Key Facts
• January 1, 2024: Noto Peninsula earthquake caused liquefaction damage in Niigata City.
• Niigata City plans block-based liquefaction countermeasures to reduce future earthquake risks.
• March 26, 2026: Intention confirmation surveys mailed to about 180 landowners in Konan Ward’s Amano area.
• Target area covers approximately 250 hectares affected by liquefaction.
• Residents must bear 5,250 yen per tsubo (approx. 3.3 m²) and obtain unanimous landowner consent.
• Survey asks residents if they want “to implement,” “considering,” or “not implement” countermeasures.
• 58.7% of target neighborhood associations held explanatory meetings by March 2026.
• Trial construction to start June 2026 at Sonogi Kotobuki Park using groundwater lowering method.
• Trial includes groundwater pumping, drainage pipe installation, and simulated building weight tests over nearly one year.
• Technical challenges expected higher in sloped areas like Terao Ward compared to flat Amano area.
• Niigata City aims for full-scale construction by 2028, pending resident understanding and consent.
• Similar groundwater lowering experiments began in 2025 in Imizu City, Toyama Prefecture, with local resident observation.
• Residents express concerns over high costs, long construction period, and need for full consensus.
Summary
Following the 2024 Noto Peninsula earthquake, Niigata City is advancing block-based liquefaction countermeasures to mitigate future earthquake damage. The city began surveying landowners in a prioritized area of Konan Ward in March 2026, seeking their intentions on whether to proceed with costly measures requiring unanimous consent. The survey offers three options: implement, consider, or not implement, and asks about perceptions of the financial burden. Despite ongoing explanatory meetings, participation remains around 50-60%, and residents voice concerns about the high cost of 5,250 yen per tsubo and the lengthy timeline, with construction expected to start by 2028. Trial construction using groundwater lowering techniques will begin in June 2026 at Sonogi Kotobuki Park to evaluate effectiveness and ground stability. Technical difficulties are anticipated to be greater in sloped areas planned for future trials. Niigata City continues efforts to increase resident understanding and consensus, recognizing these as critical hurdles to realizing the project. Similar experiments in Toyama Prefecture provide a reference point for community engagement and technical validation.
