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II. Methods in Morphotectonics

II. Methods in Morphotectonics. 1- Identification of Active Faults 2 Determination of slip-rate on strike-slip faults 3- Determination of fold growth and shortening rates across a thrust fault system 4- Determinations of vertical deformation and extension rate across a rift system

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II. Methods in Morphotectonics

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  1. II. Methods in Morphotectonics 1- Identification of Active Faults 2 Determination of slip-rate on strike-slip faults 3- Determination of fold growth and shortening rates across a thrust fault system 4- Determinations of vertical deformation and extension rate across a rift system 5. Dating techniques

  2. 1.c Reverse and Thrust faults

  3. Satellite Mosaic and topography of Central Asia

  4. (Eastern termination of Tugulu antocline, North Tian Shan piemont, Dzoungar basin) • Note a clear fault cutting alluvial surfaces • The lobate geometry of the fault trace suggest thrust faulting (in addition to being associate with an anticline)

  5. Fault-bend fold(flat-ramp system)

  6. Thrust Fault are often blindFault-tip fold

  7. Foreland fold-and-thrust beltNorth Tien Shan

  8. Satellite Mosaic and topography of Central Asia

  9. Rivers entrenching a growing fold above an active thrust fault, China

  10. Satellite Mosaic and topography of Central Asia

  11. Growing fold above an active reverse fault, China Drainage is either force to entrench into the rising foldor is diverted

  12. Seismic ruptures of thrust faults

  13. ~90 mm/yr GPS measurement of interseismic strain across Taiwan (Yu et al, 1997; Hsu et al, 2003)

  14. TheMw, 7.6, ChiChi Earthquake 1999 (Western Taiwan) Surface ruptures extends over about 80km, with up to 12m of coseismic slip.

  15. Mw, 7.6, ChiChi Earthquake 1999 (Taiwan)

  16. Chichi A closer look

  17. Scarp landforms (from a study of the 1988 Armenian earthquake)

  18. The Mw, 7.6, ChiChi Earthquake 1999 (Western Taiwan) Surface ruptures extends over about 80km, with up to 12m of coseismic slip.

  19. Reverse fault in a strike-slip setting The “Big Bend”

  20. New Idria, 1982, Mw, 5.5 Coalinga 1983, Mw, 6.5 Kettelman Hills, 1985, Mw, 6.1 (Ekstrom and Stein, 1992, Stein and Ekstrom, 1992, Gusofski et al, 2007)

  21. Gusofski et al, 2007

  22. Gusofski et al, 2007

  23. 1994 1987 From JPL’s SRTM mission The 1987 Whitier Narrow and 1994 Northridge earthquakes alerted us to the presence of active blind thrusts within the metro region

  24. Irregular, sinuous, smooth topographic escarpment, Tripoli Photo from M. Daeron The city of Tripoli, in Lebanon, is built on an active thrust, forming an about 60m-high surface scarp

  25. Reverse faults: • Irregular, sinuous, smooth topographic escarpment (because collapse) • Most active reverse faults are blind (partly because they have a low dip-angle fault plane) • Yet, they are commonly associated to surface folding; such folding commonly forces rivers to deviate from their original course

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