ACOUSTIC OBSERVATIONS OF FLUID MUD AND INTERFACIAL WAVES, HANGZHOU BAY, CHINA

By using an acoustic suspended sediment monitor (ASSM), layered struct ures were found in a proposed navigational channel at neap tide in Han gzhou Bay: downwards these are low concentration suspension; high conc entration suspension; and fluid mud. Acoustic images revealed four dif ferent frequencies of interfacial waves. Type I is low-frequency inter facial wave between low concentration suspension and high concentratio n suspension. Type II is low-frequency internal wave between high conc entration suspension and mobile fluid mud. Type III is cautiously inte rpreted as low-frequency interfacial wave between mobile fluid mud and stationary fluid mud, on which are superimposed Type IV high-frequenc y interfacial wave. These interfacial waves act as the secondary dynam ic forcing, which enhances local cohesive sediment resuspension and re -entrainment.