Definition of downthrow in English:

downthrow

verb

[WITH OBJECT]Geology
  • Displace (a rock formation) downward.

    • ‘The eastern and southeastern margins of the basin are marked by a major normal fault system comprising the Mochras, Tonfanau and BaIa faults, which downthrows the Cardigan Bay Basin against the Lower Palaeozoic Welsh Massif.’
    • ‘The overall effect at the present level of exhumation is shown diagrammatically in Figure 2c. Along many of the major faults, older rocks at late diagenetic grade are downthrown against younger rocks at higher grades.’
    • ‘The sedimentary record in the Taranaki Basin indicates that during the Late Cretaceous to Early Tertiary, the Cape Egmont and Manaia Fault Zones behaved as normal faults downthrowing to the east.’
    • ‘An exception is the Waikato Fault, which is downthrown to the north.’
    • ‘The contact between the Tertiary sedimentary sequence and the Samail ophiolite on the Batinah coastal plain is in many places a WNW-striking normal fault, downthrown toward the Gulf of Oman.’

noun

Geology
  • A downward displacement of rock strata.

    • ‘In southern Andrée Land, the contact is obscured by a later extensional fault with downthrow to the east that cuts obliquely across the strike of the high-grade Krummedal sequence.’
    • ‘The exploration geologist or geophysicist searching for these resources would be able to estimate that greater reserves would be preserved on the downthrow side of the fault, in contrast to its upthrow side.’
    • ‘Kinematic indicators for main phase deformation fabrics consistently demonstrate a sinistral sense of displacement with a minor southeasterly component of downthrow.’
    • ‘We use these values to estimate the maximum downthrow of the Skinos fault as 1.12 km from basic trigonometry.’
    • ‘The close proximity of the Isle of Wight-Purbeck fault zone probably also had an effect on Wealden sedimentation in the Wcssex Basin, as the downthrow on these faults decreases to the west.’

Pronunciation:

downthrow

/ˈdounTHrō/