Study on stresss concentration mechanism on active faults

活动断层应力集中机制研究

• 批准号: 11440128
• 负责人: HASEGAWA Akira
• 金额: $ 5.76万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440128/
• 关键词: Active faults; Seismic tomography; Bright spot; Inland earthquakes; Seismic scatterer; Crustal structure; Fluids; Thermal structure; 地震波トモグラフイ

We have performed a detailed investigation on inhomogeneous structure of the crust around active faults aiming to improve our understanding of stress concentration mechanism on active faults. Moreover, we have investigated focal mechanisms and source processes of events occurring along active faults.Seismic tomography studies revealed a partial melting zone extensively distributed beneath the Moho along the volcanic front. GPS observations show that a zone of large ocontraction deformation in the plate conversion direction is distributed also along the volcanic front. Large earthquake focal areas are distributed aroud this large contraction deformation zone. These observations suggest that fluids in the crust play an important role in the deformation process of the arc crust and in the earthquake generation within it.

我们已经对围绕有效断层的地壳的不均匀结构进行了详细的研究，旨在提高我们对活动断层的应力浓度机制的理解。此外，我们已经研究了沿活动断层发生的事件的焦点机制和源过程。视觉断层扫描研究揭示了一个部分熔化区，该区域沿火山界广泛分布在Moho下方。 GPS的观察表明，在板转换方向上的大量吸收变形区域也沿火山锋分布。大地震焦点区域分布在这个较大的收缩变形区。这些观察结果表明，地壳中的流体在弧形地壳的变形过程和其中的地震产生中起着重要作用。

项目成果

Nakajima,J.: "Moho depth variation in the central part of northeastern Japan estimated from reflected and converted waves"Phys.Earth Planet.Int.. 130. 31-47 (2002)

Nakajima,J.：“根据反射波和转换波估计的日本东北部中部莫霍面深度变化”Phys.Earth Planet.Int.. 130. 31-47 (2002)

Nakajima, J., Matsuzawa, T., Hasegawa, A., Zhao, D.: "Seismic imaging of arc magma and fluids under the central part of northeastern Japan"Tectonophysics. 341. 1-17 (2001)

中岛 J.、松泽 T.、长谷川 A.、赵 D.：“日本东北部中部下方弧岩浆和流体的地震成像”构造物理学。

Nakamura,A.: "Temporal variations of seismic wave velocity associated with 1998 M6.1 Shizukuishi earthquake"PAGEOPH. 159. 1183-1204 (2002)

Nakamura,A.：“与 1998 年 M6.1 雫石地震相关的地震波速度的时间变化”PAGEOPH。

Nakamura,A.: "P-wave velocity structure of the crust and its relationship to the occurrence of the 1999 Izmit,Turkey earthquake and aftershocks"Bull.Seismol.Soc.Am.. 92. 330-338 (2002)

Nakamura,A.：“地壳纵波速度结构及其与 1999 年土耳其伊兹米特地震和余震发生的关系”Bull.Seismol.Soc.Am.. 92. 330-338 (2002)

Matsuzawa, T.: "Characteristic small-earthquake sequence off Sanriku, northeastern Honshu, Japan"Geophys.Res.Lett.. 29・11. 38-1-38-4 (2002)

Matsuzawa, T.：“日本本州东北部三陆附近的特征性小地震序列”Geophys.Res.Lett.. 29・11 (2002)。