Probabilistic seismic hazard maps for Panama

Probabilistic seismic hazard maps in term of Modified Mercalli (MM) intensity are derived by applying the Cornell-McGuire method to four earthquake source zones in Panama and adjacent areas. The maps contain estimates of the maximum MM intensity for return periods of 5, 25 and 100 yr. The earthquake phenomenon is based on the point source model. The probabilistic iso-intensity map for a return period of 50 yr indicates that the Panama Suture Zone (PSZ) could experience a maximum (MM) intensity IX, and the Panama Fracture Zone (PFZ) an MM intensity VIII, for the rest of the area this varies from IV up to VIII. The present study intends to serve as a reference for more advanced approaches, to stimulate discussions and suggestions on the data base, assumptions and inputs, and path for the risk based assessment of the seismic hazard in the site selection and in the design of common buildings and engineering.     

Probabilistic seismic hazard zonation of Syria

Earthquake hazard maps for Syria are presented in this paper. The Peak Ground Acceleration (PGA) and the Modified Mercalli Intensity (MMI) on bedrock, both with 90% probability of not being exceeded during a life time of 50, 100 and 200 years, respectively are developed. The probabilistic PGA and MMI values are evaluated assuming linear sources (faults) as potential sources of future earthquakes. A new attenuation relationship for this region is developed. Ten distinctive faults of potential earthquakes are identified in and around Syria. The pertinent parameters of each fault, such as theb-parameter in the Gutenberg-Richter formula, the annual rate ₄ and the upper bound magnitudem ₁ are determined from two sets of seismic data: the historical earthquakes and the instrumentally recorded earthquake data (AD 1900–1992). The seismic hazard maps developed are intended for preliminary analysis of new designs and seismic check of existing civil engineering structures.     

Some aspects of the seismic hazard in Panama City

The definition of earthquake sources in the Panama region on the basis of both tectonics and average seismicity rates, have recently led to the concept of a microplate surrounded by seismically active areas. The effects of these earthquakes on the place where the most important concentration of investments and population is located, the capital city of Panama, are analyzed in this paper using statistical approaches.The parameters of Gumbel's Type-I distribution of extreme values for a continuous interval of 60 yr annual maximum magnitudes were used to make probabilistic estimations of the seismic hazard in Panama City. An earthquake with magnitude 7.5 is capable of producing a modified Mercalli intensity VII in Panama City, provided the source distance is of the order of 100 km. This earthquake has a probability of occurrence of 69% in 50 yr.     

基于震害统计的城市地下空间地震安全性评价

建筑物的地震安全性是城市规划和建设过程首先要回答的问题。我国城市地震安全性评价的方法理论多针对地上建筑物,而对地下空间的地震安全性研究较为薄弱,严重滞后于城市发展对地下空间的需求。活断层是诱发地震、导致建筑物破坏的的直接因素。考虑到空间关系上,地下空间与断层之间的交互关系为相交或相离。因此,本文将地下空间分为两类:与断层相交的地下空间称为跨断层地下空间,远离断层的地下空间称为远离断层地下空间。本文尝试将断裂带同震地表破裂、地震峰值加速度、地震烈度等地表地震安全性评价考量的要素与地下空间埋藏深度建立联系,并在此基础上总结基于震害统计的地下空间地震安全性评价方法。最后,本文选取地下空间利用需求较高的深圳和北京地区为实例进行介绍。     

Probabilistic assessment of seismic hazard of dam sites in Jordan

A Probabilistic method is used to evaluate the seismic hazard of nineteen embankment dam sites in Jordan. A line source model developed by McGuire (1978) is used in this study. An updated earthquake catalogue covering the period from 1 A.D. to 1991 A.D. is used for this purpose. This catalogue includes all earthquakes that occurred in Jordan and adjacent areas, more specifically between latitudes 27.0°–35.5° N and longitudes 32.0°–39.0° E.Nine distinct seismic sources of potential seismic activities are identified. The seismic hazard parameters are determined using the method suggested by Kijko and Sellevoll (1989).The Peak Ground Acceleration (PGA) is selected as a measure of ground motion severity. Esteva (1974) attenuation relationship is used in evaluating PGA values at each dam site. Analysis is carried out for 50%, 90%, and 95% probability that is not being exceeded in a life time of 50, 100, and 200 years.Results of analysis indicate that PGA values are higher for dam sites closer to the Dead Sea Fault. This fault is believed to be responsible for most earthquake activities in Jordan and vicinity. The highest PGA value is found to be for Al-Karama dam site.     

Influence of attenuation models in seismic hazard evaluation for the North-Eastern Sicily area

From the influence already revealed by attenuation models on the values of expected intensity for North-Eastern Sicily, the necessity arises to quantify the weight of these models and of their respective coefficients on the projection of intensity.A first evaluation is presented in this paper using the Sponheuer, Blake, and Grandori models.A comparison of the expected intensity maps allows a first critical estimate, showing the greater adaptability of the Grandori model to describe the attenuation of intensity for the investigated area.     

煤矿井下地震勘探资料特殊处理方法及效果

与地面地震勘探相比,煤矿井下地震勘探具有较高的分辨率,但也存在一些特殊问题,如炮间时差即为其一,需要采取特殊处理手段加以解决。针对矿用雷管引起的各炮间时差问题,采用单炮初至时间回归预测分析方法校正激发时间不一致所带来的延迟时,并引入了地表一致性振幅校正及地表一致性反褶积技术,使得煤矿井下地震信号振幅、波形不一致的问题得到了较大的改善。实际资料处理效果表明：经过以上处理后,煤矿井下地震叠加剖面效果得到明显改善,为构造解释和岩性解释创造了条件。     

Probabilistic seismic hazard assessment for the Horn of Africa based on seismotectonic regionalisation

A probabilistic seismic hazard analysis (PSHA) for the Horn of Africa is presented. Our seismicity database consists of a revised and up-to-date regional catalogue compiled from different agencies, checked for completeness with respect to time and homogenized with respect to magnitude (M_s). The seismic source zones are based on our present day knowledge of the regional seismotectonics. Among the results we present regional hazard maps for 0.01 annual probability for intensity and Peak Ground Acceleration (PGA) and hazard curves and response spectra for six economical significant sites within the region. The model uncertainties with respect to seismicity are analysed in a novel approach and form part of a sensitivity analysis that quantifies our PSHA modelling uncertainties.

For 0.01 annual probability we find randomly oriented horizontal PGA that exceed just 0.2 g and MM-scale intensity VIII in the Afar depression and southern Sudan. Uncertainties amount to 20% g PGA in some cases, mainly due to attenuation uncertainties. Intensity uncertainties seldom exceed 0.5 intensity units. Relatively large seismic hazard is found for Djibouti (VIII for 0.01 annual probability), slightly lower for the port of Massawa (between VII and VIII for 0.01 annual probability) and low for the port of Assab (between VI and VII for 0.01 annual probability).     

Preliminary seismic hazard maps of Slovenia

The preparation of the preliminary seismic hazard maps of the territory of Slovenia has been based on an expansion of the basic approach laid out by Cornell in 1968. Three seismic source models were prepared. Two of them are based mainly on the earthquake catalogue using the Poissonian probability model. A map of seismic energy release and a map of earthquake epicenter density are used to delineate seismic sources in these models. The geometry of the third model which is based on a rough estimate of seismotectonic setting is taken from the probabilistic seismic hazard analysis of a nuclear power plant in Slovenia. Published ground motion attenuation models based on strong motion records of recent strong earthquakes in Italy are used. Test maps for variable and uniform b-values are presented. The computer program, Seisrisk III, developed by the U.S. Geological Survey is used.     

地震危险性、地震危害性和地震易损性

做好城市防震减灾工作 ,关键是对未来可能遭遇地震灾害定量化预测。本文论述地震灾害定量化的三要素 :地震危险性 ,地震危害性和地震易损性 ,它们概念完全不同 ,且很容易混淆 ,但又存在因与果的关系。本文还简要介绍厦门市地震科技工作者开展的“闽南地区综合防震减灾示范工程”。     

煤矿井下保直钻进技术现状及展望

煤矿井下钻孔轨迹偏斜易导致治理盲区的出现,严重威胁煤矿安全高效开采。通过对导致钻孔偏斜的地质因素、技术因素和工艺因素的系统分析,得到了钻孔偏斜的根本原因。对现有保直技术的原理及其适用性进行了分析总结。钻孔保直是影响钻孔施工质量的因素,但目前钻孔保直技术或多或少都存在技术上的问题,不能在煤矿大范围推广使用,故在钻孔保直方面需要不断发展,研发出适用性强、易于现场实施的保直技术。应加强偏斜因素的深层次的研究、钻孔保直机具设备的研发等工作。     

Seismic hazard maps for the U.K.

Past studies of seismic hazard in the U.K. that have used modern probabilistic methods of hazard assessment have been site-specific studies, mostly in connection with nuclear installations. There has been a need for general-purpose maps of seismic hazard to show relative variation of exposure within the U.K. and to give some guidance on absolute values. Such maps have now been produced, incorporating, for the first time, the wealth of new information on historical earthquakes in Britain that has been gathered over the last 15 years. The hazard calculations were undertaken using a new computer code based on the USGS program SEISRISK III, but incorporating a logic tree approach to model variation in the input parameters (e.g. focal depth) or uncertainty in the formulation of the model (e.g. attenuation parameters). An innovative approach was taken to the formulation of seismic source zones, in which two overlapping models were employed. The first of these uses relatively broad source zones based loosely on an interpretation of seismicity and tectonics, while the second uses numerous small zones that reflect the locations of past significant earthquakes. This double approach (using the logic tree methodology) has the merit of both considering the general trend of earthquake activity as well as focusing in on known danger spots. The results show that the areas of highest hazard are western Scotland, north-western England and Wales, where the intensity with 90% probability of non-exceedance in 50 years is 6 EMS.     

Probabilistic seismic hazard analysis for Bangalore

This article presents the results of probabilistic seismic hazard analysis (PSHA) for Bangalore, South India. Analyses have been carried out considering the seismotectonic parameters of the region covering a radius of 350 km keeping Bangalore as the center. Seismic hazard parameter ‘b’ has been evaluated considering the available earthquake data using (1) Gutenberg–Richter (G–R) relationship and (2) Kijko and Sellevoll (1989, 1992) method utilizing extreme and complete catalogs. The ‘b’ parameter was estimated to be 0.62 to 0.98 from G–R relation and 0.87 ± 0.03 from Kijko and Sellevoll method. The results obtained are a little higher than the ‘b’ values published earlier for southern India. Further, probabilistic seismic hazard analysis for Bangalore region has been carried out considering six seismogenic sources. From the analysis, mean annual rate of exceedance and cumulative probability hazard curve for peak ground acceleration (PGA) and spectral acceleration (Sa) have been generated. The quantified hazard values in terms of the rock level peak ground acceleration (PGA) are mapped for 10% probability of exceedance in 50 years on a grid size of 0.5 km × 0.5 km. In addition, Uniform Hazard Response Spectrum (UHRS) at rock level is also developed for the 5% damping corresponding to 10% probability of exceedance in 50 years. The peak ground acceleration (PGA) value of 0.121 g obtained from the present investigation is slightly lower (but comparable) than the PGA values obtained from the deterministic seismic hazard analysis (DSHA) for the same area. However, the PGA value obtained in the current investigation is higher than PGA values reported in the global seismic hazard assessment program (GSHAP) maps of Bhatia et al. (1999) for the shield area.     

Comparison of two methods for seismic hazard assessment in a low-seismicity area

The EGO method, developed by Egozcue et al. and the SRAMSC method, originally developed by Cornell and later programmed by McGuire, to assess the seismic hazard, are compared for the low seismicity area Belgium, The Netherlands, and NW Germany. Using the same input data, the results of the EGO method without the majority criterion and the SRAMSC method with upper bound XII agree very well. The influence of the zoning is investigated for the EGO method. It is not necessary to define the zones for the EGO method so strictly as for the SRAMSC method, but too wide zones can give bad results.     

Estimation of seismic hazard parameters in TERESA test areas

A general overview of some of the problems involved in earthquake catalogue handling is given as part of the works carried out into the ESC/SC8-TERESA project related with the seismic hazard assessment in two selected test areas: Sannio-Matese in Italy and the northern Rhine region (BGN). Furthermore, the necessary input data to be used in the calculation of seismic hazard has been obtained, including earthquake source zones and their seismic hazard parameters.The importance is pointed out of detailed analysis of seismic catalogues, mainly in relation to the use of aftershock information, the historical records of the region, and the possible temporal and spatial variation of seismicity, which could have an important influence on short-term hazard assessment.     

Pathways to seismic hazard evaluation: Extreme and characteristic earthquakes in areas of low and high seismicity

The general philosophy of seismic hazard evaluation described here is appropriate for selection of seismic input to regional earthquake engineering codes prior to detailed on-site inspections and geotechnical assessments. Some probabilistic seismic hazard methodologies which can be applied in areas of low and high seismicity, are briefly described to emphasise the main equations with specimen results. Three aspects of hazard assessment are explored by different pathways. These include the analysis of regional earthquake catalogues to obtain magnitude recurrence, particularly using Gumbel extreme value statistics. This is extended to assess ground shaking hazard which is usually sought by earthquake engineers. Thirdly, the concept of earthquake perceptibility is developed, leading to the identification of an earthquake magnitude or type which is characteristic of a region. This most perceptible earthquake is most likely to be felt at any site in a region and provides an earthquake selection criterion which can be used in aseismic design of noncritical structures. Because there are several methods of seismic hazard evaluation, the view is expressed that it is sensible for practical purposes to seek results from different methods or different pathways to the hazard evaluation.Paper presented at the Commission of the European Communities' School on Earthquake Hazard Evaluation, Athens, and at the 21st General Assembly of the European Seismological Commission, held in Sofia, 1988.Now at School of Environmental Sciences, University of East Anglia, University Plain, Norwich NR4 7TJ, U.K.     

Probabilistic seismic and tsunami hazard analysis for design criteria development of a coastal area in the city of Banda Aceh

Both seismic and tsunami hazards design criteria are essential input to the rehabilitation and long-term development of city of Banda Aceh Post Sumatra 2004 (M _w=9.3) disaster. A case study to develop design criteria for future disaster mitigation of the area is presented. The pilot study consists of probabilistic seismic and tsunami hazard analysis. Results of the probabilistic seismic hazard analysis indicates that peak ground acceleration at baserock for 10 and 2% probability of exceedance in 50 years is 0.3 and 0.55 g, respectively. The analysis also provides spectral values at short (T=0.2 s) and long period (T=1.0 s) motions. Some non-linear time-domain earthquake response analyses for soft, medium, and hard site-class were conducted to recommend design response spectra for each site-class. In addition, tsunami inundation maps generated from probabilistic tsunami hazard analysis were developed through tsunami wave propagation analysis and run-up numerical modeling associated with its probability of tsunamigenic earthquake source potential. Both the seismic and tsunami hazard curve and design criteria are recommended as contribution of this study for design criteria, as part of the disaster mitigation effort in the development process of the city. The methodology developed herein could be applied to other seismic and tsunami disaster potential areas.     

煤矿井下随掘地震震源特征及探测性能研究

煤矿智能化背景下,随掘地震已经成为掘进工作面安全掘进的地质保障关键技术之一,可实时、超前、精细探明掘进前方的隐蔽地质构造,如采空区、断层、陷落柱等,有效促进掘进生产安全高效。不同于广泛采用的反射槽波超前探测技术,随掘地震采用了掘进机掘进时震动信号作为激发源,替代了常规地震勘探中的炸药震源,具有震源绿色、安全、成本低、可重复、探掘同步等优点。由于掘进机震源在激发方式、能量、频率、带宽等方面与炸药震源差别较大,因此其探测性能受到很多关注。从随掘地震的震源机制、波场特征、传播距离、成像准确率等方面进行研究,详细分析其探测性能,认为随掘地震波场中槽波和横波发育,可利用槽波或横波进行超前探测;Y分量具有更好的信噪比优势,但在实际应用时考虑到反射面的走向,相同设备量情况下,Z分量更有优势;随掘地震的直达横波传播距离可达700 m以上,横波超前探测距离可达到300 m以上;随掘地震的直达槽波传播距离可达400 m 以上,槽波超前探测距离可达到170 m以上;常规掘进速度下,反射波叠加次数可达到16次,相比常规的一次探测,信噪比可提升4倍,有效提高了探测精度和准确度。后续将通过大量的随掘应用数据进一步修正随掘地震技术的性能参数。      

The importance of paleoseismology in seismic hazard studies for critical facilities

This paper is intended to provide a perspective on the use of paleoseismological studies in the seismic hazard assessment of critical facilities, such as dams, chemical/petrochemical facilities and nuclear power plants. In particular, the use of data obtained from paleoseismological studies for probabilistic seismic hazard analyses, when the required probabilities of exceedance are very low (e.g. 10^{− 6}–10^{− 7}) is considered. Recent revisions to the IAEA Safety Standards that provide guidance to Member States in their work related to the seismic safety of nuclear power plants are presented to illustrate the importance of this emerging discipline.     

煤矿井下智能化钻探装备发展现状及展望

经过近60年的发展,煤矿坑道钻探装备已经形成满足多种用途、适用于多种钻进孔深要求的多规格、多系列产品,但现有成熟钻探装备主要以全液压驱动和人工操作为主。随着我国煤矿企业在智能化方面建设的大力投入,传统全液压驱动的坑道钻探装备已无法满足当前煤矿智能化发展需要。结合坑道钻探的施工特点,分析了国外典型坑道钻探装备的技术现状和功能特点,以及存在的问题,重点针对国内坑道钻探装备不同施工需求的智能化方面的进展情况进行概述,分别介绍了常规自动化钻机、钻孔机器人、大功率自动化定向钻机、自动化防冲击钻机等方面的研究进展,提出了我国煤矿井下钻探装备智能化建设方面还需解决的关键问题,并通过分步实施方式,加快推进煤矿井下钻探装备的智能化水平。