Wills Site Classification

This is the site-type classification scheme developed by Wills et al. (2000, Bull. Seism. Soc. Am., vol. 90, p. 187-208).

The categories and their Vs30 equivalents are:

Site Class Vs30 range (m/sec)
B >760
BC 555-1000
C 360-760
CD 270-555
D 180-360
DE 90-270
E <180