Looking for the meaning or definition of the word underdrag? Here's what it means.
Noun
(geology) The tensilestress exerted by an overthrust rock mass upon overlying rocks which themselves are not under compressive thrusting stress and therefore tend to be stretched and broken by normal faulting.
Verb
(transitive) To exert pull on the underside of (something).
(intransitive) To undergo a pull from the underside.