ERCAdvanceGrantTrans-Atlan3cImagingof

Lithosphere-AsthenosphereboundaryaStory

Sa#shSinghIPGParis

NTUSingapore

TransAtlan3cILAB:Summary

•  ERCAdvanceGrant•  SubmiFedin2012•  Awardedin2013,3.5m€•  StartedinNovember2014•  LedtoasecondERCStartGrant,in2015•  Fivemarineexperiments•  ImagetheoceanicLithosphere-AsthenosphereBoundary(LAB)

•  AlsofundingfromUKNERC,GermanDFG,USNSFandSchlumberger

CVmaFers:Sa3shSingh-1•  GrewupinIndia•  PhDattheUniversityofToronto,Canada,withayearofstayattheUniversityofCambridge

•  Post-docatIPGParis,twoyears•  JoinedtheUniversityCambridgein1990•  Ledthecrea3onofLITHOSgroup•  MovedtoParisin1999(keepingtheposi3oninCambridge)

•  Ledthecrea3onofMarineGeosciencesDepartmentattheIPGParis

CVmaFers:Sa3shSingh-2By2012

•  Published125papersinpeerreviewedjournals,10inScienceandNature

•  Supervised27PhDstudentsandwassupervising10•  Supervised25post-docs•  2009Dis3nguishedLecturerfortheEuropeanAssocia3onofGeoscien3stsandEngineers

•  2009LaureateoftheFrenchMinistryofResearchinScien3ficInnova3onandCrea3on

•  ElectedFellowoftheAmericanGeophysicalUnionin2010

•  AwardedGrandPrixoftheFrenchAcademyofSciencesin2011

IdeamaFersIn2011IhadtwoideasIdea1

•  ApplytheideaIhaddeveloptostudytheSumatrasubduc3onzoneandapplytoJavasubduc3onzone,whichcanproduceadevasta3ngearthquakeandtsunamioffshoreJava

IdeamaFersIdea1

•  Ihaddonefivemarineexperiments,includingtwofundedbyindustry(SchlumbergerandCGG)usingthestateofthearttechnology.

•  Hadover30,000kmofseismicreflec3ondatafromtwoothercompanies(PGSandTGS)

•  Hadpublishedover20papersinpeerreviewedjournals,includingtwoinNatureGeoscience

•  Supervised4PhDstudentsandfivemasterstudents

IdeamaFersIdea1

•  TherewasacryingneedfromIndonesiatostartthisproject

•  Importantscien3ficproblem,wellproven,butnotthatoriginal

Gotfundedin2017(3.5m$)

IdeamaFersIdea2

•  Therewas(s3llis)adebateaboutthenatureofthelithosphere-asthenosphereboundary(LAB),atthebaseofthetectonicplate

•  Isitasharpboundary(500m)orthick(30-100km)transi3onzone?

•  Doesthisboundarydeepenswiththeageofthelithosphere(from3-5kmatoceanspreadingcentreto100kmat100Ma)

•  Exis3ngmethodsdonothavetheresolu3ontosolvethisproblem

IdeamaFersIdea2

•  IthoughtofusingmyexperiencefromSumatra,whereIhadimaged500mthicklayerat60kmbelowtheseafloorusingindustrytechnology

•  CanIusethistechnologytoimagetheLAB?•  IndustryhadcomeoutwithabeFertechnologythanbefore,whichcanallowmetoimage500mthicklayerat100kmdepth,butthecostwouldbehorrendous

•  Italktoindustryandseeiftheywouldbewillingtohelponthisproject,theysaidtheywouldifavesselhappenstobeinthearea

IdeamaFersIdea2

•  Ihadneverworkedonsuchaproblemnorknewmuchaboutthedebate

•  High-riskHigh-reward,soIoptedforthesecondidea.

Takeyour3me•  PressurefromtheIPGPariswastowritetheproposalin2011

•  Isaidno,Iwanttheideatomature,andwriteagoodproposal,andIdecidedwaitandtogofor2012

•  Compe33onwasveryhigh,globallyandwithintheIPGParis(11candidates)

•  Ispentmostofmy2012summeratScrippsIns3tuteofOceanographylearningabouttheproblem,anddrahingtheproposal

Thinkcarefully•  Myprojectwasveryambi3ous:useallpossiblegeophysicalmethodsatthesameloca3ontoaddressthescien3ficques3ons:(1)seismicreflec3on,(2)seismicrefrac3on,(3)broadbandseismology,and(4)magnetotelluricmethod

•  Iamonlyexpertatseismicreflec3on(mostexpensive)andrefrac3on.

•  IaskedcolleaguesfromSouthamptoniftheywouldbeinterestedinbroadbandseismologyandScrippscolleagueformagetotelluric

Thinkcarefully•  Thetotalcostoftheexperimentwouldbeabout15m€,butwecanonlyaskforamaximumof3.5m€

•  SoIdecidedtofocusontheseismicreflec3on(6m€)andrefrac3on(3m€)partandproposedthattheothertwoexperimentscouldbeconsideredasapiggyback,subjecttofundingfromothersources.

•  Loca3onofexperimentwascrucial:EquatorialAtlan3cbecauseofseismicvesselstransi3ngthisareafromSouthAfrica/AmericatoEurope

Trans-Atlan3cILAB:Dream

•  Ultra-deepseismicreflec3onexperimentusingISOMETRIXsystem

•  Ultra-longoffsetrefrac3onexperiment(70OBS)togetvelocity

•  Tele-seismicusing30BBOS(receiverfunc3onandsurfacewave)

•  40Magnetotelluricdeployment(resis3vity)

•  Fromzeroageto100Maoldoceaniclithosphere

•  EquatorialAtlan3cOceanfor2Dstudy

•  Profilecrossingthefracturezones

•  PresentedatERCin2013

Dreamcometrue•  IgotmyERCAdvancegrantin2013•  UKNa3onalEnvironmentCouncilfundedship3meforthedeploymentofbroadbandseismometers

•  KateRychert(Southampton)wroteanERCStar3ngGrantforbroadbandseismometerpartoftheprojectin2014andgotit.

•  GermanScienceFounda3onfundedpartoftherefrac3onexperiment

•  UnitedStatesNa3onalScienceFounda3onfundedthedeploymentofmagnetotelluricinstruments

•  Wegotallthefundsweneeded

RealityHits•  Contractnego3a3on:Oneyear•  Gelngthevesselsandinstrumentstodotheexperiment,mostimportantlyindustryvesselforseismicreflec3on,specificallyasthecostofpetrolwentdownfrom120$/barrelto50$/barrel

•  Fortunately,wehadaseismicvesselpassingthroughourstudyareainMarch2015.Followingalltheprocedureoftenderingetc.,wewentGhanatoboardthevessel.

•  WefoundthatGhanahasclaimed350milesEEZ,insteadon200milesbefore,andourprofilewaswithinthenewGhana’sEEZlimit.

RealityHits•  Wechangedtheprofilehopingtogostraight,butlaterwelearnedthatthisnewlinewillgothroughthedisputedareaoftheBri3shterritory,AscensionIsland,andhencehastochangeagain.

RealityHits•  Butweenduphavingexcellentdata•  WehavetwoPhDstudentsworkingonthesedataandapaperinNatureGeosciencehasbeenacceptedforpublica3on,afundamentaldiscovery.

Asoftoday•  Seismicreflec3onexperimentcompletedin2015onboardtheSchlumbergerseismicvessel,WesternTrident

•  BroadbandseismometerandmagnetotelluricinstrumentsweredeployedinApril2016andrecoveredinApril2017

•  Thefirstrefrac3onexperimentistakingplacenowontheGermanR/VMariaSMerian

•  Thesecondrefrac3onexperimentisplannedinSeptember-October2018onboardFrenchR/VL’Atlante

Acknowledgements•  ERCAdvancedGranttoSingh(IPGP)•  ERCStartGranttoRychert(NOC)•  UKNERCforship3meforTeleseismicandMTstudy(Harmon,NOC)

•  GermanScienceFounda3onforship3meandrefrac3onstudy(Grevemeyer)

•  USNSFforfundingMTdeployment(Constable,Scripps)

•  Schlumberger(WesternGeco)forprovidingWesternTridentforultra-deepseismicstudy

Surveydetails•  Streamer:12kmlong•  Pressure(3.125m),Az,and

Ay(0.76m)components•  Towat30mwaterdepth•  Numberofstreamers:1•  Source:10170cubicinch•  Shotinterval:50m,62.5m

and75m•  Recordlength:20,25,and

30s•  2200km2Ddata(0-75My)

(A-G)•  600kmAcrossFracture

zones(G-H)•  Changeoflinesdueto350

milesEEZrequirements•  Four3mezones•  Crossingoftheequator

April2015

WesternTrident

BBOBSandMTExperiment

UKNERCship3meERCStartGrantUSNSFforMTFebruary2016toApril2017Rychert+Harmon(Southampton)Constable(Scripps)

Refrac3onstudy:LITHOS

2.LITHOS70OBS0-50MaAfricanplate2017onGermanvessel

Refrac3onstudy1.  SPARC:201860OBS0-25MaGreatFracturezonesL’Atlante

Acknowledgements

•  TheprojectisfundedbyERC,UKNERC,GermanScienceFounda3on,andUSNSF

•  SchlumbergerprovidedIsoMatrixvessel,WesternTrident