Small scale of mantle convection restricted in asthenosphere diverges in sea basins, converges in Okinawa Trough and Mariana Trough, and it can be generally analogized with isostatic gravity anomaly.

• 小尺度地幔流主要限于软流圈层内部 ,在各海盆分散 ,而在冲绳海槽和马里亚纳海槽则会聚 ,可与均衡重力异常类比。