Sieberg-Ambraseys sea-wave intensity scale Open new window

I. Very light

• Wave so weak as to be perceptible only on tide-gauge records.

II. Light

• Wave noticed by those living along the shore and familiar with the sea.

• On very flat shores generally noticed.

III. Rather strong

• Generally noticed.

• Flooding of gently sloping coasts.

• Light sailing vessels or small boats carried away on shore.

• Slight damage to light structures situated near the coast.

• In estuaries reversal of the river flow some distance upstream.

IV. Strong

• Flooding of the shore to some depth.

• Light scouring on man-made ground.

• Embankments and dikes damaged.

• Light structures near the coasts damaged.

• Solid structures on the coast injured.

• Big sailing vessels and small ships carried inland or out to sea.

• Coasts littered with floating debris.

V. Very strong

• General flooding of the shore to some depth.

• Breakwater walls and solid structures near the sea damaged.

• Light structures destroyed.

• Severe scouring of cultivated land and littering of the coast with floating items and sea animals.

• With the exception of big ships, all other type of vessels carried inland or out to sea.

• Big bores in estuary rivers.

• Harbour works damaged.

• People drowned.

• Wave accompanied by strong roar.

VI. Disastrous

• Partial or complete destruction of man-made structures for some distance from the shore.

• Flooding of coasts to great depths.

• Big ships severely damaged.

• Trees uprooted or broken.

• Many casualties.