Palu-Koro Fault

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The Palu-Koro Fault or Palu-Koro Fault System is a major active NNW-SSE trending left-lateral strike-slip fault zone on the island of Sulawesi in Indonesia. It caused the 2018 Sulawesi earthquake and tsunami.[1]

Geometry[]

It extends from near Dondowa, North Luwu Regency, in the south, where it links to the WNW-ESE trending . It continues northwards, heading offshore through the Gulf of Palu and passing to the west of the Minahassa Peninsula, before eventually linking with the . Although it is a strike slip fault, there are locally normal and thrust features and segments. Near Palu it forms the western side of the Palu Basin, a small pull-apart basin developed along the fault system.[2]

Regional setting[]

The fault forms the boundary between two of the major microblocks that form the island, the and the . The current slip rate along the Palu-Koro Fault is estimated to be in the range 30 to 40 millimetres (1.2 to 1.6 in) per year, compared to a long term slip rate of 40 to 50 millimetres (1.6 to 2.0 in) per year over the last 5 million years.[1][2][3]

Seismicity[]

The fault is known to be highly active and several historical earthquakes are thought to have occurred on this zone, in 1905, 1907, 1909, 1927, 1934, 1968, 1985 and 1993.[4] From trenching across the fault, three major earthquakes have been identified over the last 2,000 years, suggesting a recurrence interval for major earthquakes of about 700 years. That recurrence interval is insufficient to account for the long-term slip-rate, suggesting that either aseismic creep is important in this fault zone[3] or that other strands have been active, away from the main fault trace.[4]

References[]

  1. ^ a b Heriyanto, Devina. "Central Sulawesi quake: what we know so far". Jakarta Post. Retrieved 29 September 2018.
  2. ^ a b Socquet A.; Simons W.; Vigny C.; McCaffrey R.; Subarya C.; Sarsito D.; Ambrosius B.; Spakman W. (2006). "Microblock rotations and fault coupling in SE Asia triple junction (Sulawesi, Indonesia) from GPS and earthquake slip vector data". Journal of Geophysical Research: Solid Earth. 111 (B8). Bibcode:2006JGRB..111.8409S. doi:10.1029/2005JB003963.
  3. ^ a b Bellier O.; Sébrier M.; Beaudoin T.; Villeneuve M.; Braucher R.; Bourlès D.; Siame L.; Outranto E.; Pratomo I. (2001). "High slip rate for a low seismicity along the Palu-Koro active fault in central Sulawesi (Indonesia)". Terra Nova. 13 (6): 463–470. Bibcode:2001TeNov..13..463B. doi:10.1046/j.1365-3121.2001.00382.x.
  4. ^ a b Watkinson I.M.; Hall R. (2016). "Fault systems of the eastern Indonesian triple junction: evaluation of Quaternary activity and implications for seismic hazards" (PDF). In Cummins P.R.; Meilano I. (eds.). Geohazards in Indonesia: Earth Science for Disaster Risk Reduction. Geological Society, London, Special Publications. Vol. 441. pp. 71–120. doi:10.1144/SP441.8. ISBN 9781862399662. S2CID 132297395.
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