７－３　2004年新潟県中越地震

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1 04 Mid Niigata earthquake Earthquake Research Institute, University of Tokyo M M M M M.9 30km M ) 2 RMS P S P 3 S km 17km 3 M6 km 27 M6.1 Double-Difference 2)

2 4 km 3 4 km (M6.8) (18:34 M6.) /27 6 / ,000m tear fault km 2mm/ 1mm/ A-A' ) M

3 27 40 M ) Takeda, T., H. Sato, T. Iwasaki, N. Matsuta, S. Sakai, T. Iidaka and A. Kato, Crustal structure in the northern Fossa Magna region, central Japan, from refraction/wide-angle reflection data, Earth Planets Space (04). 2) Zhang, H., and C., Thurber, Double-Difference Tomography: the method and its application to the Hayward Fault, California, Bulletin of the Seismological Society of America, 93, (03). 3) 2 (1992). 4) : (04) ) : 1 132p ) : 1 4p ) : 1 177p ) 799p ) :, 60p, (02). ) :1:2,000 D.1-No ) : : (Wed, 17 Nov 04 08:14: ), 12) p.1992.

4 138 00' 38 00' ' ' ' 37 30' 37 00' 36 30' ' ' ' ' 1 Fig.1Location of permanent stations ( ) and temporal stations(, ) Fig.2Model of velocity structure (W:thick line, E:thin line).

5 Fig.3Hypocentral distribution. The main shock ( ) and some large aftershocks ( ) are shown.

6 4 Double-Difference Zhang ;Thurber, 03 P km/s Fig.4Depth section showing the P wave velocity structure and the relocated aftershocks derived from the double-difference tomography (Zhang and Thurber, 03). Gray circles denote the locations of the aftershocks, and the color contour shows the P wave velocity.

7 Mw 30 km km 1 m 9.0 **18 Nm 6.6 km km 0. m 3.0 **18 Nm 6.3 Fig.Change of Coulomb stress due to the main shock and the largest aftershock.

6 a: b: :04 :03 1992 04 03 Fig.6Bouguer anomaly map of Niigata and southern Tohoku district and the hypocentral location of the 04 Mid Niigata earthquake.

anomalies are after Geological Survey of Japan (1992). 7 1: 23 17 6 M6.82: 23 18 3 M6.33: 23 18 11 M6.04: 23 18 34 M6.: 27 40 M6.1a: b: c: 6)7)8) 9 4 Fig.

8 6 a: b: :04 : Fig.6Bouguer anomaly map of Niigata and southern Tohoku district and the hypocentral location of the 04 Mid Niigata earthquake. a: Shibata-Koide tectonic line, b: Kashiwazaki-Choshi tectonic line, red star: hypocenter of the 04 Mid Niigata earthquake, Blue star: hypocenter of the 03 Northern Miyagi earthquake, Bouguer anomalies are after Geological Survey of Japan (1992). 7 1: M6.82: M6.33: M6.04: M6.: M6.1a: b: c: 6)7)8) 9 4 Fig.7Geological structure and hypocentral distribution around the source area of the 04 Mid Niigata earthquake. 1: Main shock (October 23, 17:6' M6.8), 2: Aftershock (Oct. 23, 18:03' M6.3), 3: Aftershock (Oct. 23, 18:11' M6.0), 4: Largest aftershock (Oct. 23, 18:34 M6.), : Aftershock (Oct. 27, :40 M6.1), a: Obirou fault, b: Mikamachi fault, c: Suwa-toge flexure. Geological map is compiled after ), 6), 7) and 8), active fault is 9) and ), tilting of river terraces is after 4).

earthquake. Thick solid line represents an estimated source fault.

9 , 12 Fig.8Schematic diagram showing the crustal structure across the source faults of the 04 Mid Niigata earthquake. Thick solid line represents an estimated source fault. Circle: aftershock, triangle: site of drill hole projected onto cross section. The data of drill holes is after ) and 12). 9 Fig.9Schematic diagram showing the 3D view of the source faults (not in exact scale).

京都大学防災研究所年報第 60 号 A 平成 29 年 DPRI Annuals, No. 60 A, 2017 Generating Process of the 2016 Kumamoto Earthquake Yoshihisa IIO Synopsis The 2016 Kumamoto e

京都大学防災研究所年報第 60 号 A 平成 29 年 DPRI Annuals, No. 60 A, 2017 Generating Process of the 2016 Kumamoto Earthquake Yoshihisa IIO Synopsis The 2016 Kumamoto earthquake is a large intraplate earthquake that broke

７－３ 2004年新潟県中越地震

７－３　2004年新潟県中越地震