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.

为了加深对活动断裂应力集中机制的认识，我们对活动断裂周围地壳的不均匀结构进行了详细的研究。此外，我们还研究了沿着活动断层发生的事件的震源机制和震源过程。地震层析成像研究揭示了沿着火山锋面在莫霍面下方广泛分布的部分熔融带。GPS观测表明，在火山前缘沿着还分布着一个板块转换方向的大收缩变形带。大地震震源区分布在这条大的收缩变形带周围。这些观测结果表明，地壳中的流体在弧形地壳的变形过程中起着重要的作用，并在其内部的地震发生。

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)

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。

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。

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)。

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)