Optimal Intensity Measures for Probabilistic Seismic Stability Assessment of Large Open-Pit Mine Slopes under Different Mining Depths

Table 3

Adopted damage states for open-pit mine slopes in terms of FOS.

Damage states	DS1 (optimal)	DS2 (sufficient)	DS3 (moderate)	DS4 (minor)	DS5 (unacceptable)
Relative safety margins	Very high	High	Moderate	Low	None
Range of FOS	>2.0	1.4∼2.0	1.25∼1.4	1.0∼1.25	<1.0