Neogene strike-slip faulting in Sakhalin and the Japan Sea opening

Abstract

The paper describes structural data from a 2000km N-S dextral strike-slip zone extending from northern Sakhalin to the southeast corner of the Japan Sea. Satellite images, field data and focal mechanisms of earthquakes in Sakhalin are included in the interpretation. Since Miocene time the deformation in Sakhalin has been taken up by N-S dextral strike-slip faults with a reverse component and associated en-echelon folds. Narrow en-echelon Neogene basins were formed along strike-slip faults and were later folded in a second stage of deformation. A model is proposed of basin formation along extensional faults delimitating dominos between two major strike-slip faults, and subsequent counterclockwise rotation of the dominos in a dextral transpressional regime, basins becoming progressively oblique to the direction of maximum horizontal compression and undergoing shortening. The association of both dextral and compressional focal mechanisms of earthquakes indicates that the same transpressional regime still prevails today in Sakhalin. -from Authors