Assertion: wave's wavelength | /r/CapableOf | form slight swell
Facets:
value: usually
type: DEGREE
Source sentences:
text: Tsunamis have a small wave height offshore, and a very long wavelength (often hundreds of kilometres long, whereas normal ocean waves have a wavelength of only 30 or 40 metres), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres (12 in) above the normal sea surface.