hazard area; danger zone; no man's land
Refers to an area designated as dangerous due to natural disasters (flood, tsunami, etc.) or other hazards, where entry is restricted or warned against.
After the tsunami, the coastal area was designated as a hazard area.
Please do not enter the danger zone.
危険区域 is a more general term for a dangerous area, while 警戒区域 specifically implies an officially designated zone with warnings or restrictions, often in disaster contexts.
sediment-related disaster risk area
Compound of 警戒 (warning, caution) and 区域 (area, zone).