Annex H(Clause 5.1.11)

MSK 1964 Intensity Scale

H-1 The following description shall be applicable.

a) Type of Structures (Buildings)

1. Type A — Building in field-stone, rural structures, un-burnt brick houses, clay houses

2. Type B — Ordinary brick buildings, buildings of large block and prefabricated type, half timbered structures, buildings in natural hewn stone

3. Type C — Reinforced buildings, well-built wooden structures

b) Definition of Quantity

1. Single, few : About 5 percent

2. Many : About 50 percent

3. Most : About 75 percent

c) Classification of Damage to Buildings

Classification Damage Description

Grade 1 Slight damage Fine cracks in plaster; fall of small pieces of plaster

Grade 2 Moderate Small cracks in walls; damage fall of fairlylarger pieces of plaster; pantiles slip off; cracks in chimneys parts of chimney fall down

Grade 3 Heavy damage Large and deep cracks in walls; fall of chimneys

Grade 4 Destruction Gaps in walls; parts of buildings may collapse; separate parts of the buildings lose their cohesion; and inner walls collapse

Grade 5 Total damage Total collapse of the buildings

H-2 MSK Intensity Scale

H-2.1 The following introductory letters (i), (ii) and (iii) have been used throughout the intensity scales (I to XII), describing the following:

i) Persons and surroundings,

ii) Structures of all kinds, and

iii) Nature.

I Not Noticeable

i) The intensity of the vibration is below the limits of sensibility; the tremor is detected and recorded by seismograph only.

ii) —

iii) —

II Scarcely Noticeable (Very Slight)

i) Vibration is felt only by individual people at rest in houses, especially on upper floors of buildings.

ii) —

iii) —

III Weak, Partially Observed

i) The earthquake is felt indoors by a few people, outdoors only in favourable circumstances. The vibration is like that due to the passing of a light truck. Attentive observers notice a slight swinging of hanging objects.

ii) —

iii) —

IV Largely Observed

i) The earthquake is felt indoors by many people, outdoors by few. Here and there people awake, but no one is frightened. The vibration is like that due to the passing of a heavily loaded truck. Windows, doors, and dishes rattle. Floors and walls crack. Furniture begins to shake. Hanging objects swing slightly. Liquid in open vessels are slightly disturbed. In standing motor cars the shock is noticeable.

ii) —

iii) —

V Awakening

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i) The earthquake is felt indoors by all, outdoors by many. Many people awake. A few run outdoors. Animals become uneasy. Buildings tremble throughout. Hanging objects swing considerably. Pictures knock against walls or swing out of place. Occasionally pendulum clocks stop. Unstable objects overturn or shift. Open doors and windows are thrust open and slam back again. Liquids spill in small amounts from well-filled open containers. The

PART 6 STRUCTURAL DESIGN — SECTION 1 LOADS, FORCES AND EFFECTS

sensation of vibration is like that due to heavy objects falling inside the buildings.

ii) Slight damages in buildings of Type A are possible.

iii) Slight waves on standing water. Sometimes changes in flow of springs.

VI Frightening

i) Felt by most indoors and outdoors. Many people in buildings are frightened and run outdoors. A few persons loose their balance. Domestic animals run out of their stalls. In few instances, dishes and glassware may break, and books fall down, pictures move, and unstable objects overturn. Heavy furniture may possibly move and small steeple bells may ring.

ii) Damage of Grade 1 is sustained in single buildings of Type B and in many of Type A. Damage in some buildings of Type A is of Grade 2.

iii) Cracks up to widths of 10 mm possible in wet ground; in mountains occasional landslips: change in flow of springs and in level of well water are observed.

VII Damage of Buildings

i) Most people are frightened and run outdoors. Many find it difficult to stand. The vibration is noticed by persons driving motor cars. Large bells ring.

ii) In many buildings of Type C damage of Grade 1 is caused; in many buildings of Type B damage is of Grade 2. Most buildings of Type A suffer damage of Grade 3, few of Grade 4. In single instances, landslides of roadway on steep slopes: crack in roads; seams of pipelines damaged; cracks in stone walls.

iii) Waves are formed on water, and water is made turbid by mud stirred up. Water levels in wells change, and the flow of springs changes. Sometimes dry springs have their flow restored and existing springs stop flowing. In isolated instances parts of sand and gravelly banks slip off.

VIII Destruction of Buildings

i) Fright and panic; also persons driving motor cars are disturbed. Here and there branches of trees break off. Even heavy furniture moves and partly overturns. Hanging lamps are damaged in part.

ii) Most buildings of Type C suffer damage of Grade 2, and few of Grade 3. Most buildings

of Type B suffer damage of Grade 3. Most buildings of Type A suffer damage of Grade 4. Occasional breaking of pipe seams. Memorials and monuments move and twist. Tombstones overturn. Stone walls collapse.

iii) Small landslips in hollows and on banked roads on steep slopes; cracks in ground up to widths of several centimetres. Water in lakes become turbid. New reservoirs come into existence. Dry wells refill and existing wells become dry. In many cases, change in flow and level of water is observed.

IX General Damage of Buildings

i) General panic; considerable damage to furniture. Animals run to and fro in confusion and cry.

ii) Many buildings of Type C suffer damage of Grade 3, and a few of Grade 4. Many buildings of Type B show a damage of Grade 4 and a few of Grade 5. Many buildings of Type A suffer damage of Grade 5. Monuments and columns fall. Considerable damage to reservoirs; underground pipes partly broken. In individual cases, railway lines are bent and roadway damaged.

iii) On flat land overflow of water, sand and mud is often observed. Ground cracks to widths of up to 100 mm, on slopes and river banks more than 100 mm. Furthermore, a large number of slight cracks in ground; falls of rock, many landslides and earth flows; large waves in water. Dry wells renew their flow and existing wells dry up.

X General Destruction of Buildings

i) —

ii) Many buildings of Type C suffer damage of Grade 4, and a few of Grade 5. Many buildings of Type B show damage of Grade 5. Most of Type A has destruction of Grade 5. Critical damage to dykes and dams. Severe damage to bridges. Railway lines are bent slightly. Underground pipes are bent or broken. Road paving and asphalt show waves.

iii) In ground, cracks up to widths of several centimetres, sometimes up to 1 m, parallel to water courses occur broad fissures. Loose ground slides from steep slopes. From river banks and steep coasts, considerable landslides are possible. In coastal areas, displacement of sand and mud; change of water level in wells; water from canals, lakes, rivers, etc, thrown on land. New lakes occur.

XI Destruction

i) —

ii) Severe damage even to well-built buildings, bridges, water dams and railway lines. Highways become useless. Underground pipes destroyed.

iii) Ground considerably distorted by broad cracks and fissures, as well as movement in horizontal and vertical directions. Numerous landslips and falls of rocks. The intensity of the earthquake requires to be investigated specifically.

XII Landscape Changes

i) —

ii) Practically all structures above and below ground are greatly damaged or destroyed.

iii) The surface of the ground is radically changed. Considerable ground cracks with extensive vertical and horizontal movements are observed. Falling of rock and slumping of river banks over wide areas, lakes are dammed; waterfalls appear and rivers are deflected. The intensity of the earthquake requires to be investigated specially.