Wave-formed ripple

Their wavelength (periodicity) depends on the sediment grain size, water depth and water-particle orbits in the waves.

They are produced by bottom oscillations generated by passing breaker waves, which have unequal intensity in opposite directions.

[2] Wave-formed ripples indicate an environment with weak currents where water motion is dominated by wave oscillations.

Bi-directional ripples are rarely symmetrical due to the difference in force of the two directions, where as the wave formed or oscillation ripples form from the circular water movement pattern of water molecules.

Ripples are relatively small, elongated ridges that form on bed surfaces perpendicular to current flow.