Active fault database of Turkey

We have updated the active fault map of Turkey and built its database within GIS environment. In the study, four distinct active fault types, classified according to geochronological criteria and character, were delineated on the 1:25,000 base map of Turkey. 176 fault segments not included in the former active fault map of Turkey, have been identified and documented. We infer that there are 485 single fault segments which are substantially potential seismic sources. In total 1964 active-fault base-maps were transferred into the GIS environment. Each fault was attributed with key parameters such as class, activity, type, length, trend, and attitude of fault plane. The fault parameters are also supported by slip-rate and seismogenic depth inferred from available GPS, seismological and paleoseismological data. Additionally, expected maximum magnitude for each fault segment was estimated by empirical equations. We present the database in a parametric catalogue of fault segments to be of interest in earthquake engineering and seismotectonics. The study provides essential geological and seismological inputs for regional seismic hazard analysis of all over Turkey and its vicinity.     

唐山－河间－磁县新生地震构造带

地震构造研究往往注重那些形成历史长且规模较大的活动断裂带。实际上还存在一种与现代地质环境和区域应力状态基本保持一致的最近构造阶段新发育的断裂带，即新生断裂带。地震活动与这两种构造带关系密切。根据地震和地质构造等资料分析认为，唐山－河间－磁县地震带是一条晚第三纪开始发育的新生地震构造带。     

唐山－河间－磁县新生地震构造带

地震构造研究往往注重那些形成历史长且规模较大的活动断裂带。实际上还存在一种与现代地质环境和区域应力状态基本保持一致的最近构造阶段新发育的断裂带，即新生断裂带。地震活动与这两种构造带关系密切。根据地震和地质构造等资料分析认为，唐山－河间－磁县地震带是一条晚第三纪开始发育的新生地震构造带     

Seismic hazard model for loss estimation and risk management in Taiwan

We developed a seismic hazard model for Taiwan that integrates all available tectonic, seismicity, and seismic hazard information in the region to provide risk managers and engineers with a model they can use to estimate earthquake losses and manage seismic risk in Taiwan. The seismic hazard model is composed of two major components: a seismotectonic model and a ground-shaking model. The seismotectonic model incorporates earthquakes that are expected to occur on the Ryukyu and Manila subduction zones, on the intermediate-depth Wadati-Benioff seismicity zones, on the active crustal faults, and within seismotectonic provinces. The active crustal faults include the Chelungpu fault zone, the source of the damaging M_W 7.6 Chi-Chi earthquake, and the Huangchi-Hsiaoyukeng fault zone that forms the western boundary of the Taipei Basin. The ground-shaking model uses both US, worldwide, and Taiwanese attenuation relations to provide robust estimates of peak ground acceleration and response spectral acceleration on a reference site condition for shallow crustal and subduction zone earthquakes. The ground shaking for other site conditions is obtained by applying a nonlinear soil-amplification factor defined in terms of the average shear-wave velocity in the top 30 m of the soil profile, consistent with the methodology used in the current US and proposed Taiwan building codes.     

Characterizing the active tectonics in the Oran region (Algeria) and recasting the 1790 earthquake

In this work, we reappraise the seismogenic potential of the geologic structures in the western Tell Atlas of Algeria, considered active host to moderate to low magnitude earthquakes. The direct identification of active faults is generally a difficult task in northern Algeria. The active tectonics in the Oran Plio-Quaternary age basin (Northwestern Algeria) is analyzed and characterized through a morpho-structural study combining topographic, geomorphologic, geological, and neotectonic data. Folds and fault scarps affecting Quaternary deposits show that the region is affected by compressional deformation still active nowadays, as shown by the recorded seismic activity. Our new observations enable a better understanding of the present seismotectonic context of the Oran region, particularly with regard to the magnitude and source of the 1790 Oran damaging event. The obtained result helps to shed some light on the elusive active tectonics characterizing this coastal area, and to assess regional seismic hazard, particularly in coastal zones where large seismogenic areas straddle the onshore–offshore zones.     

Seismic Ground Motion Zoning Maps of the Pangxi Region

The seismotectonic environment and seismic activity in Southwest China region were studied based on new data and new results obtained during the Eighth and Ninth Five-Year Plans,the seismic areas and zones and potential seismic source zones were determined.and the relation between seismic activity parameters and ground motion attenuation was determined.Finally the seismic gound motion zoning maps of the Pangxi region was compiled by using the multi-parameter and multi-scheme method.     

Seismic source characterization for the Shillong Plateau in Northeast India

The present study aims at understanding the seismotectonic province of the Shillong Plateau (SP) by identifying the potential seismic source zones within a radius of 500 km from the centre of the SP. From existing literature and earthquake (EQ) data, the seismotectonic region is found to vary in terms of seismicity, tectonic features, geology, thickness of overburden, rupture characteristics and rate of movement. Thus, entire 500-km-radius seismotectonic region is divided into four seismic source zones: namely (1) the Shillong Plateau–Assam Valley Zone (SP-AVZ), (2) the Indo-Burma Ranges Zone (IBRZ), (3) the Bengal Basin Zone (BBZ) and (4) the Eastern Himalaya Zone (EHZ). EQ catalogues for each source zone is analysed for completeness of magnitude and time. Seismic parameter b estimated using a maximum likelihood method is found to be 0.91 ± 0.03, 0.94 ± 0.02, 0.80 ± 0.03 and 0.89 ± 0.03 for the SP-AVZ, IBRZ, BBZ and EHZ, respectively. In addition, the maximum likelihood method is used to estimate the mean annual activity rate, maximum possible magnitude (m _max), return period and probability of exceedance for the four zones. The b values estimated suggest that the BBZ is seismically more active; however, the rate of occurrence of EQs is highest in the IBRZ. Findings from this study are an indication of the relative contribution from each of the four seismic source zones towards a seismic hazard of the SP.     

Discussion on Characteristics of Crustal Deformation along the Zhangjiakou-Bohai Sea Seismotectonic Zone

INTRODUCTIONThe Zhangjiakou-Penglai fault zone has drawnextensive attentionfromseismologists and geologistssince it was determinedinthe1980’s(Zheng Binghua,et al.,1981).Ma Xingyuan,et al.(1989)consideredit asthe north boundaryof North China sub-block.Int…     

Seismotectonic Model and CN Earthquake Prediction in Italy

—The choice of the regions is essential in the application of the algorithm CN, therefore a seismotectonic criterion for their definition is tested. In order to take into account the geodynamic complexity characterising the Italian peninsula, we established to strictly follow the seismotectonic zones, including in each region only zones with similar seismogenic behaviour and the transitional zones connected to them. Three regions have been successfully defined in this way, corresponding approximately to the North, Centre and South of Italy. The reduction of the space-time uncertainty and the increase of the stability of prediction results obtained with this regionalisation, with respect to the previous applications of CN in Italy (Keilis-Borok et al., 1990; Costa et al., 1995, 1996), can be interpreted as a validation of the seismotectonic model.     

西南地区区域地震构造图数据库

利用西南地区多年来积累的地震安全性评价工作成果,借助地理信息系统MapInfo强大的空间信息表达能力,使在MapInfo平台上构建西南地区区域地震构造图数据库成为可能。文中使用空间数据库与属性数据库分开设计的方法,采用多个层次、多种基本类型、多表关联的数据库格式,在MapInfo平台上构建了西南地区区域地震构造图数据库     

Preliminary Study on Two Newly-Generated Seismotectonic Zones in North and Southwest China

In previous seismotectonic studies,the emphasis was placed on the inherited active fault zones.In the recent tectonic stage that essentially keeps in step with the current regional geologic environment and the stress field,however,there are also some newly generated fault zones.By studying the seismicity in North and Southwest China,it has been known that the NE-trending Tangshan-Hejian-Cixian and NW-trending Tengchong-Gengma-Lancang seismic zones are just two newly generated fault zones.As distinguished from the inherited fault zones,they are called the newly generated seismotectonic zones.This paper deals with the existence of these two seismogenic zones from their seismicity and geological structures,gives a preliminary analysis of their characteristics,and shows their significance.     

我国华北和西南地区两条新生地震构造带的初步研究

在以往的地震构造研究中,注重了那些继承活动的断裂带．但在与现今区域地质环境和应力场性质基本保持一致的最近构造阶段,还有正在产生的新断裂带,即新生断裂带．我国华北和西南地区由地震活动揭示出的北东向唐山－河间－磁县和北西向腾冲－耿马－澜沧两条地震带,对应的正是新生断裂带．为示区别,称其为新生地震构造带．以这两条地震构造带为例,从地震活动和地质构造方面论证它们的存在,初步分析它们的特征和研究意义．     

Seismic hazard in the Northwestern Apennines

A study of the seismic hazard for the Northwestern Apennines, based on seismotectonic and seismicity data, is presented. Starting from a seismotectonic analysis, showing the complex structural evolution of the region, the seismic activity in the period 1000–1975 has been modeled by some seismic source zones justified by geostructural and seismological considerations. The recurrence statistical parameters and the attenuation laws have been determined for all these sources. With an appropriate analysis method, maps of seismic hazard for return periods of 50, 200, and 500 years were elaborated. Finally, a comparison with the map of maximum felt intensity and with hazard values calculated by a different approach is presented.     

龙门山和成都地震构造区的划分

新编制的地震动参数区划图采用了潜在震源区三级划分方案,以体现背景地震活动空间分布的不均匀性,并在地震构造区内归纳出统一的地震构造模型。本文根据西南地区潜在震源区三级划分的成果,分析了龙门山地震统计区内的龙门山和成都地震构造区的基本特征,历史地震活动强度及频度,主要活动构造的构造变形样式,建立了地震构造区的发震构造模型,确定了构造区的本地地震及划分构造源的地震构造标志。同时,提出了确定背景源空间分布函数的简单方法。     

华北地区的共轭地震构造带

本文采用小地震活动图象和４．０级（Ｍｓ）以上地震震源机制资料的构造分析方法，得到一幅华北地区震源构造在地面的投影分布图，它显示４条ＮＮＥ－ＮＥ向和１条ＮＷＷ－ＮＷ向地震构造带交切成的共轭剪切构造格架。每条地震构造带又由一系列共轭剪切构造组成。由发生在带内的５个大震序列共轭破裂特征发现，共轭地震构造的孕震与控震作用是地震构造带形成的机制。     

基于ArcGIS的1:80万吉林省地震构造图绘制技术

利用ArcGIS平台完成1:80万吉林省地震构造图绘制工作,由此表述专业图件的一般绘制过程与主要技术手段.对其项目的一般绘制过程,包括组织实施方式、原始资料规范化、图件的专业分层做简要说明.对绘制过程中的技术难点、技术手段,如:地理信息数据库的建立、数据导人、图像矢量化、空间归并、符号化等关键技术,做深人探讨.文中介绍...     

基于GeoDatabase的地震构造背景场数据库设计与实现

在介绍GeoDatabase基本结构的基础上,阐述了以个人版GeoDatabase数据模型为基础的云南省地震构造背景场数据库的设计方法实现过程.该数据库建立后能够有效管理多源地震专业数据,可满足地震构造背景数据的一体化管理的需要,并为今后地震构造领域的信息化建设提供了一定的科学依据.     

面状发震构造在地震构造法中的应用：以大姚—姚安发震构造鉴定为例

核电厂地震安全性评价中的地震构造法,要求鉴定发震构造和划分地震构造区,在以往实践中,发震构造鉴定往往基于地表活动断裂构造,且表征为线状震源.当存在较强非随机分布的地震活动且难以找到清晰的地表活动断裂构造形迹时,地震构造法就难以合理地表现这些地震的危险性.本文以云南滇中大姚—姚安发震构造鉴定为例,探讨了在地表活动构造形迹不清,中强地震活动性较强的滇中大姚—姚安地区,采用面状发震构造来表征地震危险性的方法,讨论了在地震构造法中采用面状发震构造的必要性、鉴定思路和方法,并建议在今后的核工程地震危险性评价地震构造法中应充分考虑面状发震构造的应用.     

龙门山和成都地震构造区的划分

新编制的地震动参数区划图采用了潜在震源区三级划分方案,以体现背景地震活动空间分布的不均匀性,并在地震构造区内归纳出统一的地震构造模型.本文根据西南地区潜在震源区三级划分的成果,分析了龙门山地震统计区内的龙门山和成都地震构造区的基本特征,历史地震活动强度及频度,主要活动构造的构造变形样式,建立了地震构造区的发震构造模型,确定了构造区的本底地震及划分构造源的地震构造标志.同时,提出了确定背景源空间分布函数的简单方法.     

design and construction of national active fault data integration and sharing platform

Over the past nearly 20 years, there is a huge development in active fault database related technologies in China, mass of active fault data has provided us important basis for researching on earthquake and disaster reduction, etc. However, with the appearance of huge amount of active fault data, lots of problems have emerged, such as data redundancy, inefficient management and information islands, etc. One of the major reasons is lack of efficient method to share the active fault data we owned.By study and comparison, we find that WebGIS is a good solution to solve the problem of active fault data publishing and sharing. WebGIS has well combined the advantages of traditional GIS and internet technologies, it could also share geographic data quickly, provide abundant browsing, searching and analysis functions. Based on the project of "China Earthquake Active Fault Detection—The North China Tectonic Region", and taking the foundational database information sharing platform of the active fault detection and survey as an example, the paper introduces the key technologies of active fault data sharing platform with latest WebGIS technology. The sharing system, which employs ArcGIS Server 10.0 as the GIS server, and utilizes MS-Silverlight technology at the client side, makes use of three-layer architecture which is popular in current B/S mode. To guarantee the security of the database on the internet, data source in the backend of the system is a simplified version of the active fault database of the North China tectonic region. Finally, the system has realized the publishing and sharing of 1 ︰ 50000 active fault mapping and main geophysical survey lines in North China tectonic region, and moreover, it provides some conventional map operations as well as fault searching and locating functions.The wide use of active fault data decides the significance of sharing system. It is very convenient to use this lightweight data sharing system to provide important basis for relevant industries, such as urban planning, land use and engineering site option, etc.