Imagingwithsca-eredteleseismicwaves:data,methodandapplica7ontotheHellenicsubduc7onzone
F.D.Pearce1andS.Rondenay1
1Dept.ofEarth,Atmospheric,andPlanetarySciences,MIT
FrederickD.Pearce ModifiedaKerProjectMEDUSAproposal
SubductedCrust
SurfaceSeismics
Seismicimagesoflithosphereandupper-mantlestructureprovidekeyconstraintsonlarge-scaletectonicprocesses
Travel7meTomography
Mo7va7on
Moho
TeleseismicMigra7on
40km
FrederickD.Pearce
Bostocketal.,JGR2001
Teleseismicmigra7onofsca-eredwaves
Objec7ve
FrederickD.Pearce
Data
NorthernLine(NL)
*71events
SouthernLine(SL)
*51events
SS
NS
CTF
FrederickD.Pearce
Method
Rondenay,SurveyGeophysics2009
I)Isolatesca-eredteleseismicbodywaves0
50
050
050
050
050
Time[sec]
1)Alignwavefields
2)IsolateincidentP
3)Isolatesca-eredP,SV,andSH
FrederickD.Pearce
MethodII)Applyteleseismicmigra7onalgorithm
P
*Propaga7onwithina1Dbackgroundmodel*2DGeneralizedRadontransforminversion
FrederickD.Pearce
Rondenay,SurveyGeophysics2009
XSL[km]
Dep
th[km]SLImaging*
Δβ = +/- 5% Δα = +/- 10%
XSL[km]FrederickD.Pearce *Earlyversionofimages,seefinalinPearceetal.,JGR2012
XSL[km]
Dep
th[km]
SLImaging*PS
XSL[km]
PPS
PSSv PSSh
FrederickD.Pearce *Earlyversionofimages,seefinalinPearceetal.,JGR2012
SLLateralVaria7ons*
Dep
th[km]
1T
3T
2T
2T
XSL[km]FrederickD.Pearce *Earlyversionofimages,seefinalinPearceetal.,JGR2012
XSL[km]
Dep
th[km]SLImaging*
SubductedCrust
Con3nentalMoho
Eclogi3za3on
OceanicMoho
Δβfrom-5%(red)to5%(blue)
FrederickD.Pearce *Earlyversionofimage,seefinalinPearceetal.,JGR2012
NLImaging*
XNL[km]
Dep
th[km]
Δβfrom-5%(red)to5%(blue)
SubductedCrust
Con3nentalMoho
FrederickD.Pearce *Earlyversionofimage,seefinalinPearceetal.,JGR2012
Results:NLvs.SL*
MohoContourMapCROPProjectFinee,2005
XST
FrederickD.Pearce *Earlyversionofschema7c,seefinalinPearceetal.,JGR2012
Conclusions
Teleseismicmigra7onprovideshigh-resolu7onimagesoflithosphereandupper-mantlestructure
ImagesfromthewesternHellenicsubduc7onzoneshow
*oceaniccrustbeneathsouthernsegment
*con3nentalcrustbeneathnorthernsegment
*differen7alrollbackbetweenSSandNS
FrederickD.Pearce