downthrow
n. 投下;陷落;坍陷
例句
This is the formula for a thick vertically faulted slab with such a large throw that the downthrow side makes no contribution to the gravitational force.
这是有垂直断层的厚板体的公式,其断层的落差是这样大,以致下落翼对重力场没有什么影响。