哈工大地震工程工程地震部分第四章強(qiáng)地震動(dòng)的觀測和數(shù)據(jù)處理課件

EngineeringSeismology(2)GroundMotionInstrumentationandDataProcessing地震動(dòng)的觀測(observationofGM)可以提供定量的數(shù)據(jù)可以測量地震破壞作用的全過程，能夠分別研究并測量導(dǎo)致建筑物破壞的各種因素不但為地震烈度和工程抗震措施提供定量數(shù)據(jù)和理論依據(jù)，同時(shí)又檢驗(yàn)從抗震研究實(shí)踐中總結(jié)出來的認(rèn)識、理論和辦法是否符合實(shí)際，從而加深人們對于抗震客觀規(guī)律的認(rèn)識，成為不斷推動(dòng)地震工程研究發(fā)展的重要手段。

如果沒有強(qiáng)震觀測及其所取得的科學(xué)資料，就談不上現(xiàn)代地震工程學(xué)的發(fā)展。地震工程之所以能成為一間定量的科學(xué)是和強(qiáng)震觀測的成果分不開的。

根據(jù)測量得到的地震加速度記錄，計(jì)算了大量的反應(yīng)譜曲線，獲得了“平均反應(yīng)譜”或“標(biāo)準(zhǔn)反應(yīng)譜”，使反應(yīng)譜分析得以真正應(yīng)用于工程設(shè)計(jì)。地震動(dòng)特征的統(tǒng)計(jì)分析和結(jié)構(gòu)抗震理論的發(fā)展。例如，從震源參數(shù)、傳播介質(zhì)的性質(zhì)演算地震動(dòng)，隨機(jī)合成地震動(dòng)時(shí)程，從彈性反應(yīng)譜到非彈性反應(yīng)譜，烈度定量標(biāo)準(zhǔn)及其觀測儀器的建立，以及場地條件對地震動(dòng)的影響，地震時(shí)地基與結(jié)構(gòu)的相互作用等研究，都是在取得了強(qiáng)震觀測記錄的基礎(chǔ)上發(fā)展起來的。

ThefoundingfatherofthestrongmotioninstrumentationprogramintheUnitedStatesisJohnR.Freeman.AftertheTokyo,Japanearthquakeof1923,andtheSantaBarbara,CaliforniaandMontreal,Quebecearthquakesof1925,hestimulatedimportantearlyinteractionsbetweenU.S.andJapaneseinstitutionsonearthquakeengineeringandwrotethefirstsignificantbookintheEnglishlanguageonearthquakeengineering,EarthquakeDamageandEarthquakeInsurance(Freeman,1932).Heparticularlyrecognizedtheurgentneedforaninstrumenttorecordthestrongshakingduringearthquakes,andtheresultofhislobbyingeffortswasthattheCoastandGeodeticSurveywasauthorizedtodevelopandinstallsuchinstrumentsin1932.Ninemonthsafterthefirstinstrumentswereinstalled,thefirstsignificantstrongmotionrecordswereobtainedfromtheMarch10,1933LongBeach,Californiaearthquake.強(qiáng)震儀的原理絕對靜止參考系擺（pendulum）的原理強(qiáng)震儀主要由五個(gè)系統(tǒng)構(gòu)成拾振系統(tǒng)，直接測量地震動(dòng)的裝置，通常稱為拾振器或擺。根據(jù)其所記錄的物理量不同可進(jìn)一步分為位移計(jì)(擺)、速度計(jì)(擺)和加速度計(jì)(擺)。通常一點(diǎn)要采用一個(gè)測量豎向運(yùn)動(dòng)的拾振器、二個(gè)測量相互垂直的水平向運(yùn)動(dòng)的拾振器。

記錄系統(tǒng)，機(jī)械、光、電流計(jì)、模擬磁帶、數(shù)字磁帶和固態(tài)存儲(chǔ)；觸發(fā)-起動(dòng)控制系統(tǒng)，節(jié)省存儲(chǔ)空間等；預(yù)存儲(chǔ)系統(tǒng)，避免“丟頭”、節(jié)省存儲(chǔ)空間；時(shí)標(biāo)系統(tǒng)，以便各分量、相鄰各點(diǎn)地震動(dòng)的比較、分析，相對時(shí)標(biāo)系統(tǒng)（晶振）或絕對時(shí)標(biāo)系統(tǒng)（GPS時(shí)間信號）；電源系統(tǒng)，一旦強(qiáng)震發(fā)生造成正常供電系統(tǒng)的破壞和失靈，要保證整套儀器驅(qū)動(dòng)運(yùn)轉(zhuǎn)、線路控制、以及時(shí)標(biāo)和光源正常工作。Timingsystemswerenotusedinmanyoftheearlyanalogaccelerographs,buttheybecamemoreimportantastheanalysisbecamemoresophisticated.High-precisiontime,usuallyfromsatellitesystems,isnowessentialwiththedigitalaccelerographsthatproviderecordsofaftershocksandothersmalleventsinlargenumbers.Precisiontimetogetherwithpre-eventmemoryallowdigitalaccelerographstoimproveearthquakelocationsbeyondwhatispossibleusingonlythetraditionalhigh-gainseismicnetworks.Instrumentation臺網(wǎng)的合理布局：應(yīng)設(shè)置強(qiáng)度高、頻度大的地震區(qū)；根據(jù)歷史和現(xiàn)今的地震活動(dòng)性和地質(zhì)構(gòu)造情況臺陣的設(shè)計(jì)儀器的正確設(shè)置：確保儀器的可靠性和精度要求臺網(wǎng)維護(hù)管理技術(shù)措施,確保儀器參數(shù)精度、儀器正常運(yùn)行等。

GoldenStateBankbuildingonVenturaBlvd.inShermanOaks.Thisisa13-storyreinforced-concretestructureinstrumentedbytheCaliforniaStrongMotionInstrumentationProgram.Itsresponsewasrecordedinthe1971SanFernandoearthquakeaswellasthe1994Northridgeearthquake.Inthenorth-southdirection,thelateral-force-resistingsystemconsistsofshearwallsateitherendofthebuilding,whileintheeast-westdirection,amomentframeresistslateralforce.Crackingcanbeobservedinthewestern-mostshearwall.Arraylayout臺陣設(shè)計(jì)，根據(jù)具體的觀測內(nèi)容，給出能提供完整資料的儀器布設(shè)方案,包括確定臺陣的類型和規(guī)模，給出儀器的最優(yōu)布設(shè)方案，臺陣的設(shè)置方法，提出對儀器性能、儀器安設(shè)和維護(hù)管理技術(shù)的具體要求等。地震動(dòng)觀測臺陣，震源機(jī)制臺陣、傳播效應(yīng)(衰減）臺陣、局部場地效應(yīng)臺陣以及特殊地震動(dòng)臺陣等。結(jié)構(gòu)反應(yīng)臺陣，房屋結(jié)構(gòu)(工業(yè)與民用)地震反應(yīng)臺陣、地基-結(jié)構(gòu)系統(tǒng)地震反應(yīng)臺陣、橋梁、水壩、高爐、水塔、煙囪、核反應(yīng)堆等結(jié)構(gòu)地震反應(yīng)臺陣等，了解各類典型結(jié)構(gòu)在強(qiáng)烈地震作用下的反應(yīng)特征和破壞規(guī)律，確定結(jié)構(gòu)在地震作用下的反應(yīng)和導(dǎo)致破壞的數(shù)學(xué)物理模式。

許多國家和地區(qū)強(qiáng)震觀測臺網(wǎng)規(guī)模迅速擴(kuò)大（1）美國全國5000臺以上USGS臺網(wǎng)約1000臺，加州4000臺以上TriNet，實(shí)時(shí)監(jiān)測臺80臺，撥號臺100臺（2）日本全國5000臺以上，臺站間距25km

K-net有線遙測強(qiáng)震臺網(wǎng)1000臺1999年臺灣地震后，增設(shè)2000臺的新計(jì)劃（3）臺灣1500臺以上（數(shù)字強(qiáng)震儀）集集大地震獲取記錄1萬條以上（4）伊朗1000臺以上；墨西哥430臺（1995）其它有強(qiáng)地震觀測的國家（地區(qū)）阿根廷、加拿大、智利、印度、意大利、希臘、新西蘭、尼加拉瓜、秘魯、波多黎各、（前）蘇、委內(nèi)瑞拉、（前）南等

In2000,therewerebetween10,000-20,000strongmotioninstrumentsoperatingworldwide.Mostseismicallyactivecountrieshaveatleastafewaccelerographsinoperation.Industrialnationswithhighseismichazardshaveextensiveprograms.Countrieswiththemostextensivestrong-motionnetworksareJapanandTaiwan.TheUnitedStateshasnetworksoperatedbytheUSGeologicalSurveyandotherorganizations.NetworksinothercountriesthathaveproduceddatafrommajorearthquakesinrecentyearsareinMexicoandTurkey.Ambraseys(1997)estimatedthatthereare2000strongmotioninstrumentsoperatinginEurope,andthatthesehaveproducedover2500recordings.Unfortunately,itisstillpossibleforlargeearthquakestooccurinpopulatedregionsoftheworldbutnotberecordedbyanylocalstrongmotioninstruments(e.g.Gujarat,India,January26,2001,Mw=7.6).我國的強(qiáng)震觀測一級強(qiáng)震監(jiān)控區(qū)（8個(gè)）二級強(qiáng)震監(jiān)控區(qū)（13個(gè)）太陽能電池~220VGPS天線三分量加速度計(jì)固態(tài)強(qiáng)震記錄儀調(diào)制解調(diào)器電話線避雷器強(qiáng)震遙測中心地震動(dòng)便攜計(jì)算機(jī)UPS電源電源避雷器數(shù)字強(qiáng)震臺站框圖Withsomanydifferentorganizationsoperatingstrongmotionaccelerographnetworks,asingleglobalsystemofaccesstostrongmotiondatahasneverbeencompletelyachieved.Varioussystemsfordatarecoveryhavebeenputinplace.Perhapsthemostthoroughforthelate1900.swastheWorldDataCenter,whichsoughttocompileandreproducevarioustapesorcomputerdisks.Seekinsetal.(1992)preparedaCD-ROMwithmuchofthedatagatheredinNorthAmericathrough1986.OtherCD-ROMdatasetshavebeenpreparedbyAlcantaraetal(1997),Cousins(1998),Ambraseysetal(2000),Lee(2001),andCelebietal(2001).DistributionovertheInternetalsobeganinthelate1990’s.In2000,manystrongmotionprogramsoperatedactivewebsitesfordatadistribution.AparticularlyusefulU.S.programfordistributionofstrongmotiondatawastheoneestablishedbySCECforsouthernCaliforniadata,andexpandedwithsupportfromCOSMOStootherdatasets.ThedatabasecouldbeaccessedthroughtheWorldWideWeboperatedbytheSouthernCaliforniaEarthquakeCenter(http://smdb.crustal)ortheConsortiumofOrganizationsforStrongMotionObservationSystems().DatafromlargeandsmallearthquakesrecordedontheextensiveKyoshinNetandKiban-KyoshinNetinJapancouldbeaccessedthroughtheirexcellentwebsites(.k-net.bosai.go.jp/and.kik.bosai.go.jp/,respectively).ThecontentoftheEuropeandataisalsoavailableonline(.isesd.cv.ic.ac.uk/esd/frameset.htm,Ambraseysetal,2001)數(shù)字化零線（baseline）調(diào)整，零線校正，Butterworth數(shù)字濾波器作雙向?yàn)V波，截止頻率可通過事前噪聲記錄與地震記錄的傅立葉譜分析確定。對位移時(shí)程用最小二乘法調(diào)整零線以消除線性趨勢。

Significantaccelerogramsrecordedonfilmformatsareeventuallydigitizedanddistributed.Agreatdealofefforthasbeendevotedtothisprocessbecauseoftheimportanceofaccurateinformationforearthquakeresistantdesign.Althoughtheinstrumentsrecordacceleration,estimatesofthegroundvelocityanddisplacementarealsoimportantforbothengineeringandgeophysicalresearch.Thusnumericalintegrationoftherecordsisimportant.Thechallengeindoingthisaccuratelyisdeterminingexactlywherethetruezerolevelofaccelerationislocatedontheaccelerograms,bothonthefilmrecordandondi