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Page 1: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

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High-Resolution P-wave Seismic Reflection Imaging of

the Yoro Active Thrust: ,**. Shizu Profile

Tatsuya Ishiyama+�*, Hiroshi Sato,�, Shigeru Toda-�, Toshimichi Nakanishi.�, Nobuhisa

Matsuta/�, Nobuhiko Sugito0�, Hiroyuki Tsutsumi1�, Atsumasa Okada2�, Taro Koike3�,

Tomohiro Imamura+*�, Yasuhisa Hattori++�, Norimasa Suzuki+,�, Keigo Amano+-�, Yoshito

Kato+.�, Yohei Kawai+/� and Keiji Takaki+0�

+�Active Fault Research Center, National Institute of Advanced Industrial Science and Technology

(Present Address : Graduate School of Science, Tohoku University), ,�Earthquake Research Insti-

tute, the University of Tokyo, -�Aichi University of Education, .� Institute of Geology and Geoinfor-

mation, National Institute of Advanced Industrial Science and Technology (Present Address : Public

Works Research Institute), /�Earthquake Research Institute, the University of Tokyo (Present

Address : National Taiwan University), 0�Graduate School of Science, Kyoto University (Present

Address : Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of

Environmental Studies, Nagoya University), 1�Graduate School of Science, Kyoto University, 2�

Graduate School of Science, Kyoto University (Present Address : Research Center for Disaster

Mitigation of Urban Cultural Heritage, Ritsumeikan University), 3�Geosys, Inc., +*�Graduate School

of Science, Kyoto University (Present Address : Tango Civil Engineering O$ce, Kyoto Prefecture), ++�

Graduate School of Science, Kyoto University (Present Address : Japan Energy Co., Ltd.), +,�Aichi

University of Education (Present Address : Toyota Municipal Wakazono Junior High School), +-�

Aichi University of Education (Present Address : Mitsubishi Electric Co., Ltd.), +.�Aichi University of

Education (Present Address : Nishio Municipal Nishio Junior High School), +/�Aichi University of

Education (Present Address : Toyota Auto Body Co., Ltd.), +0�Aichi University of Education (Present

Address : Sanaru Co., Ltd.)

Abstract

We present new, high-resolution seismic reflection data (,**. Shizu profile) acquired across the

forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic

source (mini-vibrator) and +2*-channel digital telemetry recording system were used in an o#-end

configuration with the nearest receiver adjacent to the source to record seismic waves from deeper

* e-mail : [email protected] K�32*�2/12 �dw����� �� 0�-�

V W A B C ¡ ^Bull. Earthq. Res. Inst.

Univ. TokyoVol. 2, K,**1� pp. 0/�1.

¢ 65 ¢

Page 2: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

reflection points. A +*-m source and geophone spacing give a /-m CMP (common midpoint) spacing

on the final section. The nominal CMP stacking fold had 3* traces. We also suppressed coherent

noise by repeating source points 1�+* times. After data processing including surface-consistent

statics, velocity analysis, normal moveout (NMO) correction, residual statics, CMP stack, and mi-

gration, the section was finally depth-converted using of stacking velocities. Reflectors imaged on

the seismic profile illuminate growth strata on the forelimb of the Yoro basement-involved fold,

providing insights into the kinematic solution of the underlying active thrust.

Key words : active fault, Yoro fault, seismic reflection profile, subsurface structure, central Japan

+� ���������� ��������������� �� ��������������� ������� ���� ++* km� ��������������� ����� !� +33+ ; ��"#� +330 ; ��"#�,**, ; ���$ � ,**, ; Fig. +�%����&'��!�(�"��)*+�#,-�� $%� �.�,***�� /01� +/20&'(�) �23*� ,**+� �4�+*0567810� �,9"#� +333 ; .� ,*** ;

-:"#� ,**,�% �5 '�� ������.��6����;/<=>��)?�+��7@��!�01�;/���% ����<���� ,9�2: �+332�<=A3B �+333� P4)C�567�)8D�9E�� ��:��;+���F�G ��:;�<=��>��H�"?!���I@�;/�A�/6+J����% �#�� /01�8DBC��� (�D�#,-��K��EL��FGH�IMH J /**

mKLN5OBC�P���<O� /�QR��0SM TN����% >�UV� +/20&'(�)?�#,-6OWXY�P�� QZ���;/�[\]^�RA���_'����%>/�������>��H�"�QZ���;/�[\]^`a�S5�T@6��� bH�$)�UV��� cWd6ef10�BC �,**.&gIBC� �XY�� hijjkliZ!567�)8Dmnop�[\�5 P4]�567�)8D�9E�5% ^q��� BC)_�rBst\]u�S6��8D�v16� w`UVx��ay��% �<� ^8DOA105�bKXz������L;/{���|}@wc� Ishiyama et al.

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vR��'5% BC�� S�t ,/2�C6Btm�{��C�U�ht!)_��% �w���v���e�x�6wy�zt{�[`u]j�`^�U��t,/2�C�� v����| }�% /01���~��Bt�Y��zhtE���5f� BC!����[��� i�¡���z��% �5� BC!�¢£��EX�e�zx#�¤Y�[�C¥��% >/��¦��dOht��t§�t�[\�� �[�C#1�¨��6���5% Btm�{��C�P���QR��� BC�gInobH��X�5% '©�rB�R����vª�'��O� «¬�bH�E���[� cWd��­L�rB��'5% 5®�� ��:;<Y�rB?�:�#1�¯L°�����[� �±�±$��5%

,�, �� !"��^8D�S�²]uRAst\]u� Table +³

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Page 3: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

+2*� ��������� �� +* Hz���� 3��������� ���������� � !"#$%&'�#()� +* m*��� +,-� ./0�12 +.- km3(��� 45��678� -9!"#:#-$;<'��=>�� '�?@ABC� +/

sec, � �� +*�+,* HzDEFGB?@AB����

HI45��� JKL@MNOPQ�<RST;UDVW�XY�� Z[� +*\*��� �]�� UD^_-$;<�`aL@MbcT;� HI45�� 1\*��� defd45�� 3*���� g�� hijkKlm,� nop��qr8�:stubvw�xwy-zJ�<;�{*b|}+~� ����� +333 ; ���

Fig. +. (a) Shaded relief map based on ,/* m digital elevation model (DEM) (Kishimoto et al., ,***) showing the

topography and distribution of active faults within the Kinki region, central Japan. Locations of active faults

are from Nakata and Imaizumi (,**,). Red, orange, and gray lines mark active faults that are precisely located,

approximately located, and inferred, respectively. Barbs denote hangingwalls of active thrusts. Arrows in-

dicate slip directions of strike-slip faults. Abbreviations for metropolitan areas are : KB : Kobe, OK : Osaka, KT :

Kyoto, NG : Nagoya. (b) Regional Geologic Map of the Nobi-Ise fault zone including Yoro fault (modified from

Ishiyama et al., ,**1). Geologic units are modified from Miyamura et al. (+310), Takada et al. (+313), Yoshida

(+32. ; +322), Harayama et al. (+323), and Yoshida et al. (+33+). Red line with solid circles indicates location of the

seismic line in this study.

,**.�no����jk��������UD

� 67 �

Page 4: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

��� +332�� ������ ���������������������� �!"�� +2*#$%&�'()*+�,-./�01�234�56� 789:7;<=>2./� �?��@ABCCD B�� B�EFG0HIJK%&, +,2** m2L�� MNO�34O�PQ,&8R9ST8#$;�U6�V� W���XYB��Z[\�]^_`,abcd�e���G6��

Fig. -�34Ofg +*03 hi�1jk�� l ++20 hi��mi� n�ol ++-0 hi�?jk� �np�#$%&_`�q�� i�1jk�rstu2,vw�cd�E

xy]^z +./ sec{2ab�|}2(�� ~=� i�?jk2,xy]^z + sec{2�abE[cd��|}����E2(�� �����cd�, �0?��34_`2�}�[\�� {�� ����H(6i�1jk2,IJK%&�H(6��2���AE�ab��E� �\��2,�./�����ab���A��6����E2(��

-� ����� P���� ������������������*��2Z�]^_`�U6G� cdi������

Fig. ,. Detailed topographic map showing locations of survey line with receiver points and stack line with CMP

(common midpoint) numbers. Locations of active fold scarps along the Yoro fault is redrawn from Ikeda et al.(,**,).

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� 68 �

Page 5: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

������������ �� ���������������������� ProMAXTM �Land-

mark��� �� � �������!"#$%&'

��()*+ Yilmaz �+321� �,�-./"0����123������4��� 56�78������9 �:;/ 8<+ ����=�>?��� Fig.

.�+ @���7ABC��� Table ,�DE� FGC�H�IJKL�MN%� O%�P�Q�()*RS�FGC�H�T�/K!�+ U.�V��!"#$%���&'W�XY��Z[&'RS�IJ�� �Fig. ,� \�+ &'RS�() �!"#$%�P��]J�+ ^_`�3��a`b��c*de+ CMP�f����� ghiAj��kl�����8m�no�pqrsto��Bhbupqr��vE/���ghiAj��kl���L���L����w�+ Ox�jq�yo�W��z��+ {j��|}��~��]J�� \�+ RS���E/��S���E/����pqr���E;�+ 0* Hz

�p`>��kl���L���� �h�H��^_h��kl���R�� �(���� ��\./�R����s�o��&�����������}����+ ���8qhAlj�����E;�+ �h�H��^_h��kl���I��+ 3����L��� G� ���¡��R¢��£.¤.���¥¦§¨�©ª�+£�|}��~«�E/UK[¬�­®��T��� ��¯�°�� ±�n²³�����´J�+ £�12��E/µ¶���E/���+ ��¯�°�L��� CMP

Table +. Recording parameters for the ,**. Shizu

seismic reflection profile.

Fig. -. Shot gathers obtained at shot points +*03, ++20, and +-+0.

,**.!"#���·�����O¸¹�º»RS

¼ 69 ¼

Page 6: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

������������������ ������������� ����������� �!" �#$%�&��'(�)*+� ,�-.��/0� 1��2�3 45�67 8�9&#�:; +�,&<=�>? Fig. /

1a3 �� @A<B 1final datum3 �C/%2�-Fig. / 1b3 �D/6 �� * mEF�GHIJ��.K%L ���MN/%!" .O� ; +&<=�>?P+,*** m�secEFQ�R�ST6U��VWX�YZ�[\>?]�^U8� _8O`abP��c�de/%_QQfgh.K%6 U�� i�j5k��lmno/%<Wp����q?Prst%��Cu�k�; +�,

&<=�>?Ovw/%6 _��x�� m��y�m&���Q�����%�&2��z{O|}fgh.K%6 U�� 7 8�>?n~O_8U.� 8%���&�w�ht>?n~Qfgh.K% 1���� +333 ;

����l� +33236� >?��QNMO�>?������Q�>?�g�������g>?*+�6 >?��O� L �����h���tn~���.O CMP +** #��� ���&�����y#�:��c.O CMP,/ #��45�6 7 8�>?n~ Fig. 0�D/6 � �� 7 8����g>?�Tk���������� 1NMO3 �4T�  ¡¢£¤¥�� CMP�¦§¦����¨��6 NMO

��©�kO¢£¤¥��w�T����ª¥«¬­�����®¯/%QQ[�� NMOF�¬­��45�6>?���z{7 8�>?n~ Fig. 0�D/6 L ��.O�&2��°�F�[±² ³� ´���,** msecU. +,/** m�secµ¶Q�R�ST���g>?.K%P� _8O����l 1+3323 �>?��z{Qfgh.K%6 U�� �&VWX.O���g>?P -,*** m�secQ·¸�w�st%6 _8O� L ��

Fig. .. Flowchart of data processing.

Table ,. Processing parameters for the ,**.

Shizu seismic reflection profile.

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¼ 70 ¼

Page 7: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

������������ �� ��������������������� !"# $%&'�()*+�,-�./��01��23456�7� 89:;<=>:;<;<"?6@A# BACD�=>�&'./�EF��GH�I6�89�;<"# $%JK�L1�MN# 89:;<�OP"07� QR�ST$%NMO;<U# CMPVWXWYZ�[\]^�$%

"07 _�`a�bc# )d$%&'2e@�&'�fgChiWjklmn�opqrsN�tuv6# S�Nwq+!��7 x560$%yz{|� Fig. 1 }a~ ���7

� $%U`a$%U�`a2"�# �SN@��]\W�]�@AiWjklmn�tu"# ��C�����L1�MN����Z�]����� F-X��W���]��W�OP"07� �m�\]��W������|����������01�# F-k�m�\]��W�OP"07 �m�\]��W��K�Fig. 1 }b~ ���7$%yz{| }Fig. 1 }a~~ �w �#{>!�¡�������|�����¢£@¤0_2�¥¦�7�� §'.¨&'©ª��Kx560&'�«¦5¬S&'�­

Fig. /. (a) Near-surface velocity structure based on refraction statics calculation. Dark gray, light gray and

dashed lines indicate velocity of the bottoms of weathered and underlying two layers, respectively. (b) Receiver

(open squares) and source (solid circles) statics to final datum based on refraction statics calculation.

,**.®��{>�¯>��°�±²³�´µ�¶

· 71 ·

Page 8: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

�� ������������ ����� Fig. 2

���

.� ���������������� ������ , km���������� !�"�� #Fig. 2$ ��� ������%��&�' ()*�� ������+�',-�.-���/�0�1��'234������5�"�� ��� ��6�������789:;<"�=���>?� �� �@A��� -,*** m�sec

���B'�C! � �� D��6����>�'����%��+��B'CEF �' ��� ��6���� ()*��G�D� �HI��J�K�'CCL��M%�H�� N�' growth strata�!� �� ��O"�#P$J���&%��?��'#Ishiyama et al., ,**1$ &QRD +/20'(ST #UV)� ,**+$ W�K&X��CEF �'�JYK�Z�?��' [*��C+,�� ������JYK�\�D growth strata\��H4]�^-?��' ���CD� +/20'(STW�K&X������_`a[*����JYK�� �b�L ()*�c�"�defghih<�j.��K&X���C��?��' #Ishiyama et al., ,**. ; Ishiyama et al.,

,**1$

/� �,**.' 2k //! + +1/�!l�� m0n��1o2! +3�1 #p�/4q$ r456�s't%7

/.. km�QR�� �u8vTwx9��=:T;yzh{|�<�?����}��=:T;y�~�?� X �� �Q�9�����=>��=:�9�����<de��`��=����&?� �������6���>�'234������� ������+�',-�.-��1��'���5�"�� ��� ����%�?@�' growth strata����5�"��

� �Q��?�D� #�$g�zh�VA B����C���� ��� �Q�9���DtE����D�#�$g�zh��� F�_`a�G ��! ����H�� ��� &��IJDyK��B'���L����M�`�� X�� 3�1 #p�/4q$ N¡���1N¡_`am0n¢£��¢£¤�¥¦§G�D�¨�©OItE�¥?�t�P���CH�� X �� ��19�@% #QW$ �G S��Dª�C�'«¬R�S­D;yTP���®HI� Uy~��?,­"V¯�°��H�� ±��S­�=?�� ���²³�W� "_� &;y��?�D��& +0�+1 '�L�´µvw¶XY�· \�w¶#A$ ¸Z[¹ +0,***/* #w¶\W� : ºG]S$ �¨�?�

Fig. 0. Stacking RMS velocity structure based on velocity analysis.

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Page 9: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

Fig. 1. (a) Filtered stack section and (b) migrated time section based on data processing.

,**.����������� ������

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Page 10: High-Resolution P-wave Seismic Reflection Imaging of the ... · forelimb of the Yoro basement-involved fold to further image its subsurface geometry. A seismic source (mini-vibrator)

� ����� +333� �� ++�� ���������� http :

//www.hp+*-3.jishin.go.jp/kozo/Aichi0Cfrm.htm.

� ���� ��������������� +323����������� �������� / �� + ��!�"� ������ +./ p.

#�$��%&'���()���*+,���-��.���/�� ,**,� 0123456789� �:;�<�=�,/. p.

>�?���()��%&'��.���/�@� A�� �� B C ,**," : ��45�DEF45�G�H�H�IJKL �MNO!�P/NQR �STUVW��45��5"XYZ��K� [45��� ,,� ++/�+,0.

Ishiyama T., K. Mueller, M. Togo, A. Okada, K. Takemura,

,**., Geomorphology, kinematic history, and earth-

quake behavior of the active Kuwana wedge thrust

anticline, central Japan, J. Geophys. Res., +*3, B+,.*2,

doi : +*.+*,3/,**- JB**,/.1.

Ishiyama, T., K. Mueller, H. Sato, and M. Togo, ,**1, Coseis-

mic fault-related fold model, growth structure, and the

historic multisegment blind thrust earthquake on the

basement-involved Yoro thrust, central Japan, J. Geo-phys. Res., doi : +*.+*,3/,**0JB**.-11.

[45��=� +33+� \E� #�[45K�$!]^%_��:;�<�=� .-1 p.

`ab� ,***� M&cdefg#h'�ijkl�Hmno�p� : Japan,/*m.grd, �������^%q CD-

ROM"� -/-� + CD-ROM, �����r�� ������s�t�� +310� (u�)������

�������� / �� + ��!�"� ������ .3 p.

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.���/� +330� �:;��|���T*+}~g,�-�|��k9��� [45��� +/� +**�+*/.

��'(����+� +332� ;��,�-�|��T�W�����[��� �������� no. EQ�32�+ �� 3

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©.�B2� ,**-�#Cª�|«D : ¬.+0­�,**+� �:;�<�=� 0*/ p.

Yilmaz, O., +321, Seismic Data Processing, Soc. Exploration

Geophys., Tulsa, Oklahoma, /,0 p.

����� +32.� 1#������� �������� / �� + ��!�"� ������ 2+ p.

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Received March +/, ,**1" Accepted May 3, ,**1"

Fig. 2. Depth, migrated section based on data processing (Modified from Ishiyama et al., ,**1).

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