▪ I. downthrow
(ˈdaʊnθrəʊ)
1. A throwing or being thrown down. rare.
| 1615 Catascopes in Farr S.P. Jas. I (1848) 352 Wars, the canker of estate, Hel's image and al commonweale's down⁓throw. 1891 Times 21 Oct. 5/3 Unable to take his down⁓throw philosophically. |
2. Geol. The depression of strata below the general level on one side of a fault. (Originally a miners' term.) Also attrib.
| 1858 A. C. Ramsay Geol. Struct. Merioneth, etc. 5 Down the Bala valley..there runs a great fault. It is a down⁓throw to the north-west. 1882 Geikie Geol. Sk. 282 A true fault with an upthrow and downthrow side. 1889 J. Croll Stellar Evol. 54 About a mile E.S.E. of Beddgelert, there is a fault with a downthrow of 5000 feet. |
▪ II. downthrow, v.
(stress variable)
[f. down adv. + throw v.]
† 1. (Formerly at down adv. 36.) trans. To throw down; to usurp or overthrow. Obs.
| 1563 Myrrour for Magistrates ii. f. C. xxviiiv, Downthrow we strayt his sellie nephewes twaye. 1581 N. Burne Disput. f. 43v, Inducing subiectis to oppres and dounthrau thair maisters. |
2. intr. Geol. To undergo a downthrow (downthrow n. 2). Also with the magnitude of the downthrow as quasi-object. Cf. *downthrown ppl. a.
| 1971 Nature 19 Feb. 538/1 The major faults branching from the Gregory rift in these areas..almost always downthrow eastwards. 1975 Ibid. 25 Sept. 300/2 During the Cretaceous,..the South African continent was subjected to strong vertical movements, resulting in peripheral faults downthrowing 18,000 m towards the contiguous ocean basins. |