Development of new underground fracture imaging technology using groundwater sound

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19858
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Hirosaki University
• Principal Investigator: Ioka Seiichiro 弘前大学, 地域戦略研究所, 教授 (40598520)
• Co-Investigator(Kenkyū-buntansha): 若狭 幸 弘前大学, 地域戦略研究所, 准教授 (40442496)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 地下水 / 断裂 / 流水音

Outline of Final Research Achievements

It has been suggested that groundwater sound measurements in lava flow areas are effective for detecting the presence of water flowing underground. Groundwater sound measurements were conducted around springs where air bubbles existed, however, the sound of bursting bubbles was not detected. We attempted to use the groundwater sound measurements as a method of detecting the existence of hot springs that are thought to be flowing out from the underground fracture structures in collapsed areas. Although the sound of groundwater was observed, its presence could not be confirmed in the vicinity. In addition, groundwater sound measurements were performed on a riverbed in a collapsed area where many boulders had been deposited, and the existence of a complex underground water infiltration mechanism was demonstrated. We believe that the aforementioned results demonstrate that groundwater sound measurements can provide information on the path of groundwater in lava flow and collapsed areas.

Free Research Field

地熱水文学，地熱水文地球化学

Academic Significance and Societal Importance of the Research Achievements

透視できない地下断裂構造の評価手法の一つとして，断裂構造の存在が推定される場や気泡が存在する湧水の近傍で地下流水音の観測を実施した結果，地下流水音は地下を流れている水の経路を示唆していることが本研究を通して示された。断裂構造の推定には至らなかったが，溶岩流定着地域や山地の崩壊地で目視できない地下の水の流動経路について地下流水音の観測は有用であることが示され，崩壊地などでの地下の水の流動把握の利用が考えられた。