[M-GI31] 地球掘削科学

[MGI31-05] 掘削と地球物理データを利用した間隙水圧と水理特性のモニタリングとモデリング

★招待講演

*辻 健¹ (1.東京大学大学院　工学系研究科)

キーワード：間隙水圧、モニタリング、モデリング、スロー地震、デジタル岩石物理

Pore pressure plays significant role in numerous earth processes such as seismic activity, volcanic phenomena, and landslides. It should be further considered in energy resource and carbon-neutral projects like CCS. Borehole data serves as a reliable source for acquiring precise information on pore pressure and hydraulic parameters. Here we showed the study of pore pressure or stress state estimation in the Nankai subduction zone based on the drilling and geophysical data. The comprehensive analysis allows us to characterize pore pressure conditions in both slow- and fast-earthquake regions along the plate boundary fault. Furthermore, the integration of seismic and drilling data has enabled the interpretation of the role of tectonic backstop that could influence earthquake magnitudes.
The temporal variation of pore pressure or stress state can be also identified by recent monitoring technology. To assess dynamic pore pressure behaviors, we have developed a monitoring system utilizing ambient noise. The monitoring system has been applied to identify changes of pore pressure related to earthquakes and volcanic activities at a high temporal resolution (~1 day). To further enhance spatial resolution for monitoring localized events, we have developed a continuous seismic source that can be installed in boreholes. In this presentation, we also show the results derived from such new monitoring and modeling technologies.