활동적 배호상 해분의 비대칭적 지형에 관한 연구

Asymmetric topography of active young back-arc basins

Active young back-arc basins such as Mariana, Havre, Lau, Manus and East Scotia basins have asymmetric topography of two types in respect to the spreading axis. The arc-trench wings of Mariana Trough, Lau basin and Havre Trough are shallower toward the active arc, whereas those of Manus and East Scotia basins are nearly symmetric to the opposite wings. The other asymmetry which shows the spreading axis deviated form the geographic axis toward the active arc is observed in each basin. Active young back-arc basins show a large variety of asymmetry rates ranging from the lowest East Scotia Basin to the highest Mariana Trough. The asymmetric topography of these young back-arc basins seems to be caused by the rollback rate of downgoing slab under the basin. As the rollback rate increases, the asymmetry rate systematically decreases.