Upload
others
View
10
Download
0
Embed Size (px)
Citation preview
� � �
�
�
�
� � � � � �
� � � � �
�
� � � � � �
�
� � �� ��� �
�
�� � �
� �� �� � � ��
� �� �� �
�� � �� �
��
� �
� ������� � ��������� ������� ����
! "�#$��%�&'%�()*+,-./0123 4 567 8 9/ :;<=�� />?@ABCDEF? GHI2B"�#$ JK �&L �&'%M'E!MN%OLPB9Q# RSI2
P! TU%VUE W/X Y%Z[+\ ]^ _`I2 a%�Tbc!d'#ef? ghI2 �&' %�&LP%�ibcAjkJlm+\> @%�ib! M'+noA>?Ba%Ip 9% !d'q/9 cr+sL>? %tu+vw# xyz{|}~Q#ef? z����+��#$ ��E! ��#$����"�>?�d��+�t>?$�/! OLPJK%� %��AL�21����?�()*/�fe��()*BCDJ�/J? �()*21"�>?��% 3:;<=��%�&LPA%��/�fe�����LP%Z[JK%�t�Y+U`��?$�/ >?
GH��� S� ¡ ¢r £ ¤H¥¦ §�¨© ªH«�
� ����
���� ��������� ���
� � �
� �
� � � � �
265
JMA
JMA
Bull. Earthq. Res. Inst.
Univ. Tokyo
Vol. pp.
* e-mail : [email protected]
Earthquake Research Institute, the University of Tokyo
JGI Inc.
Graduate School of Science, Chiba University
The seismogenic source fault of the Noto Hanto earthquake (M . ) runs beneath the
northwestern part of the Noto peninsula and its o shore trending ENE-WSW. To reveal the rela-
tionship between a seismogenic source fault and geologic structure, shallow, high-resolution seismic
reflection and refraction profiling was undertaken across the source fault along the western coast of
the Noto peninsula for km distance. The seismic source was a vibroseis and seismic data were
recorded by fixed channels. The P-wave refraction analysis delineated the three layered velocity
structure down to km ; . km/s, . km/s and . km/s layers. The . km/s layer, which corre-
sponds to the lower Miocene fluvial sediments, shows northward thickening with steps. On the
resultant depth converted seismic section, south and north-dipping, faults are interpreted based on
the systematic change on dip-angle of the reflectors in the lower Miocene fluvial sediments. By
comparing with the aftershock distribution, the deeper extension of the south-dipping fault corre-
sponds to the source fault of the Noto Hanto earthquake.
: Noto Hanto earthquake, earthquake source fault, seismic reflection profiling, geo-
logic structure, central Japan
.
M . Sakai
ENE-WSW ; ;
; Ozawa
km
Yamada ; Sakai
*
Hiroshi Sato *, Shinji Kawasaki , Susumu Abe , Naoko Kato , Iwasaki Takaya , Tanio
Ito
et al.,
et al.,
et al., et al.,
Abstract
Key words
Seismic Reflection Profiling Across the Onshore Source
Area of the Noto Hanto Earthquake, Central Ja-
pan
+ , -
+
,
-
+ , , + + -
+ , , + +
-
2, ,**1 ,0/ ,1-
++- **-, + + +
,**1 0 3
#
+*
/1/
+ , 2 - , . + - ,
,**1
,**1
,**1 - ,/ 3 ., ,**+
0 3 ,**2
0* ,**/ ,**1 ,**1
,**1 ,**2
- + +*
,**2 ,**2
,**1
+
,**1
,**1
� � ���� � � �� � � �
�� � �
� � � �� � ��
� �� �
� �� � � �� � �� � �
��� �
�� � � ��
� ��� �
� � ��
� � � �� �� � �
� �
� �
����� � �� ���� !" �# $%&' ()�*+ �#,- ./ �0 ����� �! 12� 345 6�789 : ;! <� �= >0 ���? @ ,AB C �0 D � �E�F � G>0 ;HI C JKL ���� �M �!NOPQ�R � STUTVWTX-Y HZ [C \] ^, _C `a bcKL d/eH fgh ijHk l �m0 no�p Cq+ r Les r �t ��uc�� � J STUTVWTX-Y`*v [i_ �(),wxyh >0 j n�J ! ;zT{|�p ,} h~+q�
R �� � �H�0*�� s� h ��V���*0�TU� H�+q�� ,��./ �0 d� � �TU!� � �g �*0 � � : �
! � �� �()Le�5./05 Cq��� � :�q��� ./q ;���!@ , >0 �/e� �! � >0R �Cq��[��Cqno,~a ���{ TU� ¡ uc�� H¢£ �¤ ,} h~+qq� ��! ¥¦§ g¨©ª�� �*+ «./0 �� ª � ���{ TU
! z�¬���./ �0, �# ®¯ H¤ Cq � o°!±$%&' = !²Lh � Le³ ./ ´ H 0q� [C VµT¶� ·!0�� �¸ F �!¹ !º�»./ �( �;4¼½¶VµT¶h~0 VµT¶ !
��� � �� ��
� �� ��� �
� ������� � � � � � � �� � �� �� ! " #$ % &�# � � ' (� )
*+ , - �. / 0 �1 2 3 45 6 7 �8 7 9 : (� )�. �;< #$ = > � ?
- #$ � ��@ AB C+ �� �� DE 0 F E F G
H I � FG J �! � #$ � *+ #$ K L- M H N ? O
#$ + �� > 8� ��� � N P 0
Q R S #$ 4 # � J T�� � & �� & U
�
�� �
����
�� ��� ������
�
� � � � �
��
�� �
�
266
Fig. . Geological map showing the seismic line “Monzen ”.
Major geologic structure is after Editorial committee of civil engineering geologic map of Hokuriku ( ).
Pre-N : mainly pre-Neogene rocks with minor distribution of lower Miocene andesite.
Fig.
Kano ;
. km Fig.
Lopez and Ishiwatari,
ENE-WSW
Table
ENE-WSW Industrial Vehicle Interna-
tional EnviroVibe
m
Hz
et al.,
+ *2
+33*
+30/
+301 +33*
+
,**,
,**/
+333 3 +
+
,**,
+
+33* ,* 2 +**
,*
,
-
- +
�
���� �� � � �
� � �� � � � �
� � � � �
� � ��
� � �� � � � �
� � �� �� � �
� � �
� � �
��
� �
��
�� �
��
�
�
� �
����� �� ���� �� ��� �� ��� �� �� !" � ���� ��# $ � % &'()*+, �� -./ 0123 456 78 �� 9: ;<� =� > �� �� � �� �� � ?@�A B3 CD ��? �� � EF0.GHI �B3H"H �#;<� �J;�� ;<�K �� L � -./ �M �N �OEP L Q R� � ��� �S
TUVWXY�Z 0 [G�� \ ]L�N �� ^ �� � �� "H" ���� P �J;� _` 0. : �� �� L R� � ���
TUV� �Pa �� \ ]L�� bc -./ � ��� �S �� ^ ��d�e 0fgB3H-h i J �� � R�� "H-h jkl�m� bcd�_n3H"� L �op�p qp �r s t s� 23�uvwx��y z{|}�TUV�a ��
M ~ �� h� R � � � �� � ��� � �* 0.G��� �����mS �� jkl�m� � y�0� 78 ��
���Z �������p���� 7_��� �� �7� �� � ��� �7���Z�[2���Z�� �0 �� j�Wp�7K � ¡37¢S 0� £¤7_G�mWp ¥�¦�m9: 0§¨ �#h 9:©�K ��E[G�ª50 �H� «32�¬�®Y�9:S 7�p�� [2¯°��� � { {±S � : 9: ² 7 "H ; � �³7¤´� � E� 7µ/ �* LL 7K ��
) � ;< �*L�
: ¶· m�¸¹ ºpm »� �¼ : ½
7_G�
������ � � �
� � � � � �� � ��� � � �
� � � � � � � � � � �� � � � !"� #$%& '
� () *+ ,- + ./ � 0 1 234 � + 5 � 6- 7 �
./ 8 . 6 � � 6-19 : + +;< 2 5=4 �� () >?@ � 1 7 �
< � (- A A BCD :
E� F G *+: 1 � � H . . � 2 I �
JH � K L
M �� J 2N�
� O '3 2H. �P P2 Q � � � � 0 �
RS RS T ' �� �
I
U<V � � UW
� � ������
�
�
�
�
�
�
�
�
267
Table . Data acquisition parameters for the Monzen
seismic survey.
Fig. . Examples of shot gathers of the Monzen seismic survey.
A : a shot gather for reflection profiling at VP , B : a shot gather for refraction analysis at VP . Location of
shot points is shown in Fig. .
Fig. A
. . .
G-DAPS A
RP m
m
VP Fig.
B
RP VP
VP
RP km
VP
. km JGI Super X
Minimum Phase Conversion
Trace Edit
CMP
CMP Fig.
CMP : CMP : . m, :
. km
Gain Recovery
AGC
,**1
+
*2
, *2
,01 .3*
+
/ ,
1/ +** * / * 2 + +
. +
+ -10 +*
,/
.3* 1/
,.3 ,
,22 /0/ 1 +**
,.3 0*. +**
.3* /
,01 /
, /
+
+0./ / **
2 ,,
+,**
- ,
����� �� �� ���� ���� ����
� ��
� �� �
� �
� ��
� � � � � �� �� � � �
� � � � �� �
� � �� � � �� � � � �
� � � � ��� � � � � �
� �� � ��
� �
���� !"#$�%&' (&')*+),-./01 234)56�"7.89:;)���� !"#$�<=.>?: @A)BCD"7.EF1:G"HI J K LMN"7I J K OPQHRQS TUVW J K XYG"H
Z[\]/0^_)%`abcdefgX.hijk l)mcd%`' (&' nopqors.tuvwx9Q�y"z$� 7Q{7"{| .>6 no)}~.� /0.>?: �)�)\�);: gX��.p�no��o)rs ��� .��9�)��6_�J!"H.�1:. w��1:X) nopqo)rs � ��]/0
w�k ��o)��� ��9 � /0�)�"7)��\.F6:��]/0.)��� Z[\]/0)�"7w1_F6: >?: ����;:]/0�. /0 )�"7rs3¡ �¢F1 £srs3¡.>?:�rs¤¥| .F6 ¤¥
¦)§'�rs3¡.>?: ¤¥¨©ª�« rs3¡� ��]/0 �� ¬>?: ¤¥�)�"7�1_ ®¯°7"±²H.>6
/0 @A)®¯°7".¢F1¤¥XY¨©.³´1:rs3¡�µ?_8d¶:rs}~.F6_
�
�
�� �
����
� � � � �
�
�
� �
268
Fig. . Surface structure determined by time-term analysis.
(a) time-terms,
(b) velocities of second layer,
(c) topography and geometry of surface low velocity layer.
Fig. . Optimum stacking velocities determined by
velocity analysis.
Deconvolution
: :
: . : :
Time Valiant
Refraction Statics
mal Moveout NMO
Fig. V .
. km s V Residual Statics
. . km s m NMO
NMO
Velocity Analysis
Constant Velocity Stack CMP CMP Stack
CMP m Fig. Final Filtered Stack
NMO NMO Correction
Nor- Fig. A
-
.
,*** ,.*
* / .
- + , *
* 2 ,
+ 1 , 1 * .*
+** /**
. ,
/
��
����� �� � ���
�
� � �
� � � � � � �
� �
� � �
� � �
� � ��
�
� � �
� �
� � � �
�
� �
������ ��� ���� ���� ������ ! "#$ %&' �()� ���� *�+,- ./ ��0� 12 3 &'45678 ./ 9: � ; <8=>6?3 4' @AB0+,C������ D3EF & GH/+>IJK � !LMN3AO
P �Q���R+>$ � S �TU; VWXYZV[X 3\ ]NP^# 2 GH�3_`&P
!abQ>��Rc+ de f$ g �XYZ hi 2 3@ABD fj bQ>��Rc+k 3A4 bQ>��Rc+ lm�n+>o5pI#q�GH�3_`&P2 $ rs&PtL2 �u�/+> 34P ; <#$ v I&'wZM�'45 xY12bQ>��Rc+y z �{| YZq}~Xf� o5{|bQ>��Rc+��K f�& 2 ��3 4 v xY12 3 4P f �Q
' !a��y ��� z3AOP y ���R+>f 4PGH�3�oz���+8�a�$ I&P ^~YZ X X X�
o5 �;�� YZ fY1'$ X��;� �I�� �� � #� &PRc7�K X�N� &'�F X2 $ I�f�&' ; < f�5T�3AOP y S ���O'45 } ��X#w5V[Xf�4'$f�15�� $ %�� YZ�y I&P ��� � f�52 T�YZ YZ �X�a�3���7�� f ]N' �]NPK a2 �� &'45I¡ ]�P� ¢£�{|H�¤ ����¥78 3_`& ¦ f�&'v 3 ��x#$§p¨#�©ª�#��YOP�# }~��F !«;3_`&P ¬ ®¯ °�P±v {| �Q+���8��Q?3LMN5P±flm�$²³¦´a# µf #�P �;¶4f n+>&P·¸ y ¹fW �2 I&'º º�2 � ±Z�5 �� 3 »P
�7��H���h�; ¼�;I½ Z�'�F § q}~X�2 $ �;¦´a# I�OP
����� � �
� � ��� � � � �
� � � �� � �
� � � �� �
� � � �� �� � �
� � ��� � �� � �� � � � � � �
� � � �� �
� !� "# � $ % & " �
� � � � � �� � � � �
' () " �� � �$ � *
+� , �� - .* / �0 1 �
� 2 3% �
� �
� �
������
����� �
��
��
�
269
Fig. . Filtered stacked section and post stacked, migrated time section of the Monzen seismic line.
F-X : km s
: :
:
. . : Hz,
. . : Hz, . . :
Hz
Time Migration
:
Fig. B
Depth Conversion . km s
km s Fig.
Fig. A
m . km s . km s . km s
.
km s . km s
. km s . km s
. km s
km s km s km
. km s
,**1
/ *2
.3 .
1 +***
/** +322
* * * / ,/ -* // 0/
* / + * +2 ,- ./ // + * / * +* +* -/ ./
2*
/
+ 1
. 1
0
. * 2 , 2 - ,
, 2
- - /
, 2 - 1
, - ,
. /
. -
- .
- -
�
� �� � � �
��
� � �
� �
� �
�� �
�
�� � ���� ��� ���� ����
� �� �� �
� � � �� � � � �
� � � ��� �
� ��
�� � � �
� �� � �
�� �
�� � � � � �
� �� �
� ��� �
� �
� �
������ � !" #$ #$ $ % %&'(" )�*+,-�./ ���012 34567�8� 9 :;<'= >?9@ "ABCD�E � F GHI JKLH M�NG OPQ RS #0TUV" SF UVU=U �./ "E �0 W X2 Y FZ[GHI JF12 \ !F8U =] RS^_$�`!� Q abc�de" RS $" ! 01f" g+h5,iFj $"=k lOmn5,o HIpqQO l$�^_$r stIu='vOOw0 x0yz${='v " | F}Kk~ �� �N0 QU >?� YO FZ[GH # $"��� = Y F GH
)I'( )� Y �>?� �� �0���=�F��${H Y �>? �'( >?��
! �J $" RS � 0'�V �!�J� J� 9��QO S��" K �!l$ �N�XU Y �F � 0XH`!��r �_$ ��${H �� 0XH`!��$" RS $ ! deF ~03456708�QV]2 ~8��J
�!l$" '( �L� $" �I���$1HI��KLH % 0"�-���� � RS ��¡0" �0 zQO�¢£f9¤�
¥¦�*§+4§¨©0 :M�N�./ F QV Oª �&«¬�F Q ;k 0>?QO��9@UH )L(" � � ®�=¯�°�'(=2 QVUH RS � YJ $"~ 0 �N�XU Y �F ±KLH%�$1H | F}Kk~ �� �N� = Y FZ[Q² $" *+,-��-"J�³´I ¦0M� 0;k>?QV% �%&��Iµ �$1HN�%�F¶k./QO)IF·(LV]2 '( �_0" 0 �!>?QO Y
�� ¦-� ¸ ¹ F Q �� 0XH`!��$r ���0]UVr º�./»¼0½'LVUO F34567�8�9@G)I'( J� 9��
�� �
� � � � � � � � � �
� � � � � � � �� � �� ��
� � � � � � �� � � � � � �
� � � � �� � � �� �
� � �� � �� � �
� �� � �
� !" �� # $ � % � �
& �� � �� � � � ' � � � �( � ��!" ) � � *
� �) + , � � �
� �
� ��������� ����
�
��
�
� � � � �
� �
270
Fig. . Depth converted seismic section (A) and its geologic interpretation (B) of the Mozen seismic line. F and
F : inferred fault, Red and black broken lines : boundary of velocity layers deduced from the refraction analysis.
m, m
m
Fig. B CMP
CMP F ; Fig. B
. km CMP . km s
m . km s . km s,
. km s
CMP
Yamaji, CMP
; Sato and Amano, . km
Kano Fet al.,
0 +
,
1** /* ,**,
+0**
0 .** +,**
-
+ --* + 0
+ 1 -** .** - ,
1/* , 2 - 1
. +
+,** +0**
++** +*** -*
+33* +33+ . +
,
.
�
� ��
���������� ������
� � � � ��
� � � �� �
�
�� � �
� � � � � �� �
� � �� � �
� �� �� �
� � ��
��
� �
�� ����� � !" �#�$%� &'�� (��)*+� ,-��.�*/�01" ���23+�45678�9:;�<=>?@AB")* C%��� � D�EFGHI"*23J7�EFGH 23J7�K��*/��� LM� N��O�PQLM�RS �����)1H����TU�V�+WXR� ��#7 �������YZ*�[ \%]"^_`%�P(?ab%X"c�;?]
+WXR� de� �C+�P(LfgRXhX�i+Ig" �����������*�$EF*�jk ������lm�nopq� %] � LrHG+B"�s+ ��tu+vwR ���
���pq *� x �y�%z{B" | ���L}~�� ���� �7 `%� ���@A*��B"�s+ lm4�8L��B"��* C?�H1 ���R}~������������.�{B"�C+ �CmL4�*B"� ���� �s ����?&'01� lm28������|�@AL�����@A�CL ��C+��� z�N��%] |�@A*������ ����.�*���� )��%�|�@AGHM �e8��+��B"c�;?�X �8+&'01"01"�����zy? �G��y�*�R� ���2�z�K��%] ¡¢456�£¤¥¦§�y�� Jy�+#¨01RX" |�@A� EF ©�ª+Q«01���*&'01"P¬GH&'�� ���8+(�RX" ��?wR ®¯���� ���CGH&'01"���78��? N��«@*°±²1«@L³wRP ´µ¶L·i+]� lmvX�¸�¹º»�¼�½
�
� ���
� �
271
Fig. . Velocity model of the Monzen seismic line obtained by refraction analysis.
(a) Comparison between theoretical travel time curves (solid lines) and first arrival data (solid circles).
(b) Ray diagrams corresponding to the first arrivals from seven shot points.
(c) Velocity model with inferred P-wave velocities (in km/s).
F
F
F
m F
m
N E
N E km
km
Fig.
F
F
,**1
1 *2
+
+
,**1
+
-** ,
,**
,**1
,-
0* ./ ,
, ,
2
+
+
/
� � �� � �
� � ��� � � �
� �� �
�
� � � �� �� �� �� � �
� �� � �
�� � � � �
� �� �
� � � � �
� � �� � � � � � �� � �
��� � � � � �� ! "#$ % &'()*�+ *,+ -./01 2345 ( - 6 ( 789 -: ;�< 2= > *?
@ A B C '() (DE FGHI JKLMKN -234
OPQR % & -: & -:ST PT OPQR U VWXY=Z[V\] - >Z[^_`abbc'(& d D bV
� �� & b >e�fg h./V\(ij(k lmnopq b � b[ brsotam
b(u v2-: wxyz -:{|}
~�� � � Y=V\^_`a�A� �S � � % (��p+�A �1 [�� -2 �
� �� � � �
�� � �� � � �
�� �� � �
� � �� �
e� >e����� �i��i b >�a`� � �v2Z[V\]e|��� ��i(> ���� @ ¡$¢£ij( ¤¥¦§ i >� v2Y=¨© ª «¬V\ 1
be¢£«¬V\ ®¯v2Y=V\] @U?1 (?H°��±²��i ³i V\(? e 1 V\´�µ ¶ b( be¢£ >V\ ® ·¸2 bV\]� ¹ º �i »»e¼��½u ¢
��� � �� ��
� � � � ��� ���� �
� �� �� ���� � � � ��� ���� � �
��� ! " # ����$��% & �
���� � '� (�)* �+ , -��� ���� ' . � /0
'� 1 �2 3 �
4 � ��� ����� 56-����� 7
89:;� � 89��:;�: <
= >? ����8 �@ � A
B 1 C � 1� D E
F G A HD I1 � J 4- - ����� K
LI � 4 -MNO J
PQ -����� 6� K R � *S K
� �
�
�
�
�
�
�
� �
��
�
�
� � � � �
� � � � ��
� �� �
� � �
� �
� �
�
272
syn-rifting succession, northern Noto Peninsula, Japan :
Fig. . Comparison between geologic structure and aftershock distribution. Aftershock distri-
bution is after Sakai ( ) and Yamada ( ). The aftershocks were projected to
the plane, which is perpendicular to the strike of the source fault and passes through the center
of the seismic line (Line in Figure from Sato ), and rotated to the general strike
of the CMP line of the seismic section. On this figure the dip angle of source fault shows
apparent dip angle.
Evidence for short-term uplifting precedent to the
rapid opening of the Japan Sea, , .
.
p.
.
Lopez, C. J. and Ishiwatari, A., , Petrogenesis of the
tholeiitic basalt, calc-alkaline basaltic andsite and high
magnesian andesite lava succession of the Oligo-
Miocene Anamizu Formation in northeastern Noto Pen-
insula,central Japan, , .
no.
CD.
Ozawa, S., H. Yarai, M. Tobita, H. Une and T. Nishimura,
, Crustal deformation associated with the Noto.
Hanto Earthquake in in Japan,
, ..
Sakai, S., A. Kato, T. Iidaka, T. Iwasaki, E. Kurashimo, T.
Igarashi, N. Hirata, T. Kanazawa and the group for thep.
joint aftershock observation of the Noto Hanto
Earthquake, , Highly resolved distribution of after-.
shocks of the Noto Hanto Earthquake by a denseKano, K., T. Yoshikawa, Y. Yanagisawa, K. Ogasawara and
seismic observation, , .T. Danhara, , An unconformity in the early Miocene
:
:
et al. et al.
et al.,
Island Arc,
J. Min. Petrol. Sci.,
Earth Planets Space,
Earth Planets Space,
2
,**2 ,**2
+* + ,**1
+1* +2.
,**/
13+ 2+*
+30/ 1 / +
+ 2.
,**/
,20 ,33
,**,
2/ ++-
,**1 0+,**1 ,**1
-*+ -+,
+322,**2, ,0- ,00
,**1
3/ 32,**1 ,**1 0 /0, /00
+33*
133,**1+333
,**2,33 -*2,**1
2- 22,**,
+3 ,**1
+3
+33****+ ,**1
++
++.
+++
31
2,
.+
0*11
/-
0*
�
� �� �� � � � �
� � �� � �
� �� � � �
�� ���������������
�� � �� � � ! "# $ %&'( ������� )�*+ �,-./012 34� �567 89 :; �5<�= �� ���>?@ABC ��DE=FG
HIJKL MI&N OPQR SP T �UVW �XY Z[\ ��[\]^_`�abcdef�ghijk �lmn
HIJKL opqr s#Vt upvw xITy z�{w ;P|} u~�� MI&N SP T
� �
�
�
� �
� � � � � ��
� � � � �
� � � � �� � � �
273
.
Sato, H. and K. Amano, . Relationship between tecton- Yamada, T., K. Mochizuki, M. Shinohara, T. Kanazawa, S.
ics, volcanism, sedimentation and basin development, Kuwano, K. Nakahigashi, R. Hino, K. Uehira, T. Yagi, N.
Late Cenozoic, central part of Northern Honshu, Japan. Takeda and S. Hashimoto, , Aftershock observation
Sediment. Geology, , . of the Noto Hanto earthquake in using ocean bot-
tom seismometers, Earth Planets Space (in press).
Yamaji, A., , Rapid intra-arc rifting in Miocene north-
. east Japan, Tectonics, , .
Received January ,
Accepted March ,
,**1
+301 ,**1
,* + -03 -13
+33+
,**2
-,- -.- ,**1
,**+ +33*
2-2 2.2 -0/ -12
,+ ,**2
,**1 +1 ,**2
2,
1.
++* 3