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 fat shores generally noticed.
iii. Rather strong. Generally noticed. Flooding of gently sloping coasts. Light sailing vessels carried away on shore. Slight damage to light structures situated near the coast. In estuaries reversal of the river flow for 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 coast damaged. Solid structures on the coast injured. Big sailing vessels and small ships drifted inland or carried out to sea. Coasts littered with floating debris.
v. Very strong. General flooding of the shore to some depth. Quay-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.
(From: Ambraseys N.N – 1962. Data for the investigation of the seismic sea-waves in the Eastern Mediterranean. Bull. Seism. Society of America, vol.52, n.4, pp. 895-913. )
(from Papadopoulos G.A. and Imamura F. (2001)- A proposal for a new intensity scale. ITS 2001 Proceedings, Session 5, Number 5-1)
I. Not felt
(a) Not felt even under the most favorable circumstances.
(b) No effect.
(c) No damage.
II. Scarcely felt
(a) Felt by few people onboard small vessels. Not observed on the coast.
(b) No effect.
(c) No damage.
III. Weak
(a) Felt by most people onboard small vessels. Observed by few people on the coast.
(b) No effect.
(c) No damage.
IV. Largely observed
(a) Felt by all onboard small vessels and by few people onboard large vessels. Observed by most people on the coast.
(b) Few small vessels move slightly onshore.
(c) No damage
V. Strong
(a) Felt by all onboard large vessels and observed by all on the coast. Few people are frightened and run to higher ground.
(b) Many small vessels move strongly onshore, few of them crash into each other or overturn. Traces of sand layer are left behind on ground with favorable conditions. Limited flooding of cultivated land.
(c) Limited flooding of outdoor facilities (e.g., gardens) of near-shore structures.
VI. Slightly damaging
(a) Many people are frightened and run to higher ground.
(b) Most small vessels move violently onshore, crash strongly into each other, or overturn.
(c) Damage and flooding in a few wooden structures. Most masonry buildings withstand.
VII. Damaging
(a) Most people are frightened and try to run to higher ground.
(b) Many small vessels damaged. Few large vessels oscillate violently. Objects of variable size and stability overturn and drift. Sand layer and accumulations of pebbles are left behind. Few aquaculture rafts washed away.
(c) Many wooden structures damaged, few are demolished or washed away. Damage of grade 1 and flooding in a few masonry buildings.
VIII. Heavily damaging
(a) All people escape to higher ground, a few are washed away.
(b) Most of the small vessels are damaged, many are washed away. Few large vessels are moved ashore or crash into each other. Big objects are drifted away. Erosion and littering in the beach. Extensive flooding. Slight damage in tsunami control forest, stop drifts. Many aquaculture rafts washed away, few partially damaged.
(c) Most wooden structures are washed away or demolished. Damage of grade 2 in a few masonry buildings. Most RC buildings sustain damage, in a few damage of grade 1 and flooding is observed.
IX. Destructive
(a) Many people are washed away.
(b) Most small vessels are destroyed or washed away. Many large vessels are moved violently ashore, few are destroyed. Extensive erosion and littering of the beach. Local ground subsidence. Partial destruction in tsunami control forest, stop drifts. Most aquaculture rafts washed away, many partially damaged.
(c) Damage of grade 3 in many masonry buildings, few RC buildings suffer from damage grade 2.
X. Very destructive
(a) General panic. Most people are washed away.
(b) Most large vessels are moved violently ashore, many are destroyed or collide with buildings. Small boulders from the sea bottom are moved inland. Cars overturned and drifted. Oil spills, fires start. Extensive ground subsidence.
(c) Damage of grade 4 in many masonry buildings, few RC buildings suffer from damage grade 3. Artificial embankments collapse, port water breaks are damaged.
XI. Devastating
(b) Lifelines interrupted. Extensive fires. Water backwash drifts cars and other objects in the sea. Big boulders from the sea bottom are moved inland.
(c) Damage of grade 5 in many masonry buildings. Few RC buildings suffer from damage grade 4, many suffer from damage grade 3. XII. Completely devastating
(c) Practically all masonry buildings demolished. Most RC buildings suffer from at least damage grade 3.