Radon activity index | Expression of fault activity | |
KRn | Level | |
KRn > 20 | Ultra-high | Fault having strong activity expression |
20 ≥ KRn > 15 | High | Fault having clear activity expression |
15 ≥ KRn > 10 | Increased | Fault having activity expression or existence of strong tectonic fracture zone |
10 ≥ KRn > 5 | Medium | Fault having not clear activity expression or existence of fracture zone |
KRn ≤ 5 | Low | Fault having no activity expression |