橄岩体具有全岩矿化的特点,岩体及镍矿体的形成经历了三种不同的成矿过程:首先是岩浆深源液态重力分异作用,而后发生岩浆深源熔离-贯入(成岩、成矿)作用,形成岩体和镍矿体,最后在岩浆期后热液作用的叠加下完成整个成矿过程.该矿床是典型的主要由岩浆熔离作用形成的岩浆矿床.     

Nonlinear Analysis of Local Site Effects on Seismic Ground Response in the Bam Earthquake

The influence of local geologic and soil conditions on the intensity of ground shaking is addressed in this study. The amplification of the ground motion due to local site effects resulted in severe damage to dwellings in the Bam area during the 2003 Bam Earthquake. A unique set of strong motion acceleration recordings was obtained at the Bam accelerograph station. Although the highest peak ground acceleration recorded was the vertical component (nearly 1 g), the longitudinal component (fault-parallel motion) clearly had the largest maximum velocity as well as maximum ground displacement. Subsurface geotechnical and geophysical (down-hole) data in two different sites have been obtained and used to estimate the local site condition on earthquake ground motion in the area. The ground response analyses have been conducted considering the nonlinear behavior of the soil deposits using both equivalent linear and nonlinear approaches. The fully nonlinear method embodied in FLAC was used to evaluate the nonlinear soil properties on earthquake wave propagation through the soil layer, and compare with the response from the equivalent linear approach. It is shown that thick alluvium deposits amplified the ground motion and resulted in significant damage in residential buildings in the earthquake stricken region. The comparison of results indicated similar response spectra of the motions for both equivalent and nonlinear analyses, showing peaks in the period range of 0.3–1.5 s. However, the amplification levels of nonlinear analysis were less than the equivalent linear method especially in long periods. The observed response spectra are shown to be above the NEHRP building code design requirements, especially at high frequencies.     

鲁中南隆起区第四纪晚期断裂活动特征

根据野外调查，并综合前人的研究资料，对鲁中南地区第四纪晚期断裂活动进行了分析，研究表明，鲁中南隆起区第四纪断裂活动具有时空不均匀性，主要表现为第四纪时期断层活动强度变化和断裂活动的群集性以及第四纪晚期断裂活动段分布的局限性上。对于鲁中南地区而言，活动断层可以分为中更新世中期（500kaBP)至晚更新世初期（90kaBP)活断层和晚更新世中、晚期至全新世早期活断层两类；其中前一类（主要是中更新世断裂）断裂数量较多，分布较为广泛，而晚更新世晚期以来的活动断裂段的数量较少，分布较局限。它们对地震的控制能力不同，前者可控制5．5级左右的地震，而后一类可控制6－7级地震的发生。     

Stability Design System of Submarine Pipelines

This paper introduces a stability design system of submarine pipelines. The system can provide a reasonable design procedure for users with reference to domestic and foreign methods and in the light of home engineering experience.     

台湾及其邻海的重力特征与构造、地震的关系

分析认为，在台湾及其邻海的重力场中，具有短波长特征的空间重力异常受地形与海深所制约．玉山的200×10     

海岛旅游效率空间格局演变及影响因素研究 ——以中国12个海岛县(区)为例

旅游产业是海岛地区的重要产业之一，借助 DEA 模型测度 12 个海岛县 （区） 的旅游效率，采用组合方法对海岛旅游效率的空间特征演变进行刻画，并通过 EVIEWS 软件分析海岛旅游效率的影响因素。 （1） 海岛旅游综合效率总体不高，技术效率是海岛旅游效率发展的主要驱动力，规模效率水平较低，海岛旅游发展能力未得到全面发挥。 （2） 海岛县 （区） 之间旅游效率总体差异不大，相对差异明显。海岛旅游效率空间状态演变由不稳定趋向于稳定，可能存在“贫困陷阱”和“俱乐部趋同”现象。 （3） 经济发展水平、生态环境、科技信息对海岛旅游效率的发展起到积极的推动作用，产业结构、交通条件、城镇化是海岛旅游效率发展的约束性因素。