Active Back-Arc Thrust in North West Java, Indonesia

Sonny Aribowo (1) , Laurent Husson (1) , Danny H. Natawidjaja , Christine Authemayou (2, 3) , Mudrik R. Daryono , Anggraini R. Puji , Pierre G. Valla (1) , Astyka Pamumpuni , Dadan D. Wardhana , Gino de Gelder (1) , Didiek Djarwadi , Manon Lorcery (1)

1 ISTerre - Institut des Sciences de la Terre
2 LGO - Laboratoire Géosciences Océan
3 IUEM - Institut Universitaire Européen de la Mer

The Java Back-arc Thrust scars the entire back-arc area of Java Island, but the faults' nature, timing, and activity remain partly elusive. Characterizing the structure and activity of the seismogenic Java Back-arc Thrust (historical earthquakes up to 7 M_w) is a cornerstone to evaluate associated geohazards. We focus on the western part of Java Back-arc Thrust that reaches the megalopolis of Jakarta. We combine morphotectonic data, seismic reflection, electric resistivity profiles, kinematic, structural field measurements, paleoseismological trenching, and sediment dating (optically stimulated luminescence and ¹⁴C). Our results suggest that the interplay between the faults, volcanoes, and sedimentary basin modulates the propagation of the fault system across and along-strike. The West Java Back-arc Thrust has been active from Pliocene to Recent, but with a laterally variable tempo and tectonic regime. While tectonic activity was sustained for longer times in the eastern part, the West Java Back-arc Thrust broke through the Jakarta Basin in the west, possibly only since the Late Pleistocene, and partitions into a network of immature transpressive structures. We conclude that the West Java Back-arc Thrust has a high seismic hazard that requires a careful risk evaluation along its trace, as it threatens the numerous infrastructures of the densely populated West Java.

Mots clés: active tectonics; back-arc thrust; volcanoes and faulting; morphotectonics; dating; Java

Domaines: Planète et Univers [physics]; Tectonique

Sonny Aribowo, Laurent Husson, Danny H. Natawidjaja, Christine Authemayou, Mudrik R. Daryono, et al.. Active Back-Arc Thrust in North West Java, Indonesia. Tectonics, 2022, 41, ⟨10.1029/2021TC007120⟩. ⟨insu-03779799⟩