@article{fdi:010064630,
  title = {{P}aleoseismology and tectonic geomorphology of the {P}allatanga fault ({C}entral {E}cuador), a major structure of the {S}outh-{A}merican crust},
  author = {{B}aize, {S}. and {A}udin, {L}aurence and {W}inter, {T}. and {A}lvarado, {A}. and {M}oreno, {L}. {P}. and {T}aipe, {M}. and {R}eyes, {P}. and {K}auffmann, {P}. and {Y}epes, {H}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {P}allatanga fault ({PF}) is a prominent {NNE}-{SSW} strike-slip fault crossing {C}entral {E}cuador. {T}his structure is suspected to have hosted large earthquakes, including the 1797 {R}iobamba event which caused severe destructions to buildings and a heavy death toll (more than 12,000 people), as well as widespread secondary effects like landsliding, liquefaction and surface cracking. {T}he scope of this study is to evaluate the seismic history of the fault through a paleoseismological approach. {T}his work also aims at improving the seismotectonic map of this part of the {A}ndes through a new mapping campaign and, finally, aims at improving the seismic hazard assessment. {W}e show that the {PF} continues to the north of the previously mapped fault portion in the {W}estern {C}ordillera ({R}umipamba-{P}allatanga portion) into the {I}nter-{A}ndean {V}alley ({R}iobamba basin). {F}ield evidences of faulting are numerous, ranging from a clear geomorphological signature to fault plane outcrops. {A}long the western side of the {R}iobamba basin, the strike-slip component seems predominant along several fault portions, with a typical landscape assemblage (dextral offsets of valleys, fluvial terrace risers and generation of linear pressure ridges). {I}n the core of the inter-{A}ndean valley, the main fault portion exhibits a vertical component along the c. 100 m-high cumulative scarp. {T}he presence of such an active fault bounding the western suburbs of {R}iobamba drastically increases the seismic risk for this densely inhabited and vulnerable city. {T}o the east ({P}eltetec {M}assif, {C}ordillera {R}eal), the continuation of the {P}allatanga fault is suspected, but not definitely proved yet. {B}ased on the analysis of three trenches, we state that the {R}umipamba-{P}allatanga section of the {PF} experienced 4 (maybe 5) {H}olocene to {H}istorical strong events ({M}w > 7). {T}he coseismic behavior of the fault is deduced from the occurrence of several colluvial wedges and layers associated with the fault activity and interbedded within the organic black soil sequence. {A}ccording to a series of {C}-14 datings, we document that these events occurred during the last 6500 years. {T}he clear deformation of the shallowest layer (14{C}: 1633 {AD}) is most likely associated with the 1797 {R}iobamba earthquake. {A}fter retrodeforming one of the 3 trenches, we estimate coseismic vertical throws (0.70 to 0.90 m). {B}ecause of bad outcrop conditions, we could not determine the horizontal component of slip and we used the slip vector determined in a previous work with a tectonic geomorphology study. {A}ssuming this slip vector, we obtain total coseismic offsets between 3.5 and 4.5 m, indicative of earthquake magnitudes around c. {M}w 7.5. {T}he estimated recurrence time intervals range between 1300 and 3000 years, indicating an average slip rate of c. 2.5 mm/a for the {R}umipamba-{P}allatanga section of the fault.},
  keywords = {{E}cuador ; {P}allatanga fault ; {M}orphotectonics ; {P}aleoearthquake ; {F}ault slip rate ; {S}eismic hazard ; {EQUATEUR}},
  booktitle = {},
  journal = {{G}eomorphology},
  volume = {237},
  numero = {{SI}},
  pages = {14--28},
  ISSN = {0169-555{X}},
  year = {2015},
  DOI = {10.1016/j.geomorph.2014.02.030},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064630},
}