High slip rate for a low seismicity along the Palu-Koro active fault in central Sulawesi (Indonesia) |
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| Authors: | Olivier Bellier Michel Sébrier Thierry Beaudouin Michel Villeneuve Régis Braucher Didier Bourlès Lionel Siame Eka Putranto & Indyo Pratomo |
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| Institution: | CEREGE (Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement), UMR CNRS 6635 –UniversitéAix-Marseille III, BP 80, Europôle Méditerranéen de l'Arbois, 13545 Aix en Provence Cedex 4, France,;UMR CNRS 8616 `ORSAYTERRE, Universitéde Paris-Sud, 91405 Orsay Cedex, France,;UMR-CNRS 6019, University de Provence, 13331 Marseille, France,;CEREGE, University Aix-Maseille III, France,;DGGMR/PPPG (Geological Research and Development Centre), Bandung, Indonesia |
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| Abstract: | In eastern Indonesia, the Central Sulawesi fault system consists of complex left-lateral strike-slip fault zones located within the triple junction area between the Pacific, Indo-Australian and Eurasian plates. Seismicity in Central Sulawesi documents low-magnitude shallow earthquakes related, from NW to SE, to the NNW-trending Palu-Koro (PKF) and WNW-trending Matano fault zones. Study of the active fault traces indicates a northward growing complexity in the PKF segmentation. Left-lateral displacement of 370 ± 10 m of streams incised within fans, whose deposition has been dated at 11 000 ± 2300 years, yields a calculated PKF horizontal slip rate of 35 ± 8 mm yr?1. This geologically determined long-term slip rate agrees with the far-field strike-slip rate of 32–45 mm yr?1 previously proposed from GPS measurements and confirms that the PKF is a fast slipping fault with a relatively low level of seismicity. |
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