by Zhiqin Xu , Shaocheng Ji Uplift of the Longmen Shan

The 12 May 2008 Wenchuan earthquake (Ms=8.0)struck on the Longmen Shan foreland thrust zone. Theevent took place within the context of long-term uplift ofthe Longmen Shan range as a result of the extensiveeastward-extrusion of crustal materials from theTibetan plateau against the rheologically strong crust ofthe Sichuan Basin. The Longmen Shan range is charac-terized by a Pre-Sinian crystalline complex constrainedby the Maoxian-Wenchuan-Kangding ductile detach-ment at the western margin and the Yingxiu-Beichuan-Luding ductile thrust at the eastern margin. The Long-men Shan uplift was initiated by intracontinental sub-duction between the Songpan-Ganzi terrane and theYangtze block during the Pre-Cenozoic. The uplift ratewas increased considerably by the collision between theIndian and Eurasian plates since ~50 Ma. TheWenchuan earthquake resulted in two major NE-strik-ing coseismic ruptures (i.e., the ~275 km long Yingxiu-Beichuan-Qingchuan fault and the ~100 km long Anx-ian-Guanxian fault). Field investigations combined withfocal solutions and seismic reflection profiles suggestthat the coseismic ruptures are steeply dipping close-to-pure reverse or right reverse oblique slip faults in the~15 km thick upper crust. These faults are unfavorablyoriented for frictional slip in the horizontally compres-sional regime, so that they need a long recurrence interval to accumulate the tectonic stress and fluid pres-sure to critically high levels for the formation of strongearthquakes at a given locality. It is also found that all the large earthquakes (Ms>7.0) occurred in the faultzones across which the horizontal movement velocitiesmeasured by the GPS are markedly low (<3 mm/yr). The faults, which constitute the northeastern fronts ofthe enlarging Tibetan plateau against the strongSichuan Basin, Ala Shan and Ordos blocks, are verydestructive, although their average recurrence intervalsare generally long.

Introduction

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Episodes, Vol. 31, No. 3

Articles 291

by Zhiqin Xu1, Shaocheng Ji2, Haibing Li1, Liwei Hou3, Xiaofang Fu3, and Zhihui Cai1

Uplift of the Longmen Shan range and theWenchuan earthquake$#e-(#H'X80'/80(#89#>8"/3"-"/'G#[("':32.+#&3"3./0(#89#H'",#'",#f-.8102-.d#^"./3/1/-#89#F-8G8;(+#>53"-.-#@2',-:(#89#F-8G8;32'G#E23-"2-.d#U-3V3";#$)))PA+#>53"'<#E-mail: xzq@ccsd.cn

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September 2008

292

Figure 1 A simplified geological map of the Longmen Shan range and its adjacent areas. K&N_#K-"251'"=&'8`3'"#9'1G/d##bUN_#b3";`31=U-3251'"#9'1G/d##F@N_#F1'"`3'"=@"`3'"#9'1G/d##IgN_#I3";C1=g3";251'"#9'1G/d##]EhN_#]3'".5135-#9'1G/dHgEN_##H8";61'"#E5'"#9'1G/<###^".-/_#f-;38"'G=.2'G-#.-//3";#89#/5-#H8";:-"#E5'"#0'";-#X-/C--"#/5-#E8";L'"=F'"a3#/-00'"-#'",#/5-#b'";/a-#XG827<

Figure 2 GPS velocities in and around the eastern Tibetan plateau with respect tostable Eurasia. (After Zhang et al., 2004) f-,#,8/._#-'0/561'7-.#M&#! A<)O<##^".-/_#f-;38"'G=.2'G-#.-//3";#89#J3X-/'"#IG'/-'1<#@HJN_#@G/("J';5#9'1G/d#?eHN_#?'./#e1"G1"#9'1G/d#H&EN_#H8";:-"#E5'"#N'1G/d#]EhN_#]3'".5135-#9'1G/<

Tectonic setting of the Longmen Shan

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The complex belt of the Longmen Shan crystallinebasement

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a832# 48G2'"32# 0827.# '",# ;0'L53/-#:'0XG-+# /5-# E3"3'"=E3G103'"# 28"=;G8:-0'/-+# .3G/3/-+# .G'/-# '",# .3G32'G3/-+# /5-#>'0X8"39-081.# /8# G8C=/8=:3,#J03'..32#G3:-./8"-#'.#C-GG#'.#/5-#1LL-0#J03'..32#28'G#./0'/'+#'GG84-0G'L#8"#/5-#8G,-0#28:LG-`<

The Longmen Shan foreland thrusting wedgeE-3.:32#G3"-.#'208..#/5-#H8";:-"#E5'"#ME8";#-/#'G<+#$B*Bd#l3'

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Episodes, Vol. 31, No. 3

293

Figure 3 Tectonic map and cross sections of the Longmen Shan and adjacent areas.

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>-"8a832# 28:LG-/-# ./0'/'# .-61-"2-# C3/5# '# X1G7# /5327"-..# 89S+)))–$%+)))#:<# J5-#DLL-0# J03'..32–g1'/-0"'0(# ./0'/'# '0-# 28"/3="-"/'G#,-L8.3/.#C3/5#/5327"-..-.#89#$+W))–P+)))#:+#%+)))–W+)))#:+T%+)))#:#'",#T$+$))#:#980#/5-#1LL-0#J03'..32+#l10'..32+#>0-/'2-81.+'",#>-"8a832+#0-.L-2/34-G(<#J5-#2G'./32#0827.#89#/5-#E3251'"#U'.3"3"2G1,-#28";G8:-0'/-#'",#28'G#./0'/'#C3/5#'#X1G7#/5327"-..#89#.-4-0'G/581.'",#:-/-0.+#5'43";#'221:1G'/-,#,103";#/5-#-",#89#/5-#H'/-#J03='..32<# >8".3,-03";# /5-# H8C-0=&3,,G-# l10'..32# ./0'/'# 84-0G'LL3";1"28"980:'XG(#1L8"# /5-# 980-G'",#X80,-0#89# /5-# /501./+#C-#.1;;-.//5'/#/5-#:8G'..-.#980:-,#908:#/5-#-",#89#/5-#G'/-#J03'..32#/8#l10'..32'.#'#0-.1G/#89#/5-#980-G'",#X'.3"#89#/5-#E8";L'"=F'"a3#808;-"32#X-G/<J5-#./0'/'#89#/5-#G'/-#&-.8a832=?82-"-#.-03-.#5'4-#'"#'221:1G'/-,/5327"-..#89#P+Z))#:+#C3/5# .-4-0'G#;081L.#89#:8G'..-.#,-4-G8L-,<J5-.-# :8G'..-.# '0-# -61'GG(# 25'0'2/-03./32# 89# /5-# 980-G'",# X'.3"<E3"2-#/5-#>-"8a832#98G,.#'",#/501./#./012/10-.#5'4-#,-4-G8L-,#3"#/5-980-G'",#X'.3"#,1-# /8# /5-#RK=E?=803-"/-,# 28:L0-..38"<#J5-(# '0-G3"7-,#/8#/5-#G'/-0'G#-`/01.38"#89#201./'G#:'/-03'G.#908:#/5-#-'./-0"J3X-/'"#LG'/-'1<#J5-#X'.-:-"/#89#/5-#E3251'"#980-G'",#X'.3"#3.#28:=L8.-,# :'3"G(# 89# ;0'"3/-# '",# ,-GG-"3/-+# /5-# fX=E0# C58G-=08273.82508"#';-.#89#C5325#'0-#AZ$#&'#'",#A)%#&'+#0-.L-2/34-G(<#J5-.-';-.# '0-# 28:L'0'XG-# /8# /58.-# 89# /5-#H8";:-"E5'"#20(./'GG3"-#28:LG-`<#

The Songpan-Ganzi terraneJ5-# E8";L'"=F'"a3# /-00'"-# 3.# '# J03'..32

808;-"32#X-G/+#,3.LG'(3";#'#/03'";G-#.5'L-+#$+)))7:#C3,-#3"#/5-#RE#,30-2/38"#'",#%+)))#7:#G8";3"#/5-#?K#,30-2/38"<#J53.#/-00'"-#3.#X81",-,#X(/5-#?'./#e1"G1"#/-00'"-#3"#/5-#"80/5+#/5-#g3'";=/'";#/-00'"-#3"#/5-#.81/5C-./+#'",#/5-#H8";:-"E5'"# 0'";-# 3"# /5-# -'./<# J5-# 980:'/38"# 89# /53.808;-"32#X-G/#C'.#0-G'/-,#/8#/5-#2G8.10-.#89#/5-e1"G1"=@"3:'63"# 82-'"32# X'.3"# 3"# /5-# "80/5'",#/5-#l3".5'V3'";#I'G-8/-/5(.#82-'"32#X'.3"#3"/5-# .81/5C-./+# '",# /8# /5-# 28GG3.38"# ':8";# /5--'./-0"#e1"G1"#/-00'"-+#/5-#E8";L'"=F'"a3#/-0=0'3"#'",#/5-#g3'";/'";#/-00'"-#,103";#/5-#1LL-0J03'..32<#J5-#E8";L'"=F'"a3#808;-"32#X-G/#C'.899.-/#*)–B)#7:#X(#/5-#RK=E?=/0-",3";+#]3'"=.5135-#G-9/=G'/-0'G#./037-=.G3L#9'1G/#,103";#/5-#G'./%)#&'_# /5-#R?# L'0/# X-3";# /5-#['"X'# /-2/8"321"3/# '",# /5-# EK# L'0/# X-3";# /5-#&1G3# /-2/8"321"3/#M]1#-/#'G<+#$BBSO<#U8/5#1"3/.#5'4-#'#:-/'=:80L532#X'.-:-"/#.3:3G'0#/8#/5-#H8";:-"#E5'"20(./'GG3"-# 28:LG-`# 3"# /-0:.# 89# X8/5# G3/58G8;('",#980:'/38"#';-<#

Pre-Cenozoic LongmenShan extrusion structure

@#,12/3G-#/501./#a8"-#,3LL3";#./--LG(#/8#/5-#C-./G3-.#X-/C--"#/5-#H8";:-"#E5'"#20(./'GG3"-#28:=LG-`#'",#/5-#R-8=I08/808a832#:-/'48G2'"32#0827.'X84-#'",#8"#/5-#-'./-0"#:'0;3"#89#/5-#H8";:-"E5'"<# U03//G-# ,-980:'/38"# 84-0L03"/-,# 8"# /5--'0G(# ,12/3G-# /501./3";# 980:-,# /5-# .8=2'GG-,b3";`31=U-3251'"#/501./#9'1G/#3"#/5-#L0-.-"/=,'(201./#'X84-#/5-#,12/3G-=X03//G-#/0'".3/38"#a8"-<#@//5-#RK#:'0;3"#89#/5-#28:LG-`+#'#,12/3G-#,-/'25=:-"/#M3<-<+-`/-".38"'G#.5-'0#a8"-O#,3LL3";#./--LG(/8#/5-#C-./#X-/C--"#/5-#28:LG-`#'",#3/.#284-0.#3.25'0'2/-03a-,#X(#:(G8"3/3a'/38"#'",#3"/-".-#LG'.=/32#.5-'0#./0'3"#C3/5#/8L=/8=C-./#.5-'0#.-".-#3",3=2'/80.<#J53.#,12/3G-#,-/'25:-"/#C'.# 0-'2/34'/-,

'.# /5-# X03//G-#K-"251'"=&'8`3'"# /501./# 9'1G/# ,103";# /5-# >-"8a832<!X4381.G(+#/5-#H8";:-"#E5'"#28:LG-`#'2/-,#3"3/3'GG(#'.#'"#-`/01.38"./012/10-# ,103";# /5-# >0-/'2-81.# 28:L0-..38"+# X-2'1.-# /5-# ,12/3G-,-/'25:-"/#M1LL-0#X81",'0(O#822100-,#'/#/5-#C-./-0"#:'0;3"#C5-0-'./5-#,12/3G-#/501./#822100-,#'/#/5-#-'./-0"#:'0;3"#MG8C-0#X81",'0(O<

Ductile detachment at the northwestern margin ofthe Longmen Shan

J5-# ,12/3G-# ,-/'25:-"/# '/# /5-# "80/5C-./-0"# :'0;3"# 89# /5-H8";:-"# E5'"# -`/-",.# 908:# /5-# C-./-0"# I-";;1'"# 28:LG-`+/5081;5#/5-#C-./-0"#U'8`3";#28:LG-`+#'",#"'GG(#/8#/5-#e'";,3";28:LG-`<#F-"-0'GG(#/5-#,-/'25:-"/#,3L.#./--LG(#/8#/5-#C-./<#^"#/5-"80/5C-./-0"#I-";;1'"#28:LG-`#'",# /5-#"80/5-0"#e'";,3";#28:=LG-`+#58C-4-0+#3/#,3L.#;-"/G(#/8#/5-#"80/5#80#/5-#"80/5C-./<

^"# /5-#K-"251'"=F-";,'# '0-'# '/# /5-# C-./-0"# :'0;3"# 89# /5-I-";;1'"=U'8`3";# ;0'"8,3803/32# 28:LG-`+# /5-# 3"/-".-G(# ,-980:-,'",#/53""-,#R-8L08/-08a832#:-/'48G2'"32#0827.#'",#/5-#!0,84323'"–E3G103'"#-L3a8"'G#:-/':80L532#./0'/'#84-0G'L#8"# /5-#28:LG-`<#J5-,12/3G-#,-/'25:-"/#X-/C--"#/5-#28:LG-`#'",#3/.#284-0.#3.#25'0'2/-0=3a-,#X(#98G3'/38"#,3LL3";#./--LG(#/8#/5-#C-./+#,3L=.G3L#./0-/253";#G3"=-'/38"#'",#:(G8"3/3a'/38"#MN3;10-#ZO<#!"#/5-#LG'"-#L'0'GG-G#/8#/5-#G3"=

September 2008

294

Figure 4 Photographs showing outcrops of the ductile detachment at the western andnorthern margins of the Longmen Shan complex.

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MXO# J5-# ,-/'25:-"/# ,-4-G8L-,# 3"#:-/'48G2'"32# '",# ;0'"3/32#:(G8"3/-.# '/# /5-#C-./-0"#:'0;3"# 89# /5-e'";,3";#28:LG-`<###

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2'"32#:(G8"3/-#3"#/5-#,12/3G-#/501./#'/#/5-#-'./-0"#:'0;3"#89#/5-#e'";,3";#28:LG-`<#

-'/38"#'",#L-0L-",321G'0#/8#/5-#98G3'/38"#M3<-<+#/5-#]k#LG'"-O+#!= '","=.5'L-,#'.(::-/032#9-G,.L'0#80#61'0/a#L80L5(082G'./.#3",32'/-#28"=.3./-"/G(#'#/8L=/8=C-./#.5-'0#.-".-#MN3;10-#WO<#H'//32-=L0-9-00-,#803=-"/'/38".#MHI!.O#89#61'0/a#908:#4-#/(L32'G#;0'"3/32#:(G8"3/-.#'",L5(GG8"3/-.# M.':LG-.# H&]A=%+# H&]# P+# H&]# *+# H&]# $$# '",#H&]# $PO+# :-'.10-,# 1.3";# /5-# -G-2/08"# X'27.2'//-0# ,3990'2/38"M?UE[O# /-25"361-.# MN3;10-# S'O+# 3",32'/-# /5'/# 61'0/a# ,-980:-,# X(,3.G82'/38"#;G3,-#1.3";#.G3L#.(./-:#4'0(3";#908:#m$)n$)oj'p+#/5081;5##m$)n$$oj'p+#'",#"'GG(#/8#m)))$oj'p<#J5-#9'X032#-48G1/38"#.1;;-././5'/# /5-#,-980:'/38"# /-:L-0'/10-#4'03-,# 908:#-'0G(#:8,-0'/-# /-:=L-0'/10-#MTWW)c>O#/8#G'/-#G8C#/-:L-0'/10-#MTPW)c>O<#J5-#HI!#'.(:=:-/0(#C3/5#0-.L-2/#/8#/5-#./012/10'G#90':-C807#M]=b=kO#,3.LG'(.#'/8L=/8=/5-="80/5C-./#.5-'0#.-".-<

J5-#"80/5-0"#L80/38"#89# /5-#e'";,3";#28:LG-`#-`L8.-,# 3"# /5-e8";(1=&3";'3#'0-'# 3.#84-003,,-"#X(# 3"/-".34-G(#.5-'0-,#R-8=I08=/-08a832# :-/'48G2'"32# 0827.# C3/5# 80# C3/581/# /53""-,# k=E# -L3a8"'G:-/':80L532#./0'/'<#J5-#,12/3G-#,-/'25:-"/#3.#28:L8.-,#89#;0'"3/32:(G8"3/-# '",# L5(GG3/-#C3/5# 98G3'/38"# ,3LL3";# ;-"/G(# /8C'0,.#RRK+

"-'0G(#RE='G3;"-,#./0-/253";#G3"-'/38"+#@=/(L-#98G,.#'",#.5-'/5#98G,.<f8/'/-,#G3:-./8"-#XG827.#MX81,3".O#'",#!=.5'L-,#61'0/a#L80L5(082G'./.3"#/5-#E3G103'"#L5(GG3/-#3",32'/-#/5-#/8L=/8="80/5#.5-'0#MN3;10-.#Z+#WO<

J5-#F-a8";#28:LG-`+#C5325#G3-.#$*#7:#/8#/5-#"80/5#89#e8";(1+3.#28:L8.-,#89#;0'"8,3803/-#MD=IX#a3028"#';-#3.#AA$#&'+#.3:3G'0#/8/5'/#89#/5-#e'";,3";#28:LG-`O<#J5-#/53""-,#'",#,-980:-,#R-8L08=/-08a832# :-/'48G2'"32# 0827.# '",# /5-# E3"3'"=E3G103'"# -L3a8"'G#:-/':80L532#0827.#M-<;<+#28";G8:-0'/-#'",#;0'4-G#L5(GG3/-O#284-0-,/5-#28:LG-`#C3/5#'"#3"/-09'2-#89#:(G8"3/3a'/38"<#J53.#,12/3G-#,-/'25=:-"/# V83".# .81/5C'0,# C3/5# /5'/# '/# /5-# "80/5-0"# :'0;3"# 89# /5-e'";,3";#28:LG-`#MN3;10-.#$+#%O<#g1'0/a#HI!.#908:#W#L5(GG8"3/-.':LG-.+#':8";#C5325#/50--#MH&]$A=$+#H&]$A=%#'",#H&]$A=ZOC-0-#28GG-2/-,# 908:# /5-#e8";(1#'0-'# M3<-<+# /5-#"80/5-0"#e'";,3";28:LG-`O# '",# /C8# MH&]$Z=$# '",# H&]$Z=%O# 908:# /5-# .81/5-0"F-a8";# 28:LG-`+# C-0-# :-'.10-,# 1.3";# /5-# ?UE[# /-25"361-.<#J5-#9'X032#0-.1G/.#MN3;10-#SXO#0-4-'G#/5'/#/5-#L0-4'3G3";#,3.G82'/38".G3L# .(./-:# 4'03-,# 908:# m$)n$)oj'p+# /5-"# m$)n$$oj'p+# "'GG(# /8m)))$oj'p#MTWW)c>–PW)c>O#980#/5-#"80/5-0"#e'";,3";#28:LG-`+#'",

Episodes, Vol. 31, No. 3

295

Figure 5 Microphotographs showingshear deformation in the ductiledetachment along the western andnorthern margins of the Longmen Shancomplex.

M'O#f8/'/38"'G#61'0/a#L80L5(082G'./.# Mg/aO# '",9-G.32#';;0-;'/-.#MN.Lqg/aO#M.':LG-#H&]=A=*O# .58C3";# '# /8L=/8=C-./# .5-'0# 908:# ':-/'48G2'"32# :(G8"3/-# M:'/03`# 3.# 28:=L8.-,#89#61'0/a+#9-G,.L'0+#25G803/-#'",#:1.=2843/-O# '/#F-";,'# M/5-#C-./-0"#:'0;3"# 89/5-#I-";;1'"#28:LG-`O<#

MXO# I0-..10-# .5',8C# 89#F'0"-/# L80L5(082G'./.908:# L5(GG8"3/-# M:'/03`# 3.# 28:L8.-,# 89:(G8"3/32# 61'0/a+# 9-G,.L'0+# 25G803/-# '",:1.2843/-O#M.':LG-#H&]=$Z=$O#.58C3";#'/8L=/8=-'./#.5-'0#'G8";#/5-#"80/5-0"#:'0;3"89#/5-#e'";,3";#28:LG-`<#

M2O f8/'/38"'G# 61'0/a# L80L5(082G'./.# 908:;0'"3/32# :(G8"3/-# M:'/03`# 3.# 28:L8.-,# 8961'0/a+# 9-G,.L'0# '",# :1.2843/-O# M.':LG-H&]=%$=$O# .58C3";# '# /8L=/8=-'./# .5-'0'G8";#/5-#C-./-0"#:'0;3"#89#/5-#e'";,3";28:LG-`<

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M9–;O#f8/'/38"'G#61'0/a#'",#9-G,.L'0#L80L5(08=2G'./.#3"#;0'"3/32#:(G8"3/-.#M:'/03`#3.#28:=L8.-,# 89# 9-G,.L'0+# 61'0/a+# :1.2843/-# '",X38/3/-O#M.':LG-.#H&]=%Z=S#'",#H&]=%Z=*O#908:#H1,3";#3",32'/-#'#/8L=/8=-'./#,12=/3G-# /501./# .5-'0# 980# /5-# -'./-0"#:'0;3"# 89/5-#e'";,3";#28:LG-`<

908:#m$)n$)oj2p#/8#m$)n$)oj'p#/5-"#/8#m$)n$$oj'p#MTSW)c>–ZW)c>O980# /5-# .81/5-0"# F-a8";# 28:LG-`<# J5-# 61'0/a# 9'X032# '.(::-/0((3-G,.#28".3./-"/G(#/5-#.':-#.5-'0#.-".-_#/8L#/8#/5-#"80/5C-./<

J5-#,12/3G-#,-/'25:-"/#X-/C--"#/5-#e'";,3";#28:LG-`#'",#/5-:-/'48G2'"32#0827.#,3L.#:80-#./--LG(#C-./C'0,<#!=.5'L-,#9-G,.L'080#61'0/a#L80L5(082G'./.#3"#/5-#;0'"3/32#:(G8"3/-#"-'0#/5-#e'";,3";X1.#./'/38"#3",32'/-#'#/8L=/8=C-./#.5-'0#.-".-#MN3;10-.#Z+#WO<#J50--:(G8"3/-.# M.':LG-.# H&]=%$=$+# H&]=%$=%+# H&]=%$=PO# 908:# /5-I'8:'#E5'"#'/#/5-#C-./-0"#:'0;3"#89#/5-#e'";,3";#28:LG-`#C-0-28GG-2/-,# 980# /5-#?UE[#:-'.10-:-"/#89#61'0/a#HI!.# MN3;10-#S2O<#[3.G82'/38"# .G3L# .(./-:.# '0-# 3"9-00-,# /8# ,3.LG'(# '# /0'".3/38"# 908:#m$)n$)oj2p#/8#m$)n$$oj'p<#J5-#9'X032#-48G1/38"#3",32'/-.#'#25'";-#3",-980:'/38"#/-:L-0'/10-#908:#TSW)c>#/8#TZW)c><#J5-#HI!#'.(:=:-/0(#(3-G,.#'#/8L=/8=C-./#.5-'0<

The Yingxiu-Beichuan ductile thrust at the easternmargin of the Longmen Shan complex

J5-#U-3251'"=b3";`31#,12/3G-#/501./+#C5325#G3-.#X-/C--"#/5-#-'./=-0"#:'0;3"#89# /5-#H8";:-"#E5'"#28:LG-`#'",# /5-#R-8=I08/-08a832:-/'48G2'"32#0827.+#3.#:'07-,#X(#'#%))–P))#:#/5327#X-G/#89#;0'"3/32'",#:-/'48G2'"32#:(G8"3/-.<#J5-#:(G8"3/32#98G3'/38"#,3L.#,--LG(#/8/5-##C-./<#E=>#./012/10-.#'",#L80L5(082G'./#.(./-:.#8"#/5-#]k#LG'"-3",32'/-#'#/8L=/8=-'./#.5-'0<##HI!.#89#61'0/a#908:#W#:(G8"3/-#.':=LG-.#MH&]%Z=%+#H&]%Z=P+#H&]%Z=W+#H&]%Z=*+#H&]%Z=$)O#28G=G-2/-,# 908:#H1,3";63'8+# -'./-0"#:'0;3"#89# /5-#e'";,3";#28:LG-`#MN3;10-# S,O+# .1;;-./# '# .G3L# .(./-:# /0'".3/38"# 908:# m$)n$)oj'p#➝m$)n$$oj'p#➝ m)))$oj'p#MTWW)c>–PW)c>O#'",#'#/8L=/8=-'./#.5-'0.-".-<

September 2008

296

Figure 6 LPO's of quartz from themylonites of the ductile detachment andductile thrust, measured using the EBSDtechniques.

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MXO# E':LG-.# H&]=$A=%# '",# H&]$A=Z# 908:e8";(1# '/# /5-# "80/5-0"# -,;-# 89# /5-e'";,3";#28:LG-`+#'",#.':LG-.#H]&$S=WML5(GG3/32# 28";G8:-0'/-O+# H]&$S=AM;0'"3/32# :(G8"3/-O# '",# H&]$Z=$# '",H&]$Z=%# M;'0"-/=X-'03";# 61'0/a# .253./O908:#F-a8";#'/#/5-#"80/5-0"#:'0;3"#89#/5-e'";,3";#28:LG-`<#

M2O# E':LG-.# H&]%$=$+# H&]%$=%+# '",# H&]%$=P#908:#I'8:'#E5'"#'/#/5-#C-./-0"#:'0=;3"#89#/5-#e'";,3";#28:LG-`<#

M,O#E':LG-.#H&]%Z=%+#H&]%Z=*+# '",#H&]=%Z=$)O#908:#H1,3";63'8#'/#/5-#-'./-0"#-,;-89#/5-#e'";,3";#28:LG-`<#]#'",#k#'0-#L'0='GG-G# /8# G3"-'/38"# '",# "80:'G# /8# 98G3'/38"+0-.L-2/34-G(<# R_# "1:X-0# 89# :-'.10-:-"/L83"/.<#&3"<#[# '",#&'`<#[# 0-L0-.-"/# /5-:3"3:1:#'",#:'`3:1:#,-".3/3-.+#0-.L-2=/34-G(<

40Ar/39Ar ages of the Longmen Shanductile detachment

JC8#.':LG-.#MH&]=$Z=%+#H&]=$Z=PO#C-0-#28G=G-2/-,#908:#/5-#:-/'48G2'"32#:(G8"3/-.#89#/5-#,12/3G-,-/'25:-"/#'/#/5-#.81/5-0"#:'0;3"#89#/5-#F-a8";#28:=LG-`#980#X38/3/-#Z)@0iPB@0#,'/3";#MJ'XG-#$#'",#N3;10-AO<#J5-#/8/'G#';-#89#$%#/-:L-0'/10-#./';-.#3.#$$B<Z#&'<R3"-#:8,-0'/-#'",#53;5#/-:L-0'/10-.#./';-.#X-/C--"B))c>#'",#$+Z))c>#,3.LG'(#'#'/#LG'/-'1#';-#MJLO#89$%$<Wr$<)#&'+#C5325# 2800-.L8",.# /8# /5-# 21:1G'/34-PB@0# L-02-"/# 89# BP<*s# MN3;10-# AO<# J5-# PB@0iZ)@0–PS@0iZ)@0#3"4-0.-=3.82508"#';-#MJ3O#3.#$%%<Br $<Z#&'+5'43";# /5-# .':-#1"2-0/'3"/(# '.# /5-# LG'/-'1# ';-<#J5-3"3/3'G# Z)@0iPS@0# ';-# 3.# %WZr%%#&'# M&EK[Y# )<SZOMN3;10-#AO<#J5-#@0=@0#LG'/-'1#';-#89#$%$<W#&'#0-L0-=.-"/.#/5-#';-#89#X38/3/-#288G3";#,8C"#/8#/5-#2G8.-#/-:=L-0'/10-#MTPW)c>O#89#/5-#3.8/8L-<#

J5-#/8/'G#';-#89#$%#/-:L-0'/10-#./';-.#3.#$%%<*#&'980#/5-#.':LG-#H&]=$Z=P#MN3;10-#AO<#E-4-0'G#G8C#/-:=L-0'/10-# ./';-.# X-/C--"# W))c># '",# A))c># 0-.1G/# 3":125# 53;5-0# 'LL'0-"/# ';-.+# C5325# :'(# 5'4-# X--"2'1.-,#X(#/5-#3"1-"2-#89#"12G-'0#0-283G#80#/5-#'G/-0='/38"#89#/5-#:3"-0'G#L'0/32G-#.109'2-.#'",#5'4-#"8#;-8=G8;32'G# .3;"3932'"2-<# E3`# 53;5# /-:L-0'/10-# ./';-.X-/C--"# $+)))c># '",# $+Z))c># ,3.LG'(# '# 4-0(# '/LG'/-'1#C3/5#'"#';-#MJLO#89#$%)<Ar$<$#&'+#C5325#280=0-.L8",.# /8# /5-# 21:1G'/34-# PB@0# L-02-"/# 89# *$s#MN3;10-# AO<# @2280,3";G(+# /5-# PB@0iZ)@0–PS@0iZ)@03"4-0.-=3.82508"#';-#MJ3O#3.#$%$<$r$<P#&'+#L8..-..3";/5-#.':-#1"2-0/'3"/3-.#'.# /5-#LG'/-'1#';-<#J5-# 3"3/3'GZ)@0#iPS@0#3.#%*A<)rB<%#&'#M&EK[Y)<WSO#MN3;10-#AO+C5325#5'.# /5-# .':-#-0080# 0'";-# '.# /5-#@0# 0'/38#89#:8,-0"# '/:8.=L5-0-<#J5-#LG'/-'1#';-#89#$%)<A#&'#0-L0-.-"/.#/5-#4'G1-#C5-"#/5-X38/3/-#288G-,#,8C"#/8#/5-#2G8.-#/-:L-0'/10-#MTPW)cO#89#/5-#3.8/8L-<

J5-#@0=@0#LG'/-'1#';-.#89#X38/3/-#908:#.':LG-.#H&]=$Z=%#'",H&]=$Z=P#'0-#28".3./-"/#C3/53"#/5-#:-'.10-:-"/#1"2-0/'3"/(+#'",

2800-.L8",#/8#/5-#';-.#89#/5-#:(G8"3/-.#M$%)–$%%#&'O#C5-"#288G3";,8C"#/8#TPW)c><#J5-.-#';-.#0-L0-.-"/#/5-#/3:-#89#/5-#980:'/38"#89/5-#,12/3G-#,-/'25:-"/#'/#/5-#C-./-0"#:'0;3"#89#/5-#H8";:-"#E5'"28:LG-`<

Episodes, Vol. 31, No. 3

297

Table 1 Results of 40Ar/39Ar dating for the biotite from mylonite sample.

Figure 7 40Ar/39Ar age spectra and isochron of the biotite from mylonite samples of the Gezong complex.

Coseismic ruptures of the Wenchuanearthquake E-3.:32#C'4-980:#'"'G(.-.# MJ'XG-#%O#.58C#/5'/# /5-#$%#&'(#%))*&.Y*<)#:'3".5827#./'0/-,#908:#'#5(L82-"/-0#8"#'#"80/5C-./=,3LL3";9'1G/# M'a3:1/5# %P*+# ,3L# WBO# '",# L08L';'/-,# 1"3G'/-0'GG(# /8# /5-"80/5-'./#84-0#'#,3./'"2-#89#T%AW#7:#'G8";#/5-#H8";:-"#E5'"#0'";-908:#[1V3'";('"#/8#F1'";(1'"#MN3;10-#*O<#J50--#L03"23L'G#./0-..-.'0-#,-/-0:3"-,_#!1 MP)%+#)SO+#!2 M)PS+#P$O+# '",#!3 M%)%+#WAO<#J5--'0/561'7-+# C58.-# /0-:80.# G'./-,# 980# 'X81/# %#:3"1/-.+# C'.# 28:=L8.-,#89#/C8#.1X=-4-"/.#89#S–B#:#.G3L#MI'0.8".#-/#'G<+#%))*O_#/5-#-L3=2-"/0'G#.1X=-4-"/#1",-0C-"/#8XG361-#03;5/=G'/-0'G#/501./#.G3L+#C5-0-'./5-#"80/5-'./#.1X=-4-"/#.G3LL-,#G'0;-G(#03;5/=G'/-0'GG(<

!10#-G,#8X.-04'/38".#89#9'1G/#81/208L.#MN3;10-#BO#.58C-,#/5'/#':'3"# 28.-3.:32# 01L/10-# ,-4-G8L-,# 'G8";# /5-# b3";`31=U-3251'"=g3";251'"#9'1G/#84-0#'#G-";/5#89#T%AW#7:#'",#'#,-L/5#89#$W–%)#7:+'",#'#.-28",'0(#01L/10-#84-0#'#G-";/5#89#T$))#7:#980:-,#'G8";#/5-.81/5-0"#.-;:-"/#89#/5-#@"`3'"=F1'"`3'"##9'1G/#MN3;10-#*O<#J5-#G'//-0

3.#0-9-00-,#'.#/5-#908"/#9'1G/#89#/5-#H8";:-"#E5'"#0'";-<#N10/5-0:80-+/C8#:3"80# .109'2-# X0-'7.# 82210# X-/C--"# /5-# /C8# L03"23L'G# 01L/10-.:-"/38"-,#'X84-_#8"-#3.#T%)#7:#G8";+#'",#/5-#8/5-0#3.#'X81/#S#7:#G8";<J5-.-#:3"80#9'1G/.#'0-#-61'GG(#25'0'2/-03a-,#X(#EK=/8=R?#/501./3";/8;-/5-0#C3/5#03;5/=G'/-0'G#.G3L<#N08:#C-./#/8#-'./+#/5-#R?=/0-",3";#01L=/10-.#,3L#908:#"-'0G(#4-0/32'G#/8#W)Q–S)Q /8#/5-#"80/5C-./#MJ'XG-#PO+#'",/5-#':81"/.#89#"-/#.G3L# M3<-<+#,3.LG'2-:-"/O#'G.8#,-20-'.-.#;0',1'GG(<K-#8X.-04-,#/5'/#/5-#0-G'/34-#,3.LG'2-:-"/#89#-'25#28.-3.:32#.109'2-01L/10-#X-/C--"#/5-#5'";3";#C'GG#'",#988/C'GG#XG827.#4'03-.#28".3,-0='XG(#C3/5# /5-#./037-# MN3;10-#BO<#J5-#:'`3:'G#4-0/32'G#'",#5803a8"/'G28:L8"-"/.#89#/5-#.G3L#4-2/80#C5325#3.#L'0'GG-G#/8#/5-#.G327-".3,-.#MN3;=10-#BO#'0-#*<)#:#'",#$)<)#:+#0-.L-2/34-G(<#@#R?=./0373";#.'",#G361-9'2=/38"#a8"-#C'.#8X.-04-,#'G8";#/5-#.109'2-#/0'2-#89#/5-#@"`3'"=F1'"`3'"9'1G/#908:#l1(1'"#/8C"#89#[1V3'";('"#/8#l3'";(81#23/(+#3",32'/3";#/5-28.-3.:32#'2/34'/38"#89#/5-#,--L#XG3",#9'1G/#/5'/#C'.#3:';-,#X(#L0-43=81.#.-3.:32#L08G-.<#@"'G(.-.#89#/5-#^RE@f#3:';-.#'G.8#0-4-'G#2-0/'3"0-'2/34'/38"# 89# /5-#K-"251'"=&'8`3'"# 9'1G/+# 'G/581;5# "8# 2G-'0# 28=.-3.:32#01L/10-.#5'4-#X--"#981",#8"#/5-#.109'2-#X-/C--"#K-"251'"'",#&'8`3'"<#E-4-0'G#G'0;-#'9/-0.5827.#C-0-#0-G'/-,#/8#/5-#0-'2/34'/38"89#/5-#K-"251'"=&'8`3'"#9'1G/#MN3;10-#*O<

September 2008

298

Figure 8 Focal mechanism solutions and coseismic surface ruptures (red lines) of the Wenchuan earthquarke sequence.

bUgN_#b3";`31=U-3251'"=g3";251'"#9'1G/d#F@N_#F1'"`3'"=@"`3'"#9'1G/d#K&N_#K-"251'"=&'8`3'"#9'1G/d#HgEN_#H8";61'"#E5'"#9'1G/d#IgN_#I3";C1=g3";251'"#9'1G/d#&N_#&3"V3'";#9'1G/<

Table 2 Focal mechanisms of the mainshock and some aftershocks of the Wenchuan earthquake sequence.

J5-#-`/-".34-#.-61-"2-#89#/5-#'9/-0.5827.#3.#./08";G(#L8G'03a-,3"# /5-# R?# ,30-2/38"# X-/C--"# b3";`31# /8C"# '",# F1'";(1'"+# '",-`/0-:-G(#'.(::-/032'G#C3/5# 0-.L-2/# /8# /5-#-L32-"/-0#89# /5-#:'3"=.5827<# J5-# .L'/3'G# ,3./03X1/38"# 89# /5-# .1X.-61-"/# '9/-0.5827.# 3.1"':X3;181.G(# 28"/08GG-,# X(# /5-# 9'1G/.# :-"/38"-,# 'X84-<# E/0-../0'".9-0# X-/C--"# /5-# 9'1G/.# M-<;<+# E/-3"# -/# 'G<+# $BBZO# 3.# X-G3-4-,# /85'4-#-`-0/-,#'#28"/08G#8"# /5-#'9/-0.5827# /03;;-03";#'208..#'#X08',.L-2/01:#89#.L'/3'G#'",#/-:L80'G#.2'G-.#3"#/5-#H8";:-"#E5'"#0'";-<^/# 3.# C80/5# :-"/38"3";# /5'/# /5-# X13G,3";.# '",# 8/5-0# 28"./012/38".C-0-#:125#.-0381.G(#,':';-,#8"#/5-#5'";3";#C'GG#XG827#/5'"#8"#/5-

988/C'GG#XG827#'208..#/5-.-#28.-3.:32#01L/10-.#M-<;<+#b3";`31#/8C"'",#/5-#U-3251'"#>81"/(#/8C"O<

Fault-valve action

@.# :-"/38"-,# X-980-+# /5-# $%# &'(# %))*# K-"251'"# -'0/561'7-3"48G4-,#2G8.-=/8=L10-#0-4-0.-#.G3L#8"#/5-#L03"23L'G#G3./032#9'1G/.#,3L=L3";#./--LG(#MpS)–*)Q+#J'XG-#%#'",#N3;10-#BO#/8#/5-#"80/5C-./#3"#/5-$)–$W#7:# /5327# 1LL-0:8./# 201./<#J5-# .-61-"/3'G# '2/34'/38"# 89# /5-53;5='";G-#0-4-0.-#9'1G/.#3"#/5-#H8";:-"#E5'"#980:-,#'#25'0'2/-03.=/32# :'0;3"# X-/C--"# /5-# E8";L'"=F'"a3# /-00'"-# '",# /5-# E3251'"U'.3"+#C5325#5'.#/5-#./--L-./#/8L8;0'L532#;0',3-"/#89#'"(#-,;-#89#/5-:8,-0"# LG'/-'1.<# J5-.-# 01L/10-# LG'"-.# ,3L#:125# ./--LG(# /5'"# /5-:8./#9'480-,#,3L#'";G-#M#O# 980#0-4-0.-=9'1G/#-'0/561'7-.#M# = %S<S980#:8./#0827.#C3/5#'#9032/38"'G#28-99323-"/#µ = 0.AWO<#'..1:3";#580=3a8"/'G#:'`3:1:#28:L0-..34-#./0-..#M@",-0.8"t.#:8,-GO<#J5-#:3"3=:1:#0'/38#89# /5-#-99-2/34-#./0-..-.# M!1

$/!3$O+#C5325# 3.# 0-6130-,# /8

0-'2/34'/-#'#0-4-0.-#9'1G/+#3.#;84-0"-,#X(#/5-#9032/38"'G#9'3G10-#203/-=038"# 0-G'/-,# /8# /5-# .8=2'GG-,# 9'1G/=4'G4-# X-5'4380# ME3X.8"# -/# 'G<+$B**O_

(!1$/!3

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^"#/53.#-61'/38"+#!1$= !1 – Pf+#'",#!3

$= !3 – Pf+#C5-0-#!1 '",#!3 '0-/5-#:'`3:1:#'",#:3"3:1:#L03"23L'G#./0-..-.+#0-.L-2/34-G(d#'",#Pf3.# /5-# L80-=13,# L0-..10-<# J5-# 0'/38# 89#!1

$/!3$ 5'.# /5-#:3"3:1:

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Episodes, Vol. 31, No. 3

299

Figure 9 Typical coseismicsurface ruptures produced by theWenchuan earthquake.

M@–UO# @# R?=./0373";+# T# Z<P# :# 53;50-4-0.-# 9'1G/# .2'0L# 'G8";# /5-b3";`31=U-3251'"# 01L/10-# a8"-# '/U'V3'8:3'8# u3GG';-# C5-0-# 9'1G/LG'"-# ,3L.# A%–*)# RK+# C3/50-:'07'XG- .G327-".3,-.<##f-4-0.-+8XG361-#/501./3";<#

M>O#@#R?=./0373";+#T%<W#:#53;5#-`=10'G# .2'0L#89# '#X'27=/501./# 'G8";/5-# b3";`31=U-3251'"# 01L/10-a8"-#'/#F'8(1'"#u3GG';-<#

M[O#@#R?=./0373";+#%<%#:#53;5#-`10'G.2'0L#'G8";#/5-#F1'"`3'"=@"`3'"01L/10-#a8"-+#C5325#C-"/#/5081;5X-/C--"# /C8# X13G,3";.# 3"# /5-U'3G1#E2588G<#

M?O#@#R?=./0373";+#%<%#:#53;5#-`10'G.2'0L#'G8";#/5-#F1'"`3'"=@"`3'"01L/10-# a8"-# 21//3";# /5-# 88,=LG'3"#'",#X8//8:#89#H'8V3-#f34-0<#

MNO#@#R?=./0373";#-`10'G#.2'0L#V83"./5-#b3";`31=U-3251'"#'",#F1'"=`3'"=@"`3'"# 01L/10-# a8"-.<# J5-5803a8"/'G# '",# 4-0/32'G# 28:L8="-"/.#89#/5-#28.-3.:32#.G3L#'0-#%<A:#'",#$<P#:+#0-.L-2/34-G(<

Table 3 Orientations of coseismic ruptures and slickensides.

L3";#:80-#/5'"#ZWQ '0-#1"9'480'XG(#803-"/-,#980#0-4-0.-#.G3L#M-'0/5=61'7-O#3"#/5-#./0-..#-G,<#^"#80,-0#/8#'2/34'/-#80#0-'2/34'/-#'#0-4-0.-9'1G/#C3/5## > WP<%Q M/5-#:8./# G37-G(#2'.-# 980# /5-#28.-3.:32# 9'1G/.C3/53"# /5-# 1LL-0:8./# 201./# 89# /5-# H8";:-"# E5'"# 0'";-O+#!1

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New interpretation of GPS data

FIE+#'#/-25"361-#/8#:-'.10-#/5-#0-G'/34-#5803a8"/'G#:8/38"#4-G823/(X-/C--"#/-2/8"32#XG827.+#5'.#X--"#-`/-".34-G(#'LLG3-,#/8#/5-#J3X-/'"LG'/-'1#'",#3/.#.10081",3";#0-;38".#M>5-"#-/#'G<+#%)))d#k5'";#-/#'G<+%))ZO<#J5-#FIE#4-G823/3-.#X-/C--"#/5-#^",3'"#'",#?10'.3'"#LG'/-.4'0(#908:#%*<)#::i(0#/8#PZ#::i(0+#3"20-'.3";#;0',1'GG(#908:#2-"=/0'G# h3:'G'('# /8# /5-# -'./-0"# h3:'G'('"# E("/'`3.# Mk5'";# -/# 'G<+%))ZO<#K3/53"#/5-#J3X-/'"#LG'/-'1+#/5-#H5'.'#'",#g3'";/'";#XG827.C-./# 89# BWQ G8";3/1,-# :84-# /8# RP)Q–ZAQ?# '/# /5-# 0'/-# 89#%A–P)#::i(0#MN3;10-#%O<#J5-#-'./-0"#L80/38"#89#/5-#g3'";/'";#/-0=0'"-+#G82'/-,#.81/5#89#/5-#G-9/=G'/-0'G#]3'".5135-#9'1G/+#:84-.#.81/5=-'./# 0-G'/34-# /8# /5-# E3251'"#U'.3"# '/# '# 0'/-# 89# %*# rW#::i(0<# J5-g'3,':#U'.3"#'",#/5-#E8";L'"=F'"a3#/-00'"-#"80/5#89#/5-#e1"G1"9'1G/#:84-#/8#RS)Q?#'/#0'/-.#89#$%–$Z#::i(0<#h8C-4-0+#/5-#28"4-0=;-"2-#'208..#/5-#H8";:-"#E5'"#0'";-#3.#.G8C_#j%#::i(0#'208..#/5-&3"#E5'"+#T$#::i(0#'208..#/5-#"80/5-'./-0"#.-;:-"/#908:#@"`3'"/8# g3";251'"+# '",# j$<W# ::i(0# '208..# /5-# .81/5C-./-0"# .-;:-"/

908:#H1,3";# /8#U'8`3";# '",# /5-# 2-"/0'G# .-;:-"/# 908:#U'8`3"# /8&'8`3'"<#f3;5/=G'/-0'G#.G3L#89#T$#::i(0#82210.#'G8";#/5-#"80/5-'./=-0"#.-;:-"/#89#/5-#H8";:-"#E5'"<#FIE#,'/'#C-0-#:3.3"/-0L0-/-,#'.'"# -43,-"2-# 980# 3"'2/343/(# 89# /5-# H8";:-"# E5'"# 9'1G/.# '",# /51.3:L8..3X3G3/(#89#./08";#-'0/561'7-.#3"#/5-#0-;38"#M>5-"#-/#'G<+#%)))dk5'";#-/#'G<+#%))%+#%))Zd#[-";#-/#'G<+#%))SO<#J5-.-#'1/580.#2G'3:-,/5'/#G3//G-#:84-:-"/.#/'7-#LG'2-#'G8";#/5-#H8";:-"#E5'"#9'1G/.#,1-/8# /5-# 51;-# ':81"/# 89# 201./'G# :'/-03'G# .81/5# 89# /5-# ]3'".5135-=@""3";5-=]3'"V3'";#.3"3./0'G#./037-=.G3L#9'1G/#a8"-#:843";#.81/5-'./908:#.81/5-'./-0"#J3X-/# '",#"80/5C-./-0"#b1""'"# /8# .81/5-'./-0"b1""'"+#'",#/8#'"#3:L80/'"/#2G827C3.-#08/'/38"#'081",#/5-#-'./-0"h3:'G'('"#E("/'`3.#Mk5'";#-/#'G<+#%))ZO<

^/# 3.# 3:L80/'"/# /8#"8/-# /5'/#Z#-'0/561'7-.#C3/5#&. *<)#'",#$)-4-"/.#C3/5#&.YA<)–A<B#C-0-#G82'/-,#3"#/5-#0-;38".#C5-0-#/5-#FIE4-G823/3-.#'0-#:'07-,G(#G8C#80#C5-0-#/5-#5803a8"/'G#:8/38"#0',32'GG(25'";-.#,30-2/38"<#J5-#G8C#FIE#4-G823/3-.#'0-#981",#.(./-:'/32'GG('/# /5-#908"/.#89# /5-#-"G'0;3";#J3X-/'"#LG'/-'1#';'3"./#05-8G8;32'GG(./08";#XG827.#.125#'.#/5-#E3251'"#U'.3"+#@G'#E5'"#'",#!0,8.#XG827.<^/#3.#4-0(#G37-G(#/5'/#/5-.-#908"/#a8"-.#'0-#25'0'2/-03a-,#X(#/5-#,-4-G=8L:-"/#89#./--L=/8=4-0/32'G#2G8.-=/8=L10-#0-4-0.-#80#0-4-0.-#8XG361-.G3L#9'1G/.#'208..#C5325#/5-#FIE#/-25"361-#5'0,G(#,-/-2/.#/5-#5803=a8"/'G#28"4-0;-"2-#0'/-.#,103";#'"#3"/-0.-3.:32#L-038,<#^"#/5-#9'1G/a8"-.# ';'3"./# 05-8G8;32'GG(# ./08";# XG827.+# ,399-0-"/3'G# ./0-..# 2'"'221:1G'/-#/8#.125#'#53;5#G-4-G#/5'/#/5-#&.!A<)#-'0/561'7-#01L/10=3";#2'"#0-.1G/<

Conclusions

M$O# J5-# $%# &'(# %))*# K-"251'"# -'0/561'7-# M&.Y*<)O# 822100-,C3/53"#/5-#28"/-`/#89#G8";=/-0:#1LG39/#89#/5-#H8";:-"#E5'"#0'";-'.#'#0-.1G/#89#/5-#-'./C'0,#-`/01.38"#89#/5-#201./'G#:'/-03'G.#908:/5-#J3X-/'"#LG'/-'1#';'3"./#/5-#05-8G8;32'GG(#./08";#201./#89#/5-E3251'"#U'.3"<#J5-#0'";-#3.#25'0'2/-03a-,#X(#'#I0-=E3"3'"#20(.=/'GG3"-# 28:LG-`# 28"./0'3"-,# X(# /5-# &'8`3'"=K-"251'"=e'";,3";# ,12/3G-# ,-/'25:-"/# '/# /5-# C-./-0"# :'0;3"# '",# /5-b3";`31=U-3251'"=H1,3";# ,12/3G-# /501./# '/# /5-# -'./-0"#:'0;3"<J5-#1LG39/#89#H8";:-"#E5'"#C'.#3"3/3'/-,#X(#/5-#3"/0'28"/3"-"/'G.1X,12/38"#X-/C--"#/5-#E8";L'"=F'"a3#/-00'"-#'",#/5-#b'";/a-XG827#,103";#/5-#I0-=>-"8a832<#J5-#1LG39/#0'/-#C'.#3"20-'.-,#28"=.3,-0'XG(#X(#/5-#28GG3.38"#X-/C--"#/5-#^",3'"#'",#?10'.3'"#LG'/-..3"2-#TW)#&'<

M%O#J5-#K-"251'"#-'0/561'7-#./'0/-,#8"#/5-#"80/5C-./=,3LL3";#9'1G/M%P*+#WBO+#7"8C"#'.#/5-#b3";`31=U-3251'"=g3";251'"#9'1G/#'",L08L';'/-,# 1"3G'/-0'GG(# /8# /5-# "80/5-'./# 84-0# '# ,3./'"2-# 89#T%AW#7:<#J5-#:'`3:'G#4-0/32'G#'",#5803a8"/'G#28:L8"-"/.#89#/5-28=.-3.:32#.G3L#'0-#*<)#:#'",#$)<)#:+#0-.L-2/34-G(<#N08:#EK#/8R?# 'G8";# /5-# 9'1G/+# /5-# /501./# 28:L8"-"/# ,-20-'.-.# ;0',1'GG(C53G-# /5-# ,-`/0'G# ./037-=.G3L# 28:L8"-"/# 3"20-'.-.<# J5-# /0-:80:84-,#-'./# /8# /5-#F1'"`3'"=@"`3'"#9'1G/+# 980:3";#'#28.-3.:32.109'2-#01L/10-#89#T$))#7:#G8";<#J53.#.1;;-./.#/5'/#/5-#&.Y*<)-'0/561'7-# 908:# /5-# b3";`31=U-3251'"=g3";251'"# 9'1G/# /03;=;-0-,#/5-#-'0/561'7-.#8"#/5-#F1'"`3'"=@"`3'"#9'1G/<

MPO# J5-# K-"251'"# -'0/561'7-# 3"48G4-,# 2G8.-=/8=L10-# 0-4-0.-# 8003;5/=0-4-0.-#8XG361-#.G3L#8"#./--LG(#,3LL3";#9'1G/#LG'"-.#C5325C-0-# 1"9'480'XG(# 803-"/-,# 980# '2/34'/38"i0-'2/34'/38"# '",'LL08'25-,#9032/38"'G#G827=1L#3"#/5-#0-;38"'G#5803a8"/'G#28:L0-.=.38"'G# 0-;3:-<#J5-#822100-"2-#89#28.-3.:32# .G3L#8"# /5-# ./--LG(,3LL3";#9'1G/.#3:LG3-.#.8:-#28:X3"'/38"#89#-`/0-:-G(#53;5#G-4-G.89#X8/5#0-;38"'G#/-2/8"32#'",#13,#84-0L0-..10-<#

MZO#^"#"80/5-'./-0"#J3X-/'"#LG'/-'1#'",#3/.#.10081",3";#0-;38".+#G'0;--'0/561'7-.# C3/5# &.!A<)# 822100-,# 3"# /5-# 9'1G/# a8"-.# '208..C5325#/5-#FIE#4-G823/3-.#'0-#:'07-,G(#G8C#MjP#::i(0O<#J5-#G8CFIE#4-G823/(#a8"-.#'0-#3",--,#/5-#908"/.#89#/5-#-"G'0;3";#J3X-/'"LG'/-'1#';'3"./#/5-#05-8G8;32'GG(#./08";#XG827.#M3<-<+#/5-#E3251'"U'.3"+#@G'#E5'"#'",#!0,8.#XG827.O<#J5-#9'1G/.#'0-#./--LG(#,3L=L3";# 2G8.-=/8=L10-# 0-4-0.-# 9'1G/.+# 'GG8C3";# /-2/8"32# ./0-..# '",13,#L0-..10-# /8# '221:1G'/-# /8# '# 203/32'GG(#53;5# G-4-G# 980# G'0;--'0/561'7-#"12G-'/38"#'",#L08L';'/38"<

September 2008

300

Acknowledgments

J53.#L08V-2/#C'.#.1LL80/-,#X(#/5-#>53"'#F-8G8;32'G#E104-(#'",#/5-RE?f>#89#>'"','<#g3'"#K'";#'",#E5-";.3#E1"#'0-#/5'"7-,#980#,3.=21..38"d#&3'8#k5'";+#>13L3";#]1#'",#b4-032#f81..-'1#980#,0'C3";/5-#;10-.d#'",#I089<#l'261-.#&'0/3;"8G-#980#28"./012/34-#0-43-C#89/5-#:'"1.203L/.<#

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U1025-G+#U<><+#f8(,-"+#H<h<+#4'"#,-0#h3G./+#f<[<+#h';-0+#U<h<+#>5-"+#k<+e3";+#f<K<+#H3+#><+#H1+#l<+#b'8+#h<+#'",#e30X(+#?<+#%))*+#@#;-8G8;32'G#'",;-8L5(.32'G# 28"/-`/# 980# /5-# K-"251'"# -'0/561'7-# 89# $%# &'(# %))*+E3251'"+#>53"'_#FE@#J8,'(+#4<$*+#"8<#A+#,83_#$)<$$P)iFE@JF$*@<$<

>5-"+# E<N<# '",#K3G.8"+# ><l<H+# $BBW+# ?:LG'2-:-"/# 89# /5-# H8";:-"# E5'"/501./="'LL-#X-G/#'G8";#/5-#-'./-0"#:'0;3"#89#/5-#J3X-/'"#IG'/-'1_#l810"'G89#E/012/10'G#F-8G8;(+#4<#$*+#LL<#Z$P–ZP)<

>5-"+#k<H<+#U1025-G+#U<><+#H31+#b<+#e3";+#f<K<+#f8(,-"+#H<h<+#J'";+#K<+K'";+#?<+#k5'8+#l<+#'",#k5'";+#]<+#%)))+#FG8X'G#L8.3/38"3";#.(./-:#:-'=.10-:-"/.# 908:# -'./-0"# J3X-/# '",# /5-30# 3:LG32'/38".# 980# ^",3'i?10'.3'3"/-028"/3"-"/'G#,-980:'/38"_#l810"'G#89#F-8L5(.32'G#f-.-'025+#4<#$)W+LL<#$S%$W–$S%%A<

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F0'/3-0+#l<I<+#N'40-'1+#I<+#'",#f-"'0,+#N<+#%))P+#&8,-G3";#13,#/0'".9-0#'G8";>'G3980"3'# 9'1G/.# C5-"# 3"/-;0'/3";# L0-..10-# .8G1/38"# 20'27# .-'G3";# '",28:L'2/38"# L082-..-._# l<# F-8L5(.<# f-.<+# $)*+# U%+# %$)Z+# ,83_$)<$)%Bi%))$lU)))P*)<

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Episodes, Vol. 31, No. 3

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Zhiqin Xu is Research Professor atInstitute of Geology, Chinese Acad-emy of Geological Sciences, andmember of Chinese Academy of Sci-ences. She obtained her PhD fromUniversity of Montpellier, France in1986. Her current research interestscover the deformation process andmechanism for rocks from variouslevels of continental lithosphere andtectonics of major orogenic belts.She has been playing a leading rolein Chinese Continental ScientificDrilling (CCSD) project on the Suluhigh- to ultrahigh- pressure (HP/UHP) metamorphic belt and, formore than ten years, in the Sino-French collaboration projects forstudying the Tibetan plateau and itsmarginal orogenic belts.

Shaocheng Ji is professor of EarthSciences in the Department of Civil,Geological and Mining Engineering,Ecole Polytechnique de Montreal(Canada), obtained his B.Sc. fromNanjing University (China), andPh.D. from the Université deMontpellier II (France). He hasbeen involved in research andteaching in petrophysics, structuralgeology and geophysics for over 20years. He is author of 3 books andover 80 research papers.

Haibing Li is Research Professor atthe Institute of Geology, ChineseAcademy of Geological Sciences,and is Director of the ContinentalDynamics Laboratory under theInstitute. He obtained his Ph.D. in2000 from the CAGS. His scientificinterests are focused on tectonicgeomorphology and active tectonics,mountain building and neotectonicstructures.