Morphological characteristics and geological significance of seamounts in the southern Kyushu-Palau Ridge areas

The quantitative morphology study of volcanic seamount helps to understand the seamount evolution and intrinsic relationship between seamount morphology and geodynamics. High-resolution seabed topography data of 40 volcanic seamounts in the southern Kyushu-Palau Ridge and adjacent areas were used to analyze statistically the seamount morphology and the influence on sedimentation dynamics of bottom flow by spectral and sequence stratigraphy analyses. Results show that the average height of seamounts in the study area is 1374 m, the average volume is 100 km³, the aspect ratio is 0.21±0.09, and the flatness is 0.16±0.18. The height of seamounts in the northern Central Basin Rift and the southern Kyushu-Palau Ridge show a good linear correlation with the bottom radius, while the correlation between seamounts in the southern Central Basin Rift is poor. The aspect ratio of seamounts in the southern Central Basin Rift is significantly greater than that in the northern Central Basin rift due probably to complicated stress fields under regional tectonic frames. By summarizing four volcanic evolution models, we found that the seamounts in the study area fit the model that they grow with proportional increase in summit height and base diameter, which could be explained by intermittent volcanic eruptions leading to proportional development on the top and flanks.