Analysis of gravity anomalies in the Ulleung Basin (East Sea/Sea of Japan) and its implications for the crustal structure of rift-dominated back-arc basin

摘要

Highlights?The crustal structure of rift-dominated back-arc basins are not well-known because very often they are covered by thick sediments from continent. However, the prevailing thought is that a significant variation exists in crustal thickness.?Detailed analysis of marine gravity anomaly in the Ulleung Basin shows that the crust is abnormally thick (12?km) and its thickness is uniform (varying by only ±1?km) within the basin center.?Our finding is consistent with the Yamato Basin which is also situated close to the volcanic arc.AbstractThe Ulleung Basin (UB), one of three major basins in the East Sea/Sea of Japan, is considered to represent a continental-rifting end-member of back-arc basin system, but is much less understood compared to the nearby Yamato Basin (YB) and Japan Basin (JB). This study examines the gravity anomalies of the UB since the variation in crustal thickness can provide important insights on the mode of extension during basin opening. Our analysis shows that the Moho depth (from the sea