Site Class Definitions

Classification A

Hard rock with 10 ft (3 m) or less of soil overburden.

Classification B

Competent rock with moderate fracturing and weathering with 10 ft (3 m) or less of soil overburden.

Classification C

Very dense soil, soft rock or highly fractured and weathered rock.

Classification D

Stiff soil.

Classification E

Weak soil (excluding site class F)

Classification F

Soils vulnerable to potential failure or collapse under seismic loading.