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Transportation problems and needs in the aftermath of the 1985 Mexico City earthquake

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Title:
Transportation problems and needs in the aftermath of the 1985 Mexico City earthquake
Series Title:
Quick response research report ;
Physical Description:
50 p. : ill. ; 28 cm.
Language:
English
Creator:
Hobeika, Antoine G
Ardekani, Siamak Assaee
Martínez-Márquez, Alejandro
University of Colorado, Boulder -- Natural Hazards Research and Applications Information Center
University of Colorado, Boulder -- Institute of Behavioral Science
Publisher:
Natural Hazards Research and Applications Information Center
Place of Publication:
Boulder, Colo
Publication Date:

Subjects

Subjects / Keywords:
Emergency transportation -- Mexico -- Mexico City   ( lcsh )
City traffic -- Mexico -- Mexico City   ( lcsh )
Earthquakes -- Mexico -- Mexico City   ( lcsh )
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government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 50).
Additional Physical Form:
Also issued online as part of a joint project with the Louis de la Parte Florida Mental Health Institute (FMHI) Research Library's disaster mental health initiative.
Statement of Responsibility:
Antoine Hobeika, Siamak Ardekani, Alejandro Martínez-Márquez.
General Note:
Cover title.
General Note:
"Institute of Behavioral Science #6."

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Resource Identifier:
aleph - 001985200
oclc - 39041216
usfldc doi - F57-00028
usfldc handle - f57.28
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SFS0001109:00001


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NaturalHazards ResearchandApplicationsInformationCenterCampusBox482UniversityofColorado Boulder, Colorado 80309-0482TRANSPORTATIONPROBLEMSANDNEEDSINTHEAFTERMATHOFTHE1985MEXICOCITYEARTHQUAKEAntoineHobeikaSiamakArdekaniAlejandro Martinez-Marquez1987QuickResponseResearchReport#10This publication is partofthe Natural Hazards Research&Applications Information Center's ongoing Quick Response Research Report Series. http://ww.N.colorado.edu/hazards InstituteofBehavioralScience#6(303)492-6818

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TABLEOFCONTENTSACKNOWLEDGMENTS...ABSTRACT... ....I.INTRODUCTIONANDSCOPE...............II.ANEYE-WITNESSACCOUNTOFTHEEVENTSrrI.TRANSPORTATIONPROBLEMS.A.STREETANDHIGHWAYNETWORK-PROBLEMSFACEDB.TRAFFICCONTROLDEVICES-PROBLEMSFACED.C.MASSTRANSIT-PROBLEMSFACED...........D.EMERGENCYVEHICLES-PROBLEMSFACED...E.CROWDMANAGEMENTANDSHELTERS-PROBLEMSFACED.IV.TRANSPORTATIONACTIONSTAKEN.A.STREETANDHIGHWAYNETWORK-ACTIONSTAKEN........B.TRAFFICCONTROLDEVICES-ACTIONSTAKEN....C.MASSTRANSIT-ACTIONSTAKEN.....D.EMERGENCYVEHICLES-ACTIONSTAKENE.CROWDMANAGEMENTANDSHELTERS-ACTIONSTAKENV.FUTURENEEDS.REFERENCES.............Pageiiiii1513 13 161924293131374143454749

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ACKNOWLEDGMENTSThisworkhasbeenproduced through a grantfromthe EarthquakeHazardMitigationProgramofthe National Science Foundation.Inaddition,the authors wish to acknowledge the supportofthe Natural Hazards ResearchandApplications Information Centeratthe UniversityofColorado, Boulder in sponsoring ourtriptoSanSalvador following the earthquakeofOctober 10, 1986,fromwhichvaluable lessonsanddatahavebeenobtained.Wealsowishto thank anumberofstudentswhohaverenderedgreatassistancein ourfielddatacollectionefforts.Theseare Francisco Torres Verdin of the NationalAutonomousUniversityofMexico,LevMalakhoff of Virginia Tech,andLuis Garcia, Lucila Perez,EdmundoDelCastillo,RaulPerez, Jorge Lopez, Fernando Rodriguez,MarioMarquez,andPascualReyesof theAutonomousMetropolitan University.ThanksarealsodueanumberofMexicogovernmentofficialswhohaveparticipatedin our interviewsandhaveassistedusin the datacollectiontask.Theyinclude: GeneralRamirezGarrido-Abreu, General Coronado, Engineers Colin Arcos,BazanDeLaPena,ConradoRodriguez, Gustavo Escobar, LuisPommerencke,Gerardo Garcia Lara, Francisco Norena, GeneralBaravoMagana,Mr.Isaac Osorio Corpi,andLic.RebecaLopez.TheassistanceofDr.Victor Torres-Verdinhasalsobeenextremely valuable tousin the conductofour research inMexico.

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ABSTRACTAdescriptionof thestateofthetransportationnetworkandservices in the immediate aftermathoftheMexicoCity earthquakeisprovided.Thegoalhasbeentoidentifythe major problems faced in themanagementofthetransportationsystem pertaining to the overallemergencyresponseandrestorationofnormalcy.Thetype oftransportation-relateddecisions facedandthe consequent actions taken are documented.Thedocumentationisbasedoninterviews conducted with response agenciesofficialsinMexicoanda reviewofthepertinentliterature.Inaddition,officialdocumentshavebeenobtainedfromvariousMexicangovernment agencies,andare supplementedbyaneyewitness account of the unfolding of the events following theearthquake and therolesplayedbythetransportationsystem. Fivetransportation-relatedareashavebeenaddressed, namely: 1) thestreetandhighwaynetwork,2)trafficdevicesandcontrol,3)masstransit,4)emergencyvehicles,and5)crowdmanagementandshelters.Themajor problems faced in each areahavebeenidentifiedandthe subsequent actions taken are documented.Basedonthesefindings,the future needs inmanagementof thetransportationsystem in the aftermath of a major urbandisasterhavebeenoutlined.iii

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I.INTRODUCTION&SCOPEMexicoCityliesin a basin approximately 1,500 square kilometers surroundedbyhigh volcanoes.Itisthehomeof17millionpeople, with overtwomillionbuildings.At7:19 a.m.onSeptember 19, 1985,foralmost90seconds,thislargesthumansettlement in the worldwasshakenbya powerful earthquake (8.1onthe RichterScale).Infact,someresearchers (Ref.1)haveconcluded, basedoncollecteddata,thatonthe morningofSeptember 19,MexicoCity experienced notonebuttwoequally powerful earthquakes only27secondsapart.Consequently, the September1985earthquakesleftintheirwakeanemergency conditionrarelyparalleledinhumanexperience.Theextensivedestructioncausedbythe September earthquakesiswell documented. Table 1listsanestimateofthedamagesustainedbythecityas aresultofthe earthquakes.Notincluded in Table 1 are thenumberofliveslost;estimates vary widelyfrom4,596 to over 20,000 people. Table 2 summarizes the resourcesavailableanddeployed during theearlydays following thedisaster.Intermsofresponseandrescue, theeffortsandachi evementsofboth the governmentandvolunteer workersarehighlycommendable.Their achievements in rescue operationsandin.restoringorder arebetterap preciatedwhenonecompares the magnitudeofthedisaster(Table 1)tothe resourcesavailable(Table2).Although the emergencycrewofthe variouscityorganizationswerein the middleofashiftchangewhenthefirstearthquake occurredat7:19in themorning, both shiftsengagedtirelesslyin the rescueandemergencyoperations,oftenunawareofthe

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Table 1.Impactofthe Earthquakeonthe CityInfrastructure2InfrastructureBuildingsElectricPowerWaterDrainage SolidWasteLPGasTelephoneCBDRoadsSubwayDamageEstimate Reference957Destroyed 24,771Damaged38%Reduction in Distribution 2 capacityPowerFailure in 1/3ofthe City 227%CutbackinNormalSupply 3DamageNegligible 2 1.2xl0 6 m 3ofDebris 2 (Discarded over 2months)35%ofStorage Plants 2DamagedLocal-5%of Lines Disrupted 2DomesticLongDistance -70%ofLines Disrupted International -AllService Disrupted70%Reduction in Capacity 4NoSeriousDamage5SlightDamagetoLineNo.5OnlyTemporaryService Suspensions for Inspections

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Table2.ResourcesDeployedin theImmediateAftermath of the EarthquakeItemQuantity Reference Trained Volunteers35,000 2Untrained Volunteers15,000 2Fire Fighters8002Fire Vehicles1252Fire Stations76AmbulanceStations206RefugeeCamps1712Police Personnel15,3007PoliceAutoPatrols1,0907Motorcycles4507TowTrucks1057Police Jeeps1507PoliceVans317Police Helicopters107HeavyMachinery8503LightMachinery,500 33

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4fateoftheirownfamilies.Toaddtothe danger, the rescue operationshadtobecarriedout under a highlyrestrictivetransportationnetwork. Immediatelyafterthe earthquake, thetrafficcontrol systembecameinoperational;therefore,thestatusof the variousstreet links in thecitycenterwasunknown theemergencycrew.Asthe morning-rushtraffic,unawareofthe magnitudeofthedisaster,beganpouringintothecitycenter,the transportationlogisticsproblemsbecamemoreapparent. Consequently, themanagementandrestorationofthe transportationsystemwasrecognized asanintegralandvitalpartoftheemergencyoperations.Theobjectivesofthis report are to describethestateof thetransportationservices in the immediate aftermathofthe earthquakesandto discuss the roles playedbythetransportationsystem in the unfoldingofthe events following the earthquakes.Theoverall goalistoidentifythe major problems faced in themanagementofthetransportationsystem pertaining to the overallemergencyoperationsandeffortstorestorenormalcyandextractlessonsfromthisexperience.Thetype oftransportation-relateddecisions faced in the aftermath of the September earthquakesandthe consequentactionstaken are also documentedherein.Thedocumentationisbasedoninterviews conducted inMexico,a reviewofthepertinentliterature,andofficialdocumentsobtainedfromvariousMexicangovernment agencies,andissupplementedbyaneyewitness accountbyoneofthe authors,Dr.A.Martinez-Marquez. Fivetransportation-relatedareas are discussed,namely:1)thestreetandhighwaynetwork,2)trafficdevicesandcontrol,3)masstransit,4)emergencyvehicles,and5)crowdmanagementandshelters.

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5rl.ANEYE-WITNESSACCOUNTOFTHEEVENTSBasedoninterviews held with anumberofwitnesses,thisaccountisintendedtoshedlight on someofthemanyandyetvaried experiences recorded during the September19,1985MexicoCity Earthquake.Innarrativestyle,someofthecriticalsituationsexperiencedbymanyare described hereinbyanobserver involved inTrafficManagementatthe timeofthe earthquake.Asa witness,Dr.Martinez-Marquezreflectsonitemswhichwarrantfurtherconsideration in earthquake mitigation planning.IIItwasabout0718hoursofthatSeptember 19,1985daywhenIarrivedatthe parkinglotnear theoffice,toattendsomeusual things dealing with theMexicoCity computerizedTrafficControlSystemIwasin chargeof,whenI experienced a strange sensation asifthecarwasmovingandthefloorwassomehowshaking. Withinmyvisual scope the surrounding buildingsweresubjectedtoanoscillatorymotion barelyperceivable,whenIrealizedthatanearthquakewasin progress.Mydigitalwristwatchwasdisplaying0719hours. After experiencing such shakingofthe ground, I nearly ranintomyoffice.Twoyoungpeople, responsibleforthe operationoftheTrafficControl System,weretryingtostartthe computeron.Theyweredepictingsomepanic intheirfaces butweremore"worried about the computer not working properly. I didtrytohelp, butwejustcould notgetthe computer running. I enteredintomyoffice,grabbedmycamera,andwentouttoseewhatthesituationwasoutside.Itwasapproxi mately0735hours.

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FromPlazadeTlaxcoaque, near the Police Headquarters building, Istartedtowalkalong20deNoviembreAve.Northbound,-noticingamazementandsurpriseonmostpeople's faces, as well assomebuildingswhichhadatleastpartiallyfallendown.Thatfirstexperiencewasalso shaking,thoughemotionallynow.Inmypath, Iwasable to take a pictureofavisiblyleaning buildingfromtheintersectionof FrayS. TeresadeMierandSanAntonioAbadAvenue.Later on, the building, belonging to 'ConjuntoPinoSuarez,' completelyfelldowntoitsbasement.Somepeoplehadgotten the impressionthatthe causewasthe vibration generatedbya Policehelicopterwhichwasflying around.However,such a building,myunderstanding suggests,wasunder a collapsing processwhichcould notbestoppedbyanymeans.Thevibration generatedbythehelicopteracted as a very small perturbationonaratherunstablestructure.I decided towalkalong20deNoviembreAvenueand,attheintersectionwith JoseM.Izazaga, I turnedleftandcontinued taking photographs of mainly the general aspectsofthestreetsbut also ofstructuraldetailsandthevisiblyexcessive loadingwhichseveraldamagedbuildingswerecarrying, a loadingwhichappeared tobewellbeyondthe design load specifiedby'ReglamentodelasConstrucciones delD.F.I(TheMexicoCity Building-Code Standards).Anexampleofsuchloading consistedoffabricrollsoiledupinmorethansixrowsreaching a heightofat1east1.50 meters(5feet)abovethe steel platforms sustainingthem.Ingeneral themodeoffailureof these buildings resembledthatofa houseofcards. Therewerepeople leaving theI.laCatolicaMetrostationdisplay-6

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ing horror intheirfaces,mainly therewasnothingtodounder those unbelievable circumstances.AsIwaswalking alongJ.Ma.Izazaga Ave., hearing screamsofdespair,possiblyfrompeople trapped,myfeelingoffrustrationincreased mainly becauseonedoes notknowwhattodo.Suchfeelingsof despairandfrustrationtendtodisappearonefeelsrelievedwhenhearing the soundsofambulancesandPolicepatrolsarrivingatthesite.TheyaltogetherseemtoknowWHATandHOWtodounder those unthinkable conditions. Anumberofpeoplewereputtingwidebandstripesoffabricaround thedamagedbuildingsandsmall houses, as well as apartment buildings,inthearea.Suchfabrichadbeentakenfroma collapsed building hous ingclothmanufacturing companieswhichhadusedsomeofthefloorstostockpilerollsoffabricregardlessoftheamountofloading theywouldimposeonthestructure.Surrounding thedamagedbuildingsbystripesoffabricwas, perhaps, meanttoemphasize the excessive loadswhichhadcontributedtothe collapseofthe building. I continued along Eje CentraluntilIwasabletolookata collapsed buildingwhichhadmiraculously withstood the July 28,1957earthquake.Thebuildinghouseda very popularrestaurant(LaCopadeLeche)wheremanypeople usedtohavearatherearlybreakfast.Beinganoccasionalvisitortothatplace myself,wheremywifeandIhadfirstmet,myfeelingsweremixedbetweenwantingtohelp the people trappedinsideorsomehowbringingupthewholebuilding.Itwassomeconsolation,however, to seeonmyrightthe Latin-AmericanTowerstillin place.Sucha tower, a Mexico-U.S. Engineering design,hasbeenaleitmotifforstudyandadmirationtoCivil Engineering inMexico.7

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Comingfromthe AllendeMetroStation,Isawayoungmanin hisearlytwenties carryingbooksunder hisrightarmandsomedust covering his face, withnoexpressionatall.Iwaspromptedto askhimifheneededhelp but gotnoresponse.Thewholeexperiencehadbeensoshockingthatnoonecould ever expressitin words.Itwouldbeabsurd to expectanypersontobesoarticulateas to find inhis/hervocab ulary theneededwords. ThatyoungmanremindedmeofoneofmysonswhoshouldhavebeentravelingfromhometoworkbyMetroatthe timeofthe earthquake,andwhosewhereabouts I did notyetknow.Lookingwestward,attheintersectionofBenito JuarezandEje Central (Lazaro CardenasAve.)onecould not help but notice thecollapsed 'Hotel Regis'onBenito JuarezAve.andthemanypeoplewhoweremerely watching in helplessness. Northwards, I noticedseveralmoredamagedandcollapsed buildings. I decided to returntotheofficebywayofMaderoStreet.GlimpsesofthethingsIsawbackin 1957,whi1e in theMi1itary Service,begantoemergeinmymindastrafficconditionswereworseningonthestreets.Therewasno power, andthetrafficsignalswerenot functioning. Driverswerepassing otherdriverstogetaheadbypress ingtheircars'horns.Fewpeoplewereawarethata major earthquakehadoccurred since theywereused to frequent butlightearthtremors.Meanwhile,continuous honkingwasin progressandnotrafficpolicewereathand.Theywerepossibly preparing tobesent outfromtheirownrespective Sectors (or Coordinating Areas)orperhapstravelingtotheirrespective posts. I continued walking along20deNoviembreSt.backtomyoffice,encountering peopleofallwalks oflifewalking in despair.8

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9Inthe meantime, thearrivalofpolicepatrolsandambulanceshadbegun.Tostateitbluntly,allthoseunitsparticularlyofthe policeweredoing everything withintheirpowertohelp people understand thegravityofthe overall problem.AsIwaswalking back, apolicehe1icopterwasflyingaround the areawhenaheavynoisewasheardfroma buildingatthe 'Pino Suarez'Metrostationfollowedbya rushofpeopleawayfromthestation.Thebuildingwasmadeofboxedsteelcolumnsandtrussedbeamssupporting reinforced concreteslabs.Fortunately,whenthe collapse occurred, theMetrostationwasnot functioning; otherwise, the victimstollwouldhaverisen.Possibly thevibrationinducedbythe flyinghelicopteracceleratedtheinevitablecollapseofthe unstablestructurealready dangerously leaning southwards.Thesteel-framedstructurewasbentlikealargecantileverbeambeforeitsactualcollapse.Byabout 10:00o'clock,Istartedatripwestbound along Fray ServandoT.deMier,thistimebycar,tomorecloselyexaminethe prevailingtrafficsituation.Itwasverydifficulttomoveduetopeople standing by,justobserving thedamagedbuildings.Thetrafficsignalswereoutofordersothatpolicemenhadtoregulatetrafficcirculationattheintersections.Nearthe crossingof5deFebrero with Fray ServandoT.deMier, several buildingshadtotallycollapsed.Inparticulara building withflatslabstructureshowedonly thecolumnsstanding, whereas the roofshadstackedupontopofoneanother.Onthe northwest cornerofthatintersection,onebuildinghadcollapsedatthe topfloors.Thenearbyonehadcollapsedonthefrontwhile thebackofitwasstillstanding,showingtheinsideofeachfloor.

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Between Lazaro Cardenas and CuauhtemocAve.,travelingwasnearlyimpossibleduetothemanycollapsedbuildings,includingaportionofthe'Televisa'Complex(atelevisionstation),and asteeltrussedtowerwhich hadfallenoverDr. Rio delaLozaAve.(continuationofFray S. T. de MierAve.,westwards).Very fewcarswereallowedtoenterthissectionoftheroadway.AttheintersectionwithCuauhtemoc Ave.thebuildingonthesoutheastcorner,housingseveralradiobroadcastingstations('RadioFormula')hadalsocollapsedatthetopfloors.Along ChapultepecAve. asecondaryschoolbui 1dinghadcollapsed,killinga numberofteenagers.Thenearbyapartmentbuilding,failingatthetop,hadcompletelytiltedaround,showingthetopoftheroofasa'facade'lookingsouthward.1IWetriedtoentertheColoniaJuarezArea(towardthenorthfromChapultepecAve.) wheretrafficencountereda numberofIcul-de-sacsIcreatedby a few damagedbuildingsand the'non-existenceofdetoursigns.Thissituationledintoanatypicalgridlock,affectingthesurroundingroadwaysofReforma Ave. andInsurgentesAve.WedecidedtoleavethatareaandtravelalongInsurgentesAve. Southbound,sincea numberofcollapsedbuildingshad beenreportedalongthesectionbetweenChapultepecAve. and Alvaro ObregonAve.throughthePoliceRadiochannels.Such asectionwasimmediatelycordonedoffbythepoliceforceandthetransitandothertrafficweredetouredaroundthiszone whichextendeda fewblocksaheadtothesouth.InreturningtotheofficealongAlvaroObregonAve.,westoppedthecarnearCuauhtemoc Ave. and walkednorthfora fewblocksnoting10

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11the roofsofthe building housing theSecretariadeIndustriayComercio (MinistryofIndustryandCommerce),hadcoll apsed. Within our visiontherewereanumberofotherbuildingspartiallydestroyed.NeartheintersectionofCuauhtemocandChapultepecAves.manypeoplewerewalking in the nearbystreetwhichwasclosedtoalltraffic.ThiswasduetothefactthattheMetrolinerunning alongCuauhtemocSt.wasoutofservice.Backin theoffice,the following assessmentofthe generalsituationwasmade:a) the ComputerizedTrafficControl CentralComputerexperienceddamageatthe disk driveunitslevel,though theCPUwasfunctioning properly;b)communicationbetweenthe supervisory computerandthe equipmentonthestreetwascompletelylost,sothatitwasnot possible toidentifythecurrentstatusofneitherthe localcontrollersnor the subarea computers; c) therestofthetrafficsignals,mainly the electromechanical type, experienced minordamagethough several signal postshadcollapsedorwerecovered with constructiondebris;d)theTrafficRoadwayNetworkwasseverelydamagedinitscapacitysincemanyisolatedlinkscould notbeusedbyvehicles.Thereweremanyotherstreetswhichwerealsoclosedbytheinitiativeofthe neighborhoodresidentswholaterclaimedthatsomebuildingsweresodamagedthatthey mightfalldownatanymoment;e)bymeansofthe PoliceRadioSystem, anumberofreportshadbeengatheredonthedamagedorcollapsedbuildings,andaninventory

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12of placeswherevictims rescue operationswereneeded.However,wedesperate1yfelttheneedforaroadwayinventory, including:i)thenumberof lanes availableafterdiscounting thoseneededforactivitiessuchasheavymachinery demolitionactivityor victims rescue operations;ii)thestreetsclosedwhichcouldbeopenedtotrafficwithin24hours or so;andiii)findingalternativeroutes to avoidtrafficcirculationaround severelydamagedareas.

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13III.TRANSPORTATIONPROBLEMSA.STREETANDHIGHWAYNETWORK-PROBLEMSFACEDUponthe occurrenceofthe September 19,1985earthquake approxi mately70%of thenormalcapacityoftheMexicoCitycentraltransportationnetworkwaslost(Ref.4).Thelossofthestreetcapacity in thecentralregionwasnotduetostructuraldamagesto thestreetsalone.Infact,thelatterwastheleastof the contributing elements.Thenetwork capacitywasmainly reduceddueto blockages causedbystructurescollapsingintothestreetsandcompoundedbydebrisfromcollapsedstructuresstored in thestreetsas search, rescue,demo1ition,andclean-up progressed.Alsocontributing to thelossin capacitywerethe cordons used to minimize thethreatfromnear-collapsestructuresandtofacilitaterescue operationsandheavymachinery assembly.Inaddition,atleastonesource (Ref.8)identifiedthe gathering ofcrowd(volunteers,relativesofvictims,andon-lookers) as another element in the closureandcapacity reduction ofstreets.Finally,anumberof massive grid10cks in the hours following the 7:19 earthquakehadeffectivelyshutdownmanystreetlinks.Mostof these problemswereconcentrated in thecentralregion ofMexicoCityshownin Figure1.Thisisazonewhoseprimarystreetsare under the controlandmonitor of theMexicoCity computerizedtrafficcontrol system since 1982. Figures 2 alsoshowsthedistributionof the capacity reductionsonastreet-by-streetbasis within theaffectednetworkshown.Theextentof disturbances within the areashownincludes:

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Figure 1. 14w I ..13!ThemaP of severly damagedregionS in theaftermath ofthe1985 Mexico Citearthquakes.

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FigUre2. ROADSCLOSEDlocationofstreetsclosed tothrough trafficin the aftermathofthe September1985MexicoCityearthquake.15

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i)Access-Controlled Freewaysii)Two-WayAvenuesiii)Ejes Viales* 10.7kms.19.akms.68.9kms.16B.TRAFFICDEVICESANDCONTROL-PROBLEMSFACEDTheMexicoCity computerizedtrafficcontrolcenterhasbeenin operation sinceNovember1982.Inthiscenter,thestatusofeach signalisdisplayedona boardmap.Whenthe signalindicationforthemainstreetisgreen, a greenlightisdisplayedonthe board.Whenthemainstreethas a redindication,the greenlightonthe boardisoff.Theredlightonthe boardisonlylitwhena signal hasfailed.Theamberlightsonthe boardshowthelocationofinductive loopdetectorsin thecitynetwork.Inthe aftermathofthe September earthquake,thisentire systemwasrenderedinoperational.Although theCPUofthecentralcomputerwasfunctional,the disk driveunitsweredamaged.Worseyet,the communicationbetweenthecentralcomputerandthestreethardwarewasalsolost,henceanyrapid assessmentofthe operationalstatusoflocalormastercontrollerswaspracticallyimpossible.Themaincauseofthe communicationlosswasthefailureofthe ducts housingthesigna1cables.These concrete ductshadshearedatthejointsas aresultofthe earthquake.ItisbelievedthatPVCductsmayhavebeenmoreappropriate since they are considerablylesssusceptibletoshearforces.Thefailureofthepowerductsalsocaused the Ejes Viales areone-waystreetswith 5ormorelanes withonepossibletransitcounter-flow lane.

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17malfunctioningofstreethardware suchassignalcontrollersand loopdetectors.For example,ofapproximately634 loopdetectorsinthecitynetwork,onlytenwereoperational.Asecondaryboardatthetrafficcontrolcenterassessesthedegreeofcongestiononvariouscriticalintersectionapproachesbymeasuringtheloopoccupancytime.Asteadyyellowlightontheboardindicatesanintermediatelevelofcongestion.Thisboardwasalsonotoperationalduetotheloopmalfunctionsmentionedearlier.Meanwhile,manytrafficsignalswerenotfunctionalduetowidespreadpowerfailures.Not knowingtheextentofthedisaster,majorlock-upsbegantoformattheintersectionsasthepeak-hourtrafficbegantoenterthecitycenterasusual.Thetrafficconditionswerefurtheraggravatedbyvehiclesenteringthenormallythrough-linkswhich had becomecul-de-sacsduetocollapsedstructures,debris,etc.Consequently,fewhoursafterthefirstearthquake,majorgrid-locksformedinthecitycenter,seriouslyinterferingwiththesearchandrescueoperations.Theformationofsuchgrid-locksidentifiesthreeotherproblemsfaced,namely, 1)theeffectivedisseminationofinformationtothepublic,2)thelackofquicklyimplementablediversionanddetourplans,and 3)the1ackofenforcement.Withproperdi sseminationofinformationintheinitialhoursaftertheearthquake,manyvehiculartripsdestinedforthecitycentercouldhaveeitherbeencancelledoraborted.Suchaneffectiveinformationdisseminationabilityis,ofcourse,conditioneduponanequallyeffectiveandquickmeansofsurveyingtheconditionsinthearea.Itispossiblethattheextentof

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18damageswereinitiallyperceived toberelativelylightandconsequently suchaninformationcampaignwasnotdeemednecessary. Nonetheless, in the days following the earthquake the information providedbyradioondetourswasnotspecificenoughtoidentifyclosedstreetsandalternateroutes.Thepublicwassimply advised to avoidcertaingeneralareas.Anobstacle in implementing a quicktrafficdiversionanddetourstrategywasthe lackofavailabilityofasufficientnumberoftrafficsigns of the kind neededtocarryoutanoperationofsuch magnitude. Consequently,driverswouldvery often find themselves instreetswhosecirculationdirectionhadbeenreversedorwhichledintoa"cul-de-sac"condition.Inaddition,specialtrafficsignswereneededtowarnvehicularandpedestriantrafficofsomeof theextra-ordinaryconditionswhichprevailed, such as the near-collapsestructuresor demolitionandrescueworkin progress .... Finally,the enforcement ofsuchagreatnumberofdiversions,detours,andcordonswasalso problematic. Thiswasparticularlythe case in theinitialhoursafterthefirstearthquakewhenmanyofthe needed cordonsanddetoursweresetupbyvolunteersandneighborhoodresidentsthemselves,wholackedanofficialenforcementauthority.Inthe dayswhichfollowed, the primary goalwastorestoretrafficservices tonormalas quicly as possible.Assuch,effortsweremadeto reduce thenumberandsizeofcordon areasandto devi se network-widediversionstrategiestofacilitateandgraduallyimproveonaccessibility.Thedecisionwasreachedaftermanyinterorganizationaldebatesbetweenthetrafficdivisionof the Policeandthetransportationdivision(CGT)of theofficeofMayor.Inconnection withthisgoal,pri-

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19oritieswereneeded to beestablishedforthe clean-upandopening of closedstreets.Thelackofa systematicstreetclean-upstrategywasalsoa problem confronted intrafficmanagement.C.MASSTRANSIT-PROBLEMSFACEDThemasstransitsystem inMexicoCityiscomposedof four majormodes:buses,trolleybuses, tramsandthe Metro. Together, thesemodesoftransportationprovide over56%of thetotaldailytravelbyallmodesinMexicoCity, asshownin Table 3. Table 3.TheBreakdownof Daily Person-TripsbyModesWithin theMexicoCity Metropolitan Region.ModeDaily Person-Trips Percent SurfaceTransit10,085,554 33.3 (bus,trolley,tram)Metro6,916,628 22.9Walk*6,480,244 21.4Car4,530,414 15.0Jitney1 ,951,851 6.4Taxi164,327 0.5 OtherMeans143,928 0.5 Total 30,272,933 Thiswouldamountto approximately17millionperson-tripsa day.Inaddition,twopara-transitmodes,namelyjitneysandtaxis,supply6.4%and0.5%,respectivelyof thetotaldailytrips.Asexpected, thestreetsin thecitycenter are heavilyutilizedastransitandpara-transitroutes. Figures3aand3bshowthe concentra-tionofbusandtrolleyroutes within thecitycenter.Inaddition,allmetrolinesalso convergeatthecitycenter(Fig.3c).Consequently, Trips longer than 5 minutesorapproximately400meters.

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Bus Routes HIH-H Figure 3.BusrouteS in the MexicoCity studynetwork.20

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'i1"O11 eyLines\I I "II 21figure 3b.Trolleylinesin theMexico CitystudY network.

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Metro Lines 1I I "II 22 Flgure3 c .Metrolines tnrougntneMe
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23the earthquakedamagesto thecentralcitystreetnetwork caused majordisruptionsin the surfacetransitoperations.Themetro 1ines,carryinganestimated 297,000 passengersatthe timeofthe earthquake,wereonly momentarily shutdownforinspection.However,the surfacetransitmodeshadtoundergo routeandschedul e changesduetostreetclosuresdescribedearlier.Suchchanges requiredaneffectivedisseminationoftherelevantinformationtothe public.Theroute changesanddetoursalsohadtoconsider important changes intravelneedsandpatternsproducedbythe earthquakeitself.Thesechanges included thetravelneedstoshelters,reliefcenters,first-aidstations,andtripsmadetoincidentnodesandinformationcentersin searchofmissingrelatives.Inlightofthese additionaltrippurposes, problems arose regard ingsettingupmake-shiftstationsandacquiring additional buses toaccommodatethe increasedridershipdemand.Additional buseswerealso indemandtotransportexcess passengers along those segmentsofmetrolineswhichweretemporarily outofservice.However,sincesometransitbuseswereusedtotransportvictimsandreliefsupplies the supplyofbuseswassmaller than usual.Inshort,itwassoonacknowledgedthattherestorationofmasstransitservicestoanacceptable levelwasanessentialstep in expeditingthereturntonormalcy in the aftermathofthe earthquake inMexicoCity.Tothisend, majortransitproblems faced included: oRouteandschedule changes o Service to specialtripgenerators o Disseminationoftransit-relatedinformation

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o Inspection ofMetrolineso Alternative service to shut-downMetrolineso Short supply of busesduetoalternateusesD.EMERGENCYVEHICLES-PROBLEMSFACEDTwomajor problems existed in theemergencyresponse operations.First,therewereaninsufficientnumberofemergencyunits.Second, theemergencyvehicleshadtobedispatched under highly uncertain conditions.Inaddition, therewereproblems experienceddueto disrup tions incommunicationsystemsandlack of coordinationamongemergencyresponse agencies.Theemergencyresponse resourcesandfacilitiesinMexicoCity are extremely limitedcomparedtoothercitiesof comparablesize.Forex ample, while there are76firestationsand8,000 firemen inLondon,MexicoCity has only 7firestationsand800firefighters,whooperate125fireenginesandworkintwo12-hourshifts.The125fireenginesaccompaniedbyonly20ambulances. Figure 4showsthe location of thefirestationsandambulances inMexicoCity.Itmustbenotedthatthe location of the ambulances are not fixed butratheraredistributedac cording todemandvariationswith the time ofdayanddayofweek.Theyare usually stationed near small police modules. Despitesuchlimited resources, following the1985earthquake, theMexicoCityfirebrigadewasforced toengageinactivitiesas diverse asremovingcrushed walls, quenchingfires,preventing gas leakages,andsupplying water to medicalfacilities.Within thefirst24-hour period afterthe earthquake, thefire brigaderesponded to193cases offireand236cases of gas leakage (Ref. 2).Inthe threedaysafterthe earthquake,351casesoffirewerereported; Figure 5showsthe loca-24

PAGE 30

25=o o lD I\mbulances FireStations/Figure4.Locationoffirestationsandambulances inMexicoCity.

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LegentLocationof-FireOutbreake GreenBeltAreaofConcentrated Da::tages SpreadFireo(Hate126Figure 5. Locationoffireoutbreaks in thethreedaysfollowing the September 19,1985MexicoCity earthquake(Ref.2).

PAGE 32

tionofthe majorfireoutbreaks. A second problemwasin dispatching emergencyvehiclesunder unknownroute conditions.Emergencyunitssuch as ambulances, rescue teams,andfirevehicleshadtomakenumerousattemptsanddiversions,usuallybytrialanderror,in ordertoaccess areaswheresecondaryandlocalstreetswereclosed. Thiswasparticularlythe case within the "Co1onia Juarez"and"Co1oniaRoma"zones. Figure 6exemp1ifiesthe vehicledi spatchprob1emthroughshowingthespatialdistributionofthecriticalfacilitieswhichwerepotentialoriginsordestinationsofemergencyvehicles.Thedispatchofemergencyunitswasfurthercomplicatedduetodisruptions in communicationlines.Forexample, thelogisticsdivisionof the policehadlosttheirtelephone connection totheirradio dispatchcenter(Ref.9).Furthermore, the Metropolitan policehadlosttheirentiresystemofcommunication with the exceptionofhandradios (Ref.8).However,through the four channelsavailableonthesehandradios,theywereable tocommunicatewith ambulancesandfiredivisions.Finally,therewasa general lackofcoordinationamongthe various response agencies.Forexample, theArmy,thepolice,andmayor'sofficelaunched independent condition surveys to assess theaccessibilityofthestreets,only to discovertheirredundancy in the meetingswhichfollowed. Furthermore, in thefirst72hoursafterthe earthquake, the ambulancesandfireengines took whatever routeswereavailablebytrialanderror,independentofeachother.Inaddition,theywerenot pro-27

PAGE 33

q1I0:ll'ital.. Cl iotc.LEtnergenc Y Service 28 Poltl'.1calOffice f treioo 0 OJ, a Danger-proneZoneSh..e)(:gas 7 u IICigure 6. Locationof critical buildindS in the MexicoCity studyarea.

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29vided, nor soughtinput,regarding thestreetconditionsfromthe agencieswhichhadconducted condition surveys.Itshouldbeemphasizedthat,in time, the problemsstemmingfromthe lackofcoordinationwereidentifiedandactionsweretakentorectifythem, as discussed in the chapterwhichfollows.E.CROWDMANAGEMENTANDSHELTERS-PROBLEMSFACEDAccordingtoGeneralV.Coronado,HeadoftheMexicanMetropolitanPolice,therewerefourdifferentcrowdtypes assembled in thevicinityofincidentpoints,each type posing unique problemsandrequiring special responses.Thefour types were: victims, victimsrelatives,on-lookers,andvolunteers.i)Victims Victimswhodid notneedimmediate medicalattentionneededtobetransported toshelters.However,theirevacuation toshelterswasnot alwaysaneasy task since such victimswereconcerned aboutlootersandremainedtoguardtheirpossessions.Inaddition,dueto a1950rent-freezeordinance, theresidentialrentshadbeenfrozenatthelowratesineffectatthe time. Conse quently,manyvictimswerereluctanttoevacuatetheirheavilydamagedplacesofresidenceforfearof losingtheirlow-rentprivilegeoncetheirbuildingswerereno vated.

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ii)Victims' Relatives Relativesoftrapped victimswouldalso gather near the incident points.Thecontrolofthe emotionally-chargedrelativeswasespeciallydifficult,andusuallybeyondthe policecapability(Ref.8).iii)On-LookersThecrowdofon-lookerswouldoftenbeabsorbedintothe volunteer forceorwouldotherwisebedispersed. Thiswasparticularlythe caseafterthe seconddaywhenvolunteerswereregisteredandgivenidentificationtags.Itwastherefore easy todistinguishon-lookersfromvolunteersandrequiretheirdispersion. iv) Volunteers Volunteers played avitalrolein searchandrescue operations.Approximately 50,000 volunteers adayparticipatedin the rescueactivities.Allgovernmentofficialsinterviewedhadconsensusonthe importanceofactions takenbyvolunteer individualsandgroups.Theonly majorproblemwith the volunteerswasthe unequalspatialdistributionofsuch forces.Themainconflictwasincontrollingthe excess volunteercrowdatcertainincident points.30

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31IV.TRANSPORTATIONACTIONSTAKENA.STREETANDHIGHWAYNETWORK-ACTIONSTAKENActions taken regardinq theroadwaynetwork in the severelydamagedcitycenterincluded thoseaimedatrapidlysurveying the conditionsofthe variousstreetlinks,settingupcordons,anddisseminating informationtothe public. Other actionsrelatedtotrafficcontrol,publictransit,andemergency vehicles willbediscussed in separatesections.i)Survey of ConditionsUnderthe auspicesofthe Secretary GeneralofPoliceandTraffic,the IIDisasterWorkHeadquartersllwassetuptogather data regarding thestatusof the networkstreetlinksandtomonitortheirconditions with time.Themainobjectivewasto rapidly evaluate the degreeofutilityofeachlinkonthe networkfortrafficcirculation.TheinitialinventorystartedonThursday, September19atabout1300hoursandwascompletedbyFriday, September20atnoon.Thedatawereprimarilycollectedthrough patrol vehiclesandten policehelicopters,allin radio communication with thelogisticsheadquarters (Ref.9).Helicopterswerevery useful in surveying theaccessibilityofthearea;however,itwasdifficulttoassess the conditionsofsecondarystreetsfromabove.Theincoming infonnationwasthen emptied onto acitymapbythetrafficteam.Oncethemapwascompleted,itwasestimatedthattheroadwaynetwork capacity within thedamagedzonewasreduced to nearly30%ofthenormalcapacity. Unfortunately, theinitiativewasnot takentoquickly publicize theeffortsin progressandtofurnishsuchamapanddata basetootheragencies involved in emergency response operations.

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Assuch, organizationssuchas the OfficeoftheMayororthePub-.licWorksDepartment engaged intheirownindependent condition surveys.TheTransportation Divisionofthe Mayor's Office (D.D.F.),forexample, dispatched twenty observers,onfoot,tocollectdata regarding thenetworkconditions (Ref. 10).Eachobserverwasassigned a pre-desig nated path towalkandsurvey.Thedatawasthen returned to theofficeandemptied onto amap.Theinformationwasupdated in asimilarfash iononadailybasis.Mr.Pommerencke,the engineer in chargeofthisoperation, highlyrecommendedthismethodofinformation gathering.32ii)CordonedAreas Certa in areaswerecordoned primarilytofacilitatethe disasterreliefactivities.Other reasonsforcordoningoffareas included public protectionfromnear-collapsestructures,restorationofutilityservices,andpreventionoflooting. Atotalof54cordonsweresetUPwithin thedisasterzone, thelargestbeing about10blocksby10blocks.TheArmy,Police,andthe NationalGuardwerethemainorganizations in chargeofenforcingandestabl ishing cordoned areas.Inaddition,someareaswereinitiallycordonedbyvolunteersfirsttoarriveincertaindisastersites.Table 4summarizesthe locationofthese54cordoned areas along with theauthorityin chargeandthe reason behind theaction.

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Table 4. Cordoned-OffAreasin theImmediateAftermath of the September1985Earthquakes (Ref.11)33Cordon1.LuisMaya&Juarez2.Dr.MoraSt. 3. Balderas&Hidalgo 4. Hidalgo&Veracruz5.Valerio Trujano&Hidalgo6.CentralLazaroCardenas&Hidalgo7.Lazaro Cardenas&Cuba8.PedroMoreno&RivaPalacio9.HeroesSt.,Mina&Vio1eto10.Lerdo&Magnolia11.VictoriabetweenLazaroCardenas&Lopez12.Moctezuma&Guerrero13.Zaragoza&Alvarado Bridge14.Bucareli Ave.,AbrahanGonzales&Lucerna15.Turin, Versa11es,Chapu1teoecAve.&Berlin16.NapolesSt.,Chaou1tepecAve.,Dinamarca&Londres17.PaseodeLaReforma&Insurgentes, Berlin&Hamburgo18.Juarez&Lopez19.Juarez&Reforma20.CuauhtemacAve.,Dr.Norma,Dr.Pauster&CentralAve.21.Dr.Norma,Dr.Pauster&Cauchemco22.SanAntonioAbad#231&5deFebrero,RoaBarcenas&RafaelDelgado23.Netzahua1coyot1,20deNoviembre&5deFebrero24.Flamenco,20deNoviembre&PinoSuarez25.Izazago,20deNoviembre&5deFebrero26.Regina,20deNoviembre&PinoSuarez27.Mesones,PinoSuarez&CorreaMayorAuthorityArmy ArmyArmyNoneArmyNoneArmyNone NoneNonePoliceandNat'lGuardNonePolice Police20Volunteers PolicePo1 ice Nat'lGuard&VolunteersArmyNat'lGuardNat'lGuardNat'lGuardNat'lGuardNat'lGuardPo1 ice Nat'lGuardPoliceReasonCo11apsedB1dgsCall apsedB1dgsCollapsedBldgsCo11apsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCo11apsedB1dgsCollapsedBldgsCollapsed SldgsDamagedNeighborhoodsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsRescueOperationsRescueOperations CollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgsCollapsedB1dgs

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40.Tamau1ipas,NuevoLeon&CadereitaNat11Guard41.AlvaroObregon&NuevoLeonConstructionCrewTable 4 Continued28.IsabelLaCato1ica, Venustiano Carranza&20deNoviembreNat11Guard29.FrayServando, Bolivar&Eje Centra 1 Nat'lGuard&Police30.Dr.Liceaga,LazaroCardenas&Dr.Barragan Police31.Augustin Delgado,Xocongo&Police&LorenzoBoturini Volunteers32.FrayServando,SanAntonio Police&Abad&Chima1popocaVolunteers33. Chima1poooca, FrayServando&C1avijero10Vo1 unteers34.SanCosme,SerapioRendon,AntonioCaso,Migua1Schultz, Alfonso Herrera,NeighborhoodEdison&Insurgentes Residents 35.PaseodeLaReforma,RioTamesistoRioMarineNone36.Chapu1tepec,Oaxaca&GlorietadeInsurgentesNone37.Puebla,Oaxaca,Monterrey&Chapu1teoecNone38.Oaxaca,Tabasco&ColimaNone39.Oaxaca#54Nat'lGuard42.43.44.45.46.47.48.49.50.Monterrey&OaxacaUpto ChapultepecDr.Balmis,Dr.Lucio&CuauhtemocDr.Pasteur,Dr.Lucio&CuauhtemocDr.Andrade,Dr.Marquez&Dr.ArcoCalleSol#66,Lerdo,Galeana&CameliaCalleCdo.deCamelia#5&LerdoChapultepec#385,Medellin&Monterrey Xola,Castilla,Andalucia&&CorrespondenciaSanAntonioAbad,RoaBarcenas&JuanaA.MateosPoliceNeighborhoodResidents PoliceNoneNeighborhoodResidentsNeighborhoodResidentsNoneNat'lGuardNat'lGuard34Coll apsedB1dgsZonalDamagesZonalDamagesToSurveyDamagesToSurveyDamagesToSurveyDamagesToprotectresidents involved inemergencyoperations 35.Near-Co11apseBldgsNear-Co11apseBldgsNear-CollapseBldgsNear-Co11apseBldgsNear-CollapseBldgsNear-Co11apseBldgsNear-Co11apseBldgsZonalDamagesNear-CollapseBldgsCollapsed General HospitalComplexTruckTrafficComplexCarrying DebrisNear-Co11apseBldgsNear-Co11apseBldgsNear-CollpaseBldgsCollapsedBldgsCollapsedBldgs

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Table 4 Continued5l.Dr.Barragan, Universidad, PolicePartialCollapseCasasGrandes&Morenaof theRadioSta. 52.Dr.Vertiz#800,Mitla&Fed.HgwyPartial Collapse Universidad PatroloftheCommunica-tionsBldg53. Xola, Universidad,LazaroPolice Partial CollapseCardenas&CumbresdeoftheCommunica-Acultzingo tionsBldg54.Mosqueta,Lerdo&GaleanaNoneCollapsedBldgs35

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iii)InformationDisseminationTheinter-organizationaldisseminationofinformationoccurredinthedailycoordinationmeetings.Duringthedaysfollowingthequake,acoordinationmeetingwasheldeverymorning (7to8:30a.m.)atthePoliceandTrafficHeadquarters.RepresentativesofvariousorganizationssuchastheArmy,PublicWorks, andOfficeoftheMayorwerepresent.Inthesemeetingsinformationregardingthestatusofthestreetnetworkwasexchanged. Mainly,theinformationgatheredbythePoliceandthemilitarywould be exchanged andanalyzed,henceprovidinganadditionalresource-allocationdecisiontooltoparticipatingorganizations.Interestingly,inthesemeetingsthetraditionalconflictsandrivalriesamongvariousgroupsweresetasideandallgroupsappearedtohave adeeplyconcernedspiritofcooperationinthefaceofthedisaster.TheArmyalsosolicitedinformationfromthePoliceCommandPostandtheTransportationDivisionoftheCityHa11(CoordinacionGeneral delTransporte.CGT.de DepartamentoDistritoFederal)onanas-neededbasis.TheCityMayorandthePublicWorksDepartmentalsoacquiredinformationfromtheOfficeofPoliceandTrafficaswellastheTransportationDivision(CGT).Thedisseminationofinformationtothepublicwasmainlythroughthenewspapers and governmentradioandtelevision;airtimeincommercialradioandtelevisionwasnoteasilyavailable.Policepatrolswerealsofurnishedwiththelatestinformationonthestatusofthenetwork and wouldprovidethosetothepublicuponrequest.36

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BoththeTrafficOfficeofthePoliceandtheTransportationDivision(CGT)publishedinthenewspapers,maps showingthenetworkconditions.The mainobjectiveonthefirstdaywastodiscouragethepublicfromtravelingtotheseverelydamagedzones.TelevisionappearancesweremadebypoliceandCGTrepresentatives.OnFriday,September20,forexamo1e, Dr. Martinez-MarquezastherepresentativeofPoliceandTraffic,advisedthepublicina20-minutetelevisioninterview,torefrainfromtravelingtothedamaged zonesun1essabsolutelynecessary.OnSunday, September22,arepresentativeofPoliceandTrafficwasinterviewedbya commercialtelevisiontoinformthepublicofthestatusoftheroadwaysystem.Similarappearanceswere made bytheMr.Dominguez-PommerenckerepresentingtheCGT.ThepublicwasinformedthatbyMonday, September23,travelactivitiescouldresume.Thatsamenight,ageneralreportwasalsopresented,describingtheprevailingconditionsa10nqthemaintravelcorridorsaffectedbytheearthquakes.Meanwhile,thepublicwasagainurgedtoavoidtheheavilydamagedzonessothattherescueoperationscouldcontinue.They werealsourgedonbehalfoftheSecretaryGeneralofPoliceandTraffictousetheirprivatevehiclesonlywhenabsolutelynecessary."Therearestillmanypeoplefightingforsurvivalundertherubb1es,"theSecretaryGeneralexclaimed,"Theysurelydeserveachance."B.TRAFFICDEVICESANDCONTROL-ACTIONSTAKENMajortrafficproblemsencounteredintheinmediateaftermathoftheearthquakeincluded:1.Formationofwide-spreadgrid-locksdueto:37

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38oLackofrapid information dissemination oAbsenceofquick diversionstrategiesoInitiallackofenforcement 2.Lossofpowertotrafficsignals3. Failure ofcommunicationlinesofthe central signal system4.Needforspecial warninganddiversion signs 5.Absenceofa systematic clean-upstrategyDueto theenormousmagnitude of these problemsandlimited resources,mostactions takentoalleviatethemhavebeenratherlimited in scope. Regarding the disseminationofroadwayinfonnation to the public, ac tionsweretaken not immediatelyafterbut in thedayswhichfollowed the earthquake.Theconsequencewasthe formationofextensivegridlocks in the central area in theinitialhours following the earthquakewhichhamperedthe rescue operations.Manyofthe grid-lockswereremovedby"flushing out" the vehicles trapoed in cul-de-sacs using policeescorts.Theoperations were,however,timeconsumingandresourceintensive,andthusfurtherjustifiedtheneedfora rapid information disseminationcampaignaimedatpreventingsuchproblems.Theinformation dissemination in thedayswhichfollowedwasmostly through preparing drawingsofthe re-designedtrafficnetworkwhichwerepublished in the newspapersandshownonthecommercialandgovernmenttelevisionchannels.Thesedrawingswerebasedoninventories of thedamagedareas performedbythe Police, the PublicWorks,andthe OfficeoftheMayor(CGT).Thepolice used thei rhe1i coptersandthe ground patrol reports tomakeafirst-handassessmentofthe conditions.ThePublicWorksSecretariatalsomadea quickandreliableassessmentofthestreetconditions through theArmy'ssupport in theformof

PAGE 44

motorcyclistssentoutonreconnaissance missions.Suchinventoryactivitiesemphasizeddamagedbuildingsandtheireffectsonthestreetlinks.Thetransportationdivision(CGT)ofthe OfficeofMayoralsoperformedtheirownsurveyofthe conditions in the days following the earthquakebydispatching on-foot personnel to thefield.Themainobjectiveofthe newspaperandtelevi sion informationbulletinsissuedbyCGTwasto discourageanytraveltoorthrough thedamagedareas.Theinitialinventoriesassembledatthe PoliceandTrafficSecretariatshowedthatthe overallroadwaycapacity in the centralzonewasreduced to30%;buttherewasapossibilityofimmediate re-openingofseveralstreetssoastoincrease theavailablecapacityto50%.Suchcapacityretrievalforced anumberofunexpectedobstaclesincluding the simultaneousactivitieswhichlacked coordinationandtheinterestofsomegovernment agencies tokeeocertainstreetscordonedoff.Thenetworkre-design,however,wascarriedoutbythe PoliceandTrafficSecretariatwith theobjectiveofkeeping the cordonstoaminimumandproviding diversions around the blockedareas.Aspecificoutcomeofsuch a re-design processwastheidentification,onasection-by-sectionbasis,ofa capacitydeficitformobilityfromnorth to south near the "Zocalo" area. Consequently,itbecamenecessary to reverse thetrafficcirculationonsomenorth-southstreets.Evensomeavenues with medianshadtobeconverted toone-waystreetstomakeupforthe capacitydeficitin thesoutherlydirection.39

PAGE 45

40Regarding enforcement, the police forcewasnotatalladequate to controltrafficandenforce thesetupcordonsanddiversions.Assuch, theArmyandvolunteersgreatlyassistedthe Police,particularlyin the enforcement of cordoned areas.Mostof the Policeeffortsweredirectedatmanagingthetrafficatintersectionswithfailedsignals.Inthe hoursafterthedisaster,trafficcontrolatintersectionswasrestored toanacceptable level of service through a wide-spread presence of the police force. A balanced assignment ofprioritiesbythe Policeatintersectionswithfailedsignalizationhelped preventfurthergridlocksandexpedite rescueactivities.Themassive police involvement intrafficcontrolwasmaintained for thefirsttwodaysuntilsignal operationsatcriticalintersectionswererestoredanddiversionstrategiesweredevisedandimplemented.ByFriday, September 20th, afirstdraftoftrafficdiversion planswerepreparedbytheTrafficDivisionandsubmitted to the Police Operations Divisionforitsimplementation.Theagreedupondiversion plansincluded the following features: a)Minimizethenumberof lane closures alongvitalstreetlinks.b)Identifyroadwaylinkswhichcouldbeopenedbysimplyremovingsmallamountof debrisandartificialobstacles placedbyneighborhood residents to close thoselinks.c) Identify those sections of avenuesthatcouldbeusedfortwo-waycirculationonanalternatingone-waybasis.d)Identify thosestreetsonwhichthetrafficdirectioncouldbereversed withminimalperturbationsandeffortin order tofurtherfacilitatethe rescueanddemolition operations. e) Identify sectionswhichcouldbeusedin the reversiblemodeto favor a dominating directionatdifferentper iods of the day.

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41f) Prepare drawingsofthe re-designedtrafficnetwork for disseminationtothe public through newspapersandtelevisionstations.g)Assess theneedfortrafficsigning alongmaintravel corridors affectedbydiversion plans.Theimplementationofthese plansonSaturday, September21required designandmanufacturingofanumberof special signs (Fig. 7).Thesesigns included: a)Woodenbarricades withmountedref1ectorized meta1ic sheetsandsupportedby1.S-inchsteelangle sections.b)Atwo-waysignfororiginallyone-waystreets,framedin a redcircleonanavyblue background.Thesignshowedtwoarrows, a white arrowforthe originia1directionofthestreetandanopposing red arrowtowarndriversofthe existenceofon-comingtraffic.c) A sign toprohibitdriversfromentering aroadwaysec tionwheredemolitionactivitieswerein progress.d)A sign towarnpedestriansofdemolitionactivities.Themassive demolitionandclean-upactivitiesalso brought about theneedtoestablishlocations outside themostaffected regionwherethestructuraldebris couldbedeposited. Pathsweredesignatedandsignedtobetakenbytrucks transporting the debris to the depositsites.Themainobjectivewasto speedupthe clean-up processsothatthe debriswasnot piledupin thestreets,thushamperingthe vehicular mobility.C.MASSTRANSIT-ACTIONSTAKENModifying atransitroutewasnot merely aproblemoffinding de tours around thedisasterzones but also aproblemofproperly informing the users.GiventhatinMexicoCity,transitservices are supPliedbythe CityGovernment(RUTA100), the Transportation Coordination division(CGT)of theMayorsOfficewasable to takedirectactionsto:a)BackuptheMetrobyallocatingmorebuses totransport

PAGE 47

42.' ,. ..,:. .,# :",. ..," CD Chevron to Indicate Detour ,\.L\ ooo iSiyil for collapsed buildings or demolished combined withdo-not-entersignMAVYBLUE,-__ .L.RE--_-/-...a WHITEOne-wayStreetconverted intotwo-way @) Sign for' pedestrianstowalk around the zoneaffectedbya damaged Figure7.Special signs used inMexicoCityafterthe September1985earthquake (Ref"4).

PAGE 48

43passengers along those segmentsofanyMetrolinewhichwastemporarily outofservice.b)Allocate buses to provide limitedassistancetovictims in carryingtheirmoreappreciated belongings. c)Modifythe surface routes accordingtoadailyassessmentoffurtherroadwayopeningsafterdebris removal.d)Usethe newspapers tokeepthe public informedofanymajor changes inroutes,busstations,andservicefrequencies.Inspiteofthe reduced mobilityofpeople in thefirstthree days, the earthquake brought about majortravelpatternchanges.Shelters,medicalcenters,reliefandsupplycenters,andinformation centershadbecomemajor special "Trip Generators."Duetothesizeof theMexicoCity regionandthevolumeoftransitpassengers handled,itwasnot possible togreatlymodify thetransitroutes or implement special routes as a response to thesetravelpatternchanges. Consequently,mostsuchtransitridershadto findtheirwayaround thetransitnetworktotheirdestinationsbytrialanderror.D.EMDRGENCYVEHICLES-ACTIONSTAKENInthe aftermathofthe earthquake,itwasnecessary tomobilizescarce medical resources to widelyscatteredlocation in thecity.Sporadicfireshadalso broken out inmanylocations (Fig.5).Emergencyresponse agencies, generally understaffedandunderequipped,hadtomakethemostefficientuse or theirresources.Anessentialelement inefficientuse of resourceswasthe time savingswhichcouldberealizedthroughselectionof the best dispatch routes.Thestreetnetwork conditions, however, changed very rapidly. Therewasnoestabl ishedmechanismtokeeptrackofthese changes. Therefore, the incident pointsweresimply reachedbytaking routesthat

PAGE 49

44wereusually takenandmodifyingthemas theneedarose.Thevarious informationbulletinsonthestreetconditions assembledbythe reportsfromthegroundPolicepatrolsandthe ten Police helicopters providedsomeinsightinto the majorstreetlinkstobeavoided.Butsuchinformationwasnot continually updated nor systematicallyavailable.Thenewlyformedorganization,SIPROR(SistemadeProteccion Civil y Rescate) could takeupthevitalfunction ofroadwaycondition information inventoryanditsdissemination toallemergencyresponse agencies.SIPRORwasconceived in1984as a division of the PoliceandTrafficSecretariat.Itsfunctionwasto coordinateemergencyresponse operations in the faceofmajordisasters.Butatthe timeofthe1985earthquake,SIPRORwasorganizationally notyetpreoared toassumesucharole.Inaddition,as anewgroupitwasnot well recognizedbyothergovernmentagencies. Thus,atthe timeofthe earthquake, theroleofSIPRORwassimply tokeepaninventoryofsuppliessuchas theamountofwater availableforthefiredepartment, thenumberof vehicles in use, the locationofambulances,etc.Since the earthquake,however,a major emphasishasbeenplacedondevelopingSIPRORas the focal point in coordinating theemergencyresponse todisasters.Itsfunctions could include a computerized inven tory of resourcesandsuppliesavailable,themostupdated surveyofstreetconditions, the location of incidentsandthe type ofemergencyservicesneededateachlocation,receivinganddisseminating informa tionfromandto the various organizationsengagedinemergencyresponse, set-upofsheltersandre1iefposts,andmanagementof reliefsuppl;esandother resources sentfromothercountries,to mention afew.

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45E.CROWDMANAGEMENTANDSHELTERS-ACTIONSTAKENInitiallyafterthe earthquake, the protectionofneighborhoodsfromlootingwasprimarily handledbyresidentsthemselves.Theyusuallylivedin nearbytentsandguardedtheirresidences.Onthe second day, the PoliceandArmybecameactivelyinvolved in guarding thedamagedareasandpreventing lootingandriots.Atthistime a volunteer registrationschemewasdevised.Badgesweredistributedtoregisteredvolunteers primarily in ordertotakeeffectiveaction in dispersing the on-lookers. Immediatelyafterthedisaster,171shelterswereset up bythe Cityandstaffedbyvolunteers.Therefugeesweretransported to thesesheltersbybuses as well as in volunteeredvehicles.Free gasolinewasprovided to the volunteervehicles,whichalsohadtoberegistered.TheMinistry ofCommerceandIndustrydistributedbasic foodstuffssuchas corn, milk, bread,flour,beans,rice,andcookingoilto theshelters.Water, however,wasin short supply.Evenfourweeksaftertheearthquake, water tankswerestillproviding only 1literof water per person perdayascomparedto the average pre-earthquake water consumption of50literspercapitaper day.Longqueueswereformedforwater.Thewater shortages created a charged atmospherewhichattimes 1edtoriots.Containing the tense conditions.wouldhavebeenmuchmoredifficulthaditnotbeenforawidedistributionof water tankersandwaterplasticbags throughout thecity.Thewater supplieswerecontin uously refurbishedbythe water suppliesarrivingfromtheU.S.Information dissemination about the victimsandtheirwhereaboutswashandled mainlybyradioandtelevisionstations.Boththecommercialandgovernment-ownedtelevisionchannelswereused extensively in

PAGE 51

46exchanging messagesbetweenvictimsandtheirrelativesandfriends.ThetelevisionChannel11, belonging to the National PolytechnicInstituteofMexico,provided a continuous broadcast faci 1itatingmessageexchanging. Othermassmediawerealsoactivelyinvolved."RadioUniversidad," a radiostationbelonging to the NationalAutonomousUniversity, broadcastinformationontheroadwaytrafficconditions,particularlyalongmostheavily traveledcorridors.Thenewspapers published alistofvictims rescuedandthe place they couldbereached.

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47v.FUTURENEEDSIn'regard to the surveyofstreetconditions inMexicoCity, theneedexistedforacentraldata baseaccessibletoallagencies involved in emergency response.Manytimes,similarsurveyswereconductedandduplicatedbytwoormoreorganizations under conditionswhichdemandedthe bestutilizationof timeandotherresources.Inaddition,the accumulated data neededtobeincorporated onto acitymaowhichwasquickly reproducedandmodified as conditions changed.Criticaldeci sions also needed tobemadeoncordoningareas,divertingtraffic,clean-upofstreets,andmanagementoftransitresources.Suchcapabilitieswould, of course,bemorefeasiblewith a main-frame computerfacility.Since main-framefacilitieswerenotavailablefor72hours following the September19earthquake, abatteryoperated micro-computeristhereforerecommended.Themicrocomputerfacilitywouldhavegraphical networkeditingcapabilitiesandbestationedata centralcorrmandpost.Allinformation regarding the conditionsofthestreetnetworkswouldbecommunicatedto thecommandcenter.Thecomputerizedmapofthe network could thenbemodified basedonincomingdata.Thelatestgraohical documentationofthe network conditionscanthenbemadeavailabletoallinterestedpartiesin thefonnofa hard-copymaporbytelecommunicationlinks.Figure 8showsa schematic diagramofthe proposedcommandcenter.A micro-computer graphical networkeditingsoftwarehasbeendevelopedforMexicoCityandiscurrentlybeingtestedandmodified.Inadditionto networkeditingcapabilities,sucha software could alsohavefeatureswhichcouldmakeituseful as atrafficmanagementtool in de-

PAGE 53

48Figure 8. A schematic diagramofthe proposedtransportationemergencymanagementheadquarters.

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49cisionssuch asestablishing cordon areasandsimulatingalternativetrafficdiversionstrategiesaround these areas as well as assessing theneedforquantitiesandtypesofspecialtrafficcontrol devices.Thesoftwarecanalsobeused in dispatching emergencyvehicles.Ashortestpath algorithm couldbedeveloped toidentifytheshortestpathfromanyorigintoanydestinationin a network basedonthelatestnetwork conditions. Furthermore, atransitmodulecouldbedeveloped tobeused as a decision tool inmanagingthetransitresources,particularlytransitvehicles,inlightof thediversityofdemandsforsuch resources. Aprioritizationschemeforstreetclean-up could alsobedevelopedbydevelopingpriorityindicesforeach closedstreetlinkwhichare a func tion of reasons behind thelinkclosure,therelativeimportance of thelinkin accessingcriticalresponsefacilities,andthe degreeofutilityofthelinkin servingtrafficandsurfacetransitroutes.Thecommandcentermayalso furnish informationonthestreetconditions to the public through ahot-linetelephonenumber.Inshort,such acommandcenter couldeffectivelyfulfillanumberofneedsidentifiedregarding thetransportationnetwork.Namely,itwouldi.promotemoreefficientuseofresouresii.providewideaccess to informationonnetwork conditions toallinterestedpartiesiii.promotefurtherinter-organizationalcooperation;andiv.provide a real-time microcomputer-basedtransportationdecisiontool.

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50REFERENCES1.S. -1(. SinghandG.Suarez,IIOverviewof Seismology of theRegion,1IPresentedattheASCEInternational Conferenceonthe1985MexicoEarthquakes, September 19-21, 1986,MexicoCity.2.TokyoMetropo1itanGovernment,IIReportonthe Investigation of the Earthquake inMexico,1IDisasterMeasuresPlanning Section,Bureauof GeneralAffairs,TokyoMetropolitanGovernment,June1986.3. Castaneda Narvaez,IIE1FuncionarioPub1icoAntelos Danos CausadosporLosSismos,1IPresentedatSimposioNaciona1DeIngenieria Sismica, SorredadMexicanaDeIngenieria Sismica,November6-7,1986,Ixtapa, Zihuatanejo,GRO,Mexico.4.A.Martinez-Marquez, IITrafficManagementDuringthe AftermathofAnEarthquake inMexicoCity," Submittedtothe 65thAnnualMeetingofthe Transportation Research Board, Washington, D.C., January1986.5.F.Noreiia,IIResponseto theEmergencyCausedbythe1985MexicoEarthquake,1I PresentedattheASCEInternational Conferenceonthe1985MexicoEarthquakes, September 19-21,1986,MexicoCity. 6. ProvidedbyReneBazandeLa Pena,Chief ofEmergencyVehicle Services(CuerpodeBomberos)ofMexicoCity.7.ProvidedbyRebecaLopez,Associate Director of Logistics Division of SecretariaGeneraldeProteccion y Via1idad (PoliceandTraffic)ofMexicoCity. 8. Interview withEngineerDavidColin Arcos,Sub-Directorof Super vision,MexicanMetropolitan Police,September10,1986.9.Interview withRebecaLopez,the Associate-Director of Logistics Division of theMexicoCity PoliceandTraffic Office (Secretaria GeneraldeProteccion y Via1idad).10.Interview with EngineerLuisDominguezPommerencke,Advisor to theMayor,TheMexicoCity Office ofMayor(DepartamentoDistritoFedera1).11.Secretaria GeneraldeProteccion y Via1idad,IIRelacionDeZonasAcordonadas,1ISubdireccionDeIndicadores,September1985.12. Interview with GeneralBravoMagana,theformalHeadofSIPRORandwith EngineerConradoRodriguez Hernandez,TheActing Director ofSIPROR.


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