简介:Inthisarticle,weanalyzethecharactersofSV-componentreceiverfunctionofteleseismicbodywavesanditsadvantagesinmappingtheS-wavevelocitystructureofcrustindetail.Similartoradialreceiverfunction,SV-componentreceiverfunctioncanbeobtainedbydirectlydeconvolvingtheP-componentfromtheSV-componentofteleseismicrecordings.OuranalysesindicatethatthechangeofamplitudeofSV-componentreceiverfunctionagainstthechangeofepicentraldistanceislessthanthatofradialreceiverfunction.Moreover,thewaveformofSV-componentreceiverfunctionissimplerthantheradialreceiverfunctionandgivesprominencetothePSconvertedphasesthatarethemostsensitivetotheshearwavevelocitystructureintheinversion.ThesynthetictestsshowthattheconvergenceofSV-componentreceiverfunctioninversionisfasterthanthatoftheradialreceiverfunctioninversion.Asanexample,weinvestigatetheS-wavevelocitystructurebeneathHIAstationbyusingtheSV-componentreceiverfunctioninversionmethod.
简介:针对10种不同坡角的凸起地形,采用基于透射边界的有限元-有限差分计算方法,研究了局部凸起在SV波斜入射时,地震动峰值加速度放大倍数和反应谱谱比随入射角度的变化规律。结果表明:(1)地震波以一定的角度斜入射时,地表大部分观测点的峰值加速度放大倍数大于垂直入射的情况;(2)在计算模型宽高比一定的情况下,最不利入射角度与坡角有一定关系,且地表最不利位置随坡角增大由凸起台地边缘向中心移动;(3)入射角度对凸起地形地震反应谱特性的影响十分显著,不但影响谱比的幅值,也影响谱比曲线的形状,斜入射时各关键节点大部分周期点的谱比值大于垂直入射,入射角度对反应谱中的高频成分影响较为显著,而对长周期成分影响不大。
简介:Toevaluatetheimportanceofthecanyontopographyeffectsonlargestructures,basedonarigidframebridgeacrossa137-m-deepand600-m-widecanyon,theseismicresponseofthecanyonsiteisanalyzedusingatwo-dimensionalfiniteelementmodelunderdifferentseismicSVwaveswiththeassumptionsofverticalincidenceandobliqueincidencetoobtainthegroundmotions,whichareusedastheexcitationinputonthepierfoundationsofthebridgewithimprovedlargemassmethod.Theresultsindicatethatcanyontopographyhassignificantinfluencesonthegroundmotionsintermsofincidentangle.Thepeakgroundaccelerationvaluesvarygreatlyfromthebottomofthecanyontotheuppercorners.UnderverticalincidentSVwaves,attheuppercornersofcanyonthepeakgroundaccelerationsgreatlyincrease;whereasthepeakgroundaccelerationsdiminishatthebottomcornersofcanyon.UnderobliqueincidentSVwaves,theshakingofthecanyonslopeperpendiculartotheincidencedirectionismuchmoreseverethanthatoftheoppositesideofcanyon.Andthegroundsurfacehasbeencharacterizedbylargerdeformationsinthecaseofobliqueincidentwaves.Itisalsoconcludedthatthelowpiersandframeofthecontinuousrigidframebridgearemoresensitivetothemulti-supportseismicexcitationsthantheflexiblehighpiers.Thecanyontopographyaswellastheobliqueincidenceofthewavesbringsthecontinuousrigidframebridgesevereresponses,whichshouldbetakenintoaccountinbridgedesign.
简介:一、地震基本参数表1 地震基本参数表发震时间年月日时分秒震 中 位 置微 观宏 观东经北纬东经北纬参考地名震级(ML)震源深度(Km)震中烈度 地震类型 198810310612119°29′25°39′1194°257°福清县城西南409Ⅴ孤立型 微观震中与宏观震中基本吻合,如图1所示,仅有4公里左右的偏离。二、地震烈度分布图12-1为根据现场调查所勾划出的地震等震线图。划分出Ⅴ、Ⅳ、Ⅲ三个烈度区。图12-1 1988年10月31日福建福清地震等震线图Ⅴ度区:为极震区。Ⅴ度等震线经过福清的龙溪,宏路,油圹,安民,柏渡等地,呈长轴北北东向的椭圆形,长轴长约17公里,短轴12公里,面积150平
简介:一、地震基本参数表1 地震基本参数表发震时间年月日时分秒震 中 位 置微 观宏 观东经北纬东经北纬参考地名震级(MS)震源深度(Km)震中烈度 地震类型 199705311451117°11′25°35′117°11′25°34′永安西南526Ⅵ前主余震型 宏观震中与微观震中基本吻合,稍偏南1分。二、地震烈度分布本次地震震中位于永安市小陶镇张家山一带,震中烈度Ⅵ度强。Ⅵ度区:为极震区。Ⅵ度等震线北起永安市小陶镇大陶村,东至漳平市的赤水镇,南经龙岩市新罗区万安镇的安前村,西到连城县曲溪镇的古白石村,呈长轴北东走向的准椭圆形。长轴长38公里,短轴宽24公里,面积约700平方公里(见图23-1)。