PALAEOSTRESSES AND STRIKE-SLIP MOTION IN THE KOREAN STRAIT FROM THE EXAMPLE OF THE TSUSHIMA ISLANDS (SOUTHWEST JAPAN)

Fracturation analysis in the Tsushima islands (southwest Japan) brings information on the Tertiary tectonics of the Korean strait. A NW-SE c ompression affects the Middle Miocene intrusions and the Eocene to Low er Miocene turbidites. This late phase is correlated to a regional com pressional event dating from Upper Miocene to Pliocene, during which t he Tsushima Fault moved left-laterally. An early phase is responsible for the formation in the turbidites of right-lateral strike-slip fault s oriented parallel to the Tsushima Fault. These structures suggest an early right-lateral motion along the Tsushima Fault before Middle Mio cene.