The discovery of a conjugate system of faults in the Wharton Basin intraplate deformation zone

Satish C Singh (1) , Nugroho Hananto , Yanfang Qin (1) , Frédérique Leclerc (2) , Praditya Avianto (3) , Paul Tapponnier , Hélène Carton (1) , Shengji Wei , Adam B Nugroho , Wishnu A Gemilang , Kerry Sieh , Sylvain Barbot

1 IPGP - Institut de Physique du Globe de Paris
2 EOS - Earth Observatory of Singapore
3 LIPI - Indonesian Institute of Sciences

The deformation at well-defined, narrow plate boundaries depends on the relative plate motion, but how the deformation takes place within a distributed plate boundary zone remains a conundrum. This was confirmed by the seismological analyses of the 2012 great Wharton Basin earthquakes [moment magnitude (M w) 8.6], which suggested the rupture of several faults at high angles to one another. Using high-resolution bathymetry and seismic reflection data, we report the discovery of new N294°E-striking shear zones, oblique to the plate fabric. These shear zones are expressed by sets of normal faults striking at N335°E, defining the direction of the principal compressional stress in the region. Also, we have imaged left-lateral strike-slip faults along reactivated N7°E-oriented oceanic fracture zones. The shear zones and the reactivated fracture zones form a conjugate system of faults, which accommodate present-day intraplate deformation in the Wharton Basin.

Domaines: Sciences de la Terre; Planète et Univers [physics]

Satish C Singh, Nugroho Hananto, Yanfang Qin, Frédérique Leclerc, Praditya Avianto, et al.. The discovery of a conjugate system of faults in the Wharton Basin intraplate deformation zone. Science Advances , 2017, 3 (1), pp.e1601689. ⟨10.1126/sciadv.1601689⟩. ⟨hal-02378628⟩