Scientific Reports (Mar 2021)

Fast Holocene slip and localized strain along the Liquiñe-Ofqui strike-slip fault system, Chile

  • Luis Astudillo-Sotomayor,
  • Julius Jara-Muñoz,
  • Daniel Melnick,
  • Joaquín Cortés-Aranda,
  • Andrés Tassara,
  • Manfred R. Strecker

DOI
https://doi.org/10.1038/s41598-021-85036-5
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 10

Abstract

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Abstract In active tectonic settings dominated by strike-slip kinematics, slip partitioning across subparallel faults is a common feature; therefore, assessing the degree of partitioning and strain localization is paramount for seismic hazard assessments. Here, we estimate a slip rate of 18.8 ± 2.0 mm/year over the past 9.0 ± 0.1 ka for a single strand of the Liquiñe-Ofqui Fault System, which straddles the Main Cordillera in Southern Chile. This Holocene rate accounts for ~ 82% of the trench-parallel component of oblique plate convergence and is similar to million-year estimates integrated over the entire fault system. Our results imply that strain localizes on a single fault at millennial time scale but over longer time scales strain localization is not sustained. The fast millennial slip rate in the absence of historical Mw > 6.5 earthquakes along the Liquiñe-Ofqui Fault System implies either a component of aseismic slip or Mw ~ 7 earthquakes involving multi-trace ruptures and > 150-year repeat times. Our results have implications for the understanding of strike-slip fault system dynamics within volcanic arcs and seismic hazard assessments.