Embed Size (px)
Citation preview
SeismogenicdepthofthecrustbeneaththeJapaneseIslandusingJapanUnifiedhIgh-resolu:onrelocatedCatalogforEarthquakes(JUICE)
TomokoE.Yano†1–[email protected]†1–[email protected]†1:Na=onalResearchIns=tuteforEarthScienceandDisasterResillience(NIED),Tsukuba,Japan
Ø ABSTRACT
Ø REFERENCES
Ø CONCLUSIONSANDIMPLICATIONSØ “Japan Unified hIgh-resolu=on relocated Catalog forEarthquakes” (JUICE) contains hypocenters whichrelocated >1.1 million events by double-differencereloca=onmethodfromtheNIEDHi-netcatalogforeventswhichoccurredfromJanuary2001toDecember2012,toadepthof40kmwithin1257gridsquaresinJapan.
Ø Theregionalseismogenicdepthsarees=matedbasedonD95 index derived from the JUICE catalog. And it givesreasonablevalues.
Ø Deep adershocks of the 2016 Kumamoto earthquakeoccurred possibly in the briAle-duc:le transi:on zone,accordingtoourresultscombinedwithheatflowdata
Ø Futurework:• Iden=fying the width of ac=ve faults to model theJapanese3Dcommunityfaultmodel.
• Contribu=ng to hazard assessment and riskmanagement for inland earthquakes possibly occur atdirectlybeneathourci=esandpopulatedareas.
JUICE: InspiredbytheSCECCMEproject,wehavegeneratedahigh-resolu=oncatalog called the “Japan Unified hIgh-resolu=on relocated Catalog forEarthquakes” (JUICE, Yano et al., 2017), which can be used to evaluate thegeometryandseismogenicdepthofac=ve faults in Japan.We relocated>1.1millionhypocentersfromtheNa=onalResearchIns=tuteforEarthScienceandDisasterResilience(NIED)Hi-netcatalogforeventswhichoccurredfromJanuary2001toDecember2012,toadepthof40km.Weappliedarela=vehypocenterdetermina=onmethod to thedata ineachgrid square.En=re Japan isdividedinto 1257 grid squares to parallelize the reloca=on procedure. We used adouble-difference method, incorpora=ng cross-correla=ng differen=al =meswith waveform data as well as catalog differen=al picking =mes. This JUICEcatalog enables us to resolve, in detail, a local seismicity distribu=on for theen=re Japanese Islands. We es=mated loca=on uncertainty by a sta=s=calresamplingmethod,usingJackknifesamples,andshowthattherela=veloca=onuncertaintycanbewithin0.37kminthehorizontaland0.85kminthever=caldirec=onwitha90%confidenceintervalforareaswithgoodsta=oncoverage.Seismogenic depths (applica:on of JUICE): Our es=mated seismogenic depthbasedonD95 index, the cutoffdepthwhere totalof 95%ofeventsoccurredderived from the JUICE catalog, agreewith the lower limit of the hypocenterdistribu=onforrecentearthquakes,suchastheChuetsu(2004,Mj6.8),CentralTomori (2016, Mj 6.6), and Kumamoto earthquakes (2016, Mj 7.3). Theseagreements suggest that the new JIUCE catalog is useful for local studies andes=ma=ngthesizeoffutureearthquakesfortheinlandac=vefaults.
Tanaka(2004)�
Ø DevelopingfaultmodelforJapanIslandsØ Tes=ngJUICEcatalogandshowingapplica=onØ Seismogenicdepthanalysisforac=vefaultspecificstudyusing
JUICEØ DoesD95inferredbyJUICEgiveagoodrepresenta=onforthe
bomomofseismogeniclayer?Ø Canwepredictthefaultwidth(relatestotheeventsize)even
beforeeventhappens?Ø Anyrela=onshipbetweenseismogeniclayerandtemperature
likeScholz(1988)proposed?ExpoundingTanaka(2004)forlocalstudy
Scholz(1988)�
Nuclea1onzone(Seismogeniclayer)�
Bri:le-Duc1letransi1onzone�
300oC
Bri:lezone�
Duc1lezone�450oC
Ø PURPOSE
Ø DATAANDMETHOD
Rou=neeventcatalog
• NIEDHi-netrou=neeventcatalog(N=1,175,672)• 2001-2012• M0-M6.5• 0-40kmindepth
• Arrival=mepicks@sta=ons(N≅1,400;Fig.1)• P&Sphasepicks• P&Swaveformcross-correla=ons
JUICE
• HypoDD(WaldhauserandEllsworht,2000)
• N=1,091,636(~93%recov.;Fig.7)
• 1Dvelocitystructure(Fig.2)
• Gridsquares(N=1,257;Fig.3)
• Weigh=ng&Re-weigh=ngscheme(Table1)
Ac=vefaultspecificlocalstudies
• Applica=onofJUICE• Example:D95(Thecut-offdepthwheretotalof95%ofeventoccurredwithinthedepthcolumn,Fig.4)
D95
• Grid:0.02˚;dGrid:±0.1˚• OnlywhenN≥50eventswithindepthcolumn
• Focusontheknownac=vefaultloca=ons
• Fig.5
Seismogenicdepth
• Verifywithtemperaturedata(Fig.6)• Matsumoto(2007);663pts
• Sakagawa(2005);1099pts
• Depthat250-450˚Ces=matedbyEq.1Method-Temperature�
A�
A’�
D90�D450deg�
D300deg�D250deg�
A� A’�
Depth(km) �
Distance(km)�
- EsAmaAngD250deg,D300deg,andD450deg(followingTanaka
2009)
[TurcoGeandShubert(1982)]- To=13.51˚(AveragetemperatureofgroundsurfacealloverJapan,NaAonalAstronomical
Observatory,1988)
- q0:Heatfluxknowfromdata
- k:ThermalconducAvityknownfromdataifnot2.5Wm-1K-1[Fowler(2005)]
- Z1=10km(ThecharacterisActhicknessofthelayerenrichedinradioacAveelements)
- A=1.4μWm-1K-1(TheaverageheatproducAoninthecrust,Fowler,2005)
- SolveforZwhenT=250,300,and450degrees
Fig.1.Sta=ondistribu=onFig.2.Velocitymodel Fig.3.Gridsquares
Fig.5.D95distribu=on
Eq.1
Fig.4.D95calcula=on
Fig.6.è Temperaturemeasurement
loca=ons&D300deg
(whenT=300˚C)D95
Matsubara,M.andK.Obara(2011)The2011OffthePacificCoastofTohokuearthquakerelatedtoastrongvelocitygradientwiththePacificplate,EarthPlanetsSpace,63,663-667,doi:10.5047/eps.2011.05.018.MatsumotoT(2007)Terrestrialheatflowdistribu=oninJapanareabasedonthetemperatureloggingintheboreholeofNIEDHi-net.In:AGUFallMee=ngAbstracts.Sakagawa,Umeda,Asamori(2005)Heatfluxdistribu=onintheJapaneseislandsconsideringthermaladvec=onandthermalandwatercouplingsimula=onforUnzenVolcano.Nuclearpowerback-endresearchvolume11,issue2.ScholzCH(1988)Thebrimle-plas=ctransi=onandthedepthofseismicfaul=ng.GeolRundschau77:319–328.doi:10.1007/BF01848693TanakaA(2004)GeothermalgradientandheatflowdatainandaroundJapan(II):Crustalthermalstructureanditsrela=onshiptoseismogeniclayer.Earth,PlanetsSp56:1195–1199.doi:10.1186/BF03353340TanakaA(2009)LithosphericThermalStructure :OneofFactorsInfluencingDepthofEarthquakes.Jishin61:239–245.WaldhauserF,EllsworthWL(2000)ADouble-differenceEarthquakeloca=onalgorithm:Methodandapplica=ontotheNorthernHaywardFault,California.BullSeismolSocAm90:1353–1368.doi:10.1785/0120000006YanoTE,TakedaT,MatsubaraM,ShiomiK(2017)JapanUnifiedhIgh-resolu=onrelocatedcatalogforearthquakes(JUICE):CrustalseismicitybeneaththeJapaneseIslands.Tectonophysics702:19–28.doi:10.1016/j.tecto.2017.02.017
ResilienceResilience
2017AnnualMee=ng
Ø RESULTSFig.8.(a)and(b):Histogramsofstandard devia=ons (in blue forjackknifetestinRegions1and2,goodandbadsta=oncoverage).Ø Uncertainty(90%confidencelimit)
-Goodsta=oncoverage-Horizontal:0.37km-Ver=cal:0.83km-Badsta=oncoverage-Horizontal:1.21km-Ver=cal:1.58km(c):Histogramsoftherootmeansquare (rms) of the travel =meres iduals for the or ig inalhypocenter catalog (ini=al rms)and for the JUICE hypocentercatalog(finalrms)Ø Fittothedata(AllJapan)-Before0.087s(Hi-netro=ne)-Ader0.058s.(JUICE)
Fig.9Thebluerectangleindicatestheareawithin±0.2°ofthegridboundary.Theaveragedifferenceindepthfortherelocatedhypocentersbetweenthetwotestregionsis0.1kmver=caland0.2kmhorizontalcomponents.Ø Possibleoffsetaffectedby
griddingisrela=velysmall.Ø However,usershouldpay
amen=ontotheedgeofgridifthereareanysharpoffsetofseismicity.
Fig7.JUICEcatalog,containshypocenters(M≦6.5)relocatedbyaDDalgorithm(Waldhauser&Ellsworth,2000)for1,091,636eventsofM≦6.5thatoccurredbetweenJanuary2001andDecember2012,atdepthsshallowerthan40km.Thegreenlinesaretheknownac=vefaults(theResearchGroupforAc=veFaultsofJapan,1991).NOTE:ThisfigureonlyshowsJUICEcatalogwithdepth≤20kmforeasiertograspsometrends.
Results�
1.Lowerlimitofseismogenicdetphvs.
Seismicity(hypocenter/a=ershocks)
Above/Above2.vs.mainslip
Above3.Vp/Vs
1.7~1.754.ParturbVp
-4~2%�
2.Seismicityw.r.t.D95
(hypocenter/a=ershocks)
Above/Below(5km) �
D95�2016KumamotoEq.�
Depth(km) �
Distance(km)�
B’�
B�
B�
B’�
B� B’�
D95�D450deg�D300deg�D250deg�
D300deg�
Ø Vp/Vs:1.6–1.8;Vp:5.9–6.8km/saroundthedeepestboundaryofseismogenicdepthØ Mainshocks,adershocks,andmainco-seismicsliplocateabovetheD95
Ø D95duetoJUICEisquitegoodindextoes=matethelocalseismogenicdepth.Ø Deepadershocksinthecaseofthe2016Kumamotoeq.mightoccurred@brimle-duc=le
zone,b/cintheorangecircle,Ø Vp/Vs:~1.7;Vp:~7.4km/s(Vpisextremelyfaster)Ø 300˚C–450˚C(accordingtoScholz’sdiagram)
Distance(km)�
Depth(km) �
D95�D450deg�
D95�D450deg�
D300deg�
D300deg�
?
?
êDeepadershocks(orangecircle)ofthe2016Kumamotoeq.
JUICE(Yanoetal.,2017)
SeismogenicdepthApplica=on
Results�
B’�
B�
B�
B’�
1. D95andD250-450deg15(SW)�10(NE)km/30(SW)�10(NE)km
2.Seismicityw.r.t.D95(hypocenter/aCershocks)
Above/Above3.Mainslipw.r.t.D95
Above4.VelocitystructurealongD95(Vp/Vs&Vp)
1.6–1.75&6.0–6.3km/s �
2016KumamotoEq.�
Depth(km) �
Distance(km)�
B� B’�
D95�D450deg�D300deg�D250deg�
D95�
D300deg�
Results�
1.Lowerlimitofseismogenicdetphvs.
Seismicity(hypocenter/a=ershocks)
Above/Above2.vs.mainslip
Above3.Vp/Vs
1.7~1.754.ParturbVp
-4~2%�
2.Seismicityw.r.t.D95
(hypocenter/a=ershocks)
Above/Below(5km) �
D95�2016KumamotoEq.�
Depth(km) �
Distance(km)�
B’�
B�
B�
B’�
B� B’�
D95�D450deg�D300deg�D250deg�
D300deg�
1. D95andD250-450deg15(SW)�10(NE)km/30(SW)�10(NE)km
2.Seismicityw.r.t.D95(hypocenter/a>ershocks)
Above/Above3.Mainslipw.r.t.D95
Above4.VelocitystructurealongD95(Vp/Vs&Vp)
1.6–1.75&6.0–6.3km/s �
1. D95andD250-450deg15(SW)�10(NE)km/30(SW)�10(NE)km
2.Seismicityw.r.t.D95(hypocenter/a>ershocks)
Above/Above3.Mainslipw.r.t.D95
Above4.VelocitystructurealongD95(Vp/Vs&Vp)
1.6–1.75&6.0–6.3km/s �Depth(km)
Distance(km) Kubo et al. 2016
B B’
1. D95andD250-450deg15(SW)�10(NE)km/30(SW)�10(NE)km
2.Seismicityw.r.t.D95(hypocenter/a>ershocks)
Above/Below5km3.Mainslipw.r.t.D95
Above4.VelocitystructurealongD95(Vp/Vs&Vp)
1.6–1.75&6.0–6.5km/s �
1. D95andD250-450deg15(SW)�10(NE)km/30(SW)�10(NE)km
2.Seismicityw.r.t.D95(hypocenter/a>ershocks)
Above/Below5km3.Mainslipw.r.t.D95
Above4.VelocitystructurealongD95(Vp/Vs&Vp)
1.6–1.75&6.0–6.5km/s �
2004Chuetsu� 2007Chuetsu-Oki�
2007Noto� 2016To5ori� 2016Kumamoto�
1.D90/95[km]� 17-22(D95)� 25-30(D90)� 10(D90)� 14(D95)� 10-15(D95)�
D250deg-D450deg[km]�
SW� NE� 7-15� 4-14� 5-14� SW� NE�
3-7� 10-22� 8-30� 3-10�
2.Seismicity(mainshock/aMershocks)�
Above/mainlyabove�
Above/above�
On/above� Above/above� Above/below5km�
3.Mainslipdepth�
Above� Above� Above� Above� Above�
4.Vp/Vs� 1.7~1.8� 1.75~1.8� 1.6~1.75� 1.6~1.75� 1.6~1.75�
Vp(km/s)� 6.5~6.8� 6.7~6.8� 5.9~6.3� 6.0~6.3� 6~6.5�
2004Chuetsu(M6.8)
2007Chuetsu-Oki(M6.8)
2007Noto(M6.9)
2016C.Tomori(M6.6)
2016Kumamoto(M7.3)
Depth(km) �
Distance(km)�
B� B’�
Vp/Vs(MatsubaraandObara.,2011)�
Vp(MatsubaraandObara.,2011)�
