渭河盆地中土层场地对地震动的放大作用   总被引：11，自引：1，他引：10       下载免费PDF全文

王海云 《地球物理学报》2011,54(1):137-150

土层场地对地震动的影响较大,建(构)筑物的选址及其抗震设防必须考虑土层场地的放大作用,以避免或减轻其震害.汶川地震中,布设在渭河盆地中的数字强震动台网共有27个台站(包括2个基岩台站和25个土层台站)获得良好的主震加速度时程.利用这些加速度时程,选择汤峪台做为参考场地,基于考虑几何衰减的传统谱比法分析研究了25个土层场...  相似文献   

新疆乌恰5.1级地震强震动记录及震中区烈度考察对比分析     

何金刚  史勇军  吴国栋  胡伟华 《内陆地震》2011,25(3):247-254

2011年1月1日新疆乌恰县西南发生MS 5.1地震,新疆强震动台网布设在震中附近的10个强震动固定台获取了这次地震完整的加速度记录,记录的最大加速度为80.08 cm.s-2。对10个强震动台的加速度记录进行了常规数据处理,计算了地震烈度,并将计算的仪器烈度与现场地震宏观考察烈度进行了比较,有较好的一致性。  相似文献   

A note on the M w 6.3 earthquake in Iceland on 29 May 2008 at 15:45 UTC     

R. Sigbjörnsson  J. Th. Snæbjörnsson  S. M. Higgins  B. Halldórsson  S. Ólafsson 《Bulletin of Earthquake Engineering》2009,7(1):113-126

This preliminary study aims to investigate a M _w 6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber, style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures.  相似文献   

用于核工程地震安全性评价的中小地震水平向加速度反应谱衰减关系研究   总被引：1，自引：0，他引：1  

赵凤新  王海江  张郁山 《中国地震》2009,25(3)

利用美国西部的中小地震记录对基岩场地条件下的中小地震水平向地震动多阻尼加速度反应谱的衰减关系进行了初步研究,并分析了震级与距离对中小地震水平向地震动加速度反应谱衰减规律的影响.  相似文献   

2008年古田4．1、4．6级地震强震动观测记录   总被引：2，自引：0，他引：2  

张锦福  蔡辉腾 《华南地震》2009,29(3):111-116

水口水电站重力坝强震反应台阵在古田ML4．1、ML4．6地震中获得了强震资料,通过对观测资料初步分析,得到以下认识：如果仅用基岩自由场顺河向振动的峰值加速度进行估算．该大坝遭受的地震强度达到Ⅵ度。这与通过现场灾害评估得出大坝位于V度区外的结论相悖：坝底和基岩自由场竖直向和顺河向振动情况一致,但幅度存在差异;对于坝体的峰值加速度,相比较于坝底,坝中部三方向均有不同程度的放大,坝顶三方向均有不同程度的缩小：从坝底至坝顶。峰值加速度出现滞后现象,但并不明显,说明坝体刚性较大。此次地震中坝体主要呈整体振动特性。  相似文献   

Engineering source model for strong ground motion     

S.T.G. Raghu Kanth  R.N. Iyengar 《Soil Dynamics and Earthquake Engineering》2009

A new engineering source model consistent with seismological concepts for simulating strong-motion accelerograms (SMAs) is presented in this paper. The source region is modeled as a horizontally layered elastic medium to cater for site dependency. The moment field acting on the rupture plane is decomposed into space and time functions, which is a novel concept. The spatial and temporal components are determined for six well-recorded earthquakes using the corresponding recorded SMA. The obtained spatial variations indicate that they can be modeled as an anisotropic random field. The temporal components of all the six events are transients, with typical frequency spectra. Based on these results, a simplified source model is proposed for the synthesis of SMA during strong earthquakes. The model is validated by simulating strong-motion acceleration time histories at stations deliberately kept out of the modeling exercise. It is found that the present model is efficient in simulating observed time histories. The proposed model is also illustrated by simulating an ensemble of acceleration time histories for the Kutch earthquake of 26th January 2001 using only the few known source parameters.  相似文献   

Experimental evaluation of dynamic deformation characteristics of sheet pile retaining walls with fiber reinforced backfill     

R. Jamshidi  I. Towhata  H. Ghiassian  A.R. Tabarsa 《Soil Dynamics and Earthquake Engineering》2010

Fiber reinforced soil behaves as a composite material in which fibers of relatively high tensile strength are embedded in a matrix of soil. Shear stresses in the soil mobilize tensile resistance in the fibers, which in turn imparts greater strength to the soil. In this paper a study on the influence of synthetic fibrous materials in improving the dynamic response characteristics of fine sandy soil is reported. The project aims at converting fibrous carpet waste into a value-added product for soil reinforcement. A series of five shaking table tests using rigid box were carried out on Toyoura sand specimens reinforced with randomly distributed geotextile strips. The dynamic deformation characteristics of the reinforced sand are defined in terms of wall lateral deformation and rotation. The results clearly indicate the effectiveness of fiber reinforcement in improving dynamic properties of fine sand and deformation characteristics of fiber reinforced sheet pile retaining wall during shaking.  相似文献   

Planetary,solar and astrophysical relativistic electrons: Common energization mechanisms?     

Ilan Roth   《Planetary and Space Science》2007,55(15):2319-2323

Direct observations or deduced analysis indicate clearly that formation of intense fluxes of relativistic electrons is an important ingredient in the evolution of numerous active magnetized plasma systems. Examples of relativistic electron energization include the recovery phase of a planetary magnetic storm, post solar flare coronal activity and the afterglow of gamma ray bursts. It is suggested that there exists a universal mechanism, which may explain electron energization at the vastly different magnetized plasma environments. The favorite configuration consists of an inhomogeneous magnetic field anchored at a given magnetic structure and excitation of whistler waves due to external injection of low-energy non-isotropic electrons. The energization proceeds as a bootstrap process due to interaction with the propagating whistler waves along the inhomogeneous magnetic field.  相似文献   

Astrophysical ZeV acceleration in the relativistic jet from an accreting supermassive blackhole     

《Astroparticle Physics》2014

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The Cherenkov Telescope Array potential for the study of young supernova remnants     

《Astroparticle Physics》2015

Supernova remnants (SNRs) are among the most important targets for γ-ray observatories. Being prominent non-thermal sources, they are very likely responsible for the acceleration of the bulk of Galactic cosmic rays (CRs). To firmly establish the SNR paradigm for the origin of cosmic rays, it should be confirmed that protons are indeed accelerated in, and released from, SNRs with the appropriate flux and spectrum. This can be done by detailed theoretical models which account for microphysics of acceleration and various radiation processes of hadrons and leptons. The current generation of Cherenkov telescopes has insufficient sensitivity to constrain theoretical models. A new facility, the Cherenkov Telescope Array (CTA), will have superior capabilities and may finally resolve this long standing issue of high-energy astrophysics. We want to assess the capabilities of CTA to reveal the physics of various types of SNRs in the initial 2000 years of their evolution. During this time, the efficiency to accelerate cosmic rays is highest. We perform time-dependent simulations of the hydrodynamics, the magnetic fields, the cosmic-ray acceleration, and the non-thermal emission for type Ia, Ic and IIP SNRs. We calculate the CTA response to the γ-ray emission from these SNRs for various ages and distances, and we perform a realistic analysis of the simulated data. We derive distance limits for the detectability and resolvability of these SNR types at several ages. We test the ability of CTA to reconstruct their morphological and spectral parameters as a function of their distance. Finally, we estimate how well CTA data will constrain the theoretical models.  相似文献