@article{fdi:010090114,
  title = {{C}ontinental block motion in the {N}orthern {A}ndes from {GPS} measurements},
  author = {{J}arrin, {P}. and {N}ocquet, {J}ean-{M}athieu and {R}olandone, {F}. and {A}udin, {L}aurence and {M}ora-{P}aez, {H}. and {A}lvarado, {A}. and {M}othes, {P}. and {A}udemard, {F}. and {V}illegas-{L}anza, {J}. {C}. and {C}isneros, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{N}orthwestern {S}outh {A}merica is a plate boundary zone where the {N}azca, {C}aribbean and {S}outh {A}merican plates interact to produce a wide area of active continental deformation from the {G}ulf of {G}uayaquil (latitude 3°{S}) to {V}enezuela. {P}revious studies have identified a average 2000-km-long continental sliver, referred as the {N}orth {A}ndean {S}liver ({NAS}), squeezed between the {N}azca, {C}aribbean and {S}outh {A}merican plates and escaping at average 1 cm-yr-1 northeastward with respect to {S}outh {A}merica. {S}ubduction of the {N}azca {P}late beneath the {NAS} has produced a sequence of large and great earthquakes during the 20th century along the coast of {E}cuador and {C}olombia. {L}arge crustal earthquakes up to magnitude 7.7 have been documented along the proposed eastern boundary of the {NAS}. {H}owever, active tectonics data, historical and recent earthquakes all indicate active fault systems within the {NAS}, possibly resulting from the interaction of several tectonic blocks. {H}ere, we derive an extensive horizontal velocity field using continuous and episodic {GNSS} data from 1994 to 2019.9, covering northern {P}eru, {E}cuador, {C}olombia, {P}anama and {V}enezuela. {W}e model the {GNSS} velocity field using a kinematic elastic block approach that simultaneously solves for rigid tectonic block rotations and interseismic coupling along the subduction interfaces and along major crustal faults. {I}n contrast to previous results that considered a single rigid {NAS}, our dense {GNSS} velocity field demonstrates that the {NAS} undergoes significant internal deformation and cannot be modelled as single rigid block. {W}e find that block kinematics in the northern {A}ndes are well described by the rotation of 6 tectonic blocks, showing increasing eastward motion from south to north. {T}he {E}astern boundary of the sliver is defined by a right-lateral transpressive fault system accommodating 5.6-17 mm-yr_1 of motion. {F}ragmentation of the {NAS} occurs through several fault systems with slip rates of 2-4 mm-yr-1. {S}low reverse motion is found across the sub-{A}ndean domain in {E}cuador and northern {P}eru at 2-4 mm-yr-1, marking a transitional area between the {NAS} and stable {S}outh {A}merica. {I}n contrast, such a transitional sub-{A}ndean domain does not exist in {C}olombia and western {V}enezuela. {A}t the northwestern corner of {C}olombia, fast (average 15 mm-yr-1) eastward motion of the {P}anama block with respect to the {NAS} results in arc-continent collision. {W}e propose that the {U}ramita fault and {E}astern {P}anama {D}eformed {Z}one define the current {P}anama/{NAS} boundary, accommodating 6 and 15 mm-yr-1 of relative motion, respectively. {A} fraction of the {P}anama motion appears to transfer northeastward throughout the {S}an {J}acinto fold belt and as far east as longitude average 75°{W}. {A}long the {C}aribbean coast, our model confirms, slow active subduction at average 4.5 mm-yr-1 along the {S}outh {C}aribbean {D}eformed {B}elt offshore northern {C}olombia and a relatively uniform rate of average 1-2 mm-yr-1 offshore northern {V}enezuela. {A}long the {N}azca/{NAS} subduction interface, interseismic coupling shows a first-order correlations between highly locked patches and large past earthquake ruptures. {T}hese patches are separated by narrow zones of low/partial coupling where aseismic transients are observed. {C}ompared to previous studies, our interseismic coupling model highlights the presence of deep coupling down to 70 km in {E}cuador.},
  keywords = {{P}late motions ; {S}atellite geodesy ; {S}outh {A}merica ; {N}orthern {A}ndes ; {E}lastic block model ; {AMERIQUE} {DU} {SUD} ; {ANDES}},
  booktitle = {},
  journal = {{G}eophysical {J}ournal {I}nternational},
  volume = {235},
  numero = {2},
  pages = {1434--1464},
  ISSN = {0956-540{X}},
  year = {2023},
  DOI = {10.1093/gji/ggad294},
  URL = {https://www.documentation.ird.fr/hor/fdi:010090114},
}