The primary coastline of the port was bedrock embayment and composed of Mesozoic granite.

三亚港原始岸线为基岩港湾海岸,由中生代花岗岩构成.

The nearby beaches may supply sediment for the embayment during storm surges, by causing bed-load and suspended-load transport of the beach material towards deeper waters.

胶州湾沙滩供沙的主要机制是通过风暴潮期间强烈的动力作用，使沙滩沉积物以悬移质、底移质形式向深水区扩散或搬运。