Presentation at Seismological Society of America meeting in 2010 by Frederick Pearce

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