Multiscale topographic features of the seamounts in the Yap-Caroline area of West Pacific

Multiscale topography of seamounts is helpful for understanding the geomorphic processes on different scales in the formation and evolution of seamounts and may provide clues for the study on geodynamic processes relating to plate subduction. Based on the high-resolution bathymetric data of Yap-Caroline area collected by R/V “Kexue” of the Institute of Oceanology, Chinese Academy of Sciences, the morphologic features and surface roughness of 42 seamounts in the study area have been analyzed by statistical methods, with focuses on the phenomenon and genesis of multiscale features of seamounts. The result demonstrates that the morphologic parameters and multiscale features of seamounts in different tectonic environments vary significantly. Seamounts in the Parece Vela Basin have larger height-to-basal-radius ratio and smaller flatness than those in the Sorol Trough. Different linear relationships between morphologic parameters imply that seamounts in the two regions have undergone different morphologic evolution processes. Multiscale analysis results suggest that the amplitudes of large characteristic scale (6～14 km) of seamounts in the Parece Vela Basin is not significant, and small-scale geomorphological processes have greater influence on the modification of seamount landscapes in this region. The linear relationship between roughness and volume of seamounts in the Sorol Trough might result from the discrepancy in formation times. Seamounts formed earlier have gone through more tectonic activities and small-scale geomorphologic processes, which resulted in rougher surface characteristics.