Земетресения с магнитуд от 4,5 или по-голям са достатъчно силни, за да се регистрират от всички сеизмографи по света.
| Описание | Магнитуд по Рихтер | Ефект | Честота | |
|---|---|---|---|---|
| Микро | По-малко от 2,0 | Микроземетресения, не се усещат. | Около 8 000 на ден | |
| Много слаби | 2,0–2,9 | Обикновено не се усещат, но се отчитат. | Около 1 000 на ден | |
| Слаби | 3,0–3,9 | Често се усещат, но рядко причиняват щети. | Около 49 000 годишно | |
| Леки | 4,0–4,9 | Усещат се трусовете. Често причинява щети. | Около 6 200 годишно | |
| Средни | 5,0–5,9 | Може да причини големи щети. | 800 годишно | |
| Силни | 6,0–6,9 | Нанасят сериозни щети в голям радиус. | 120 годишно | |
| Големи | 7,0–7,9 | Разрушителни в радиус около 100 км. | 18 годишно | |
| Много големи | 8,0–8,9 | Нанасят сериозни щети в радиус от стотици километри. | 1 годишно | |
| Изключително силни | 9,0–9,9 | Нанасят огромни щети в радиус от хиляди километри. Възможни са дори мащабни промени в релефа близо до епицентъра. | 1 за 5-10 години | |
| Глобална катастрофа | ≥ 10,0 | Напълно катастрофални за цели континенти и дори за целия свят. | Изключително рядка, 1 за хиляди години (неизвестна / може и невъзможно) |
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| Magnitude | Description | Mercalli intensity | Average earthquake effects | Average frequency of occurrence (estimated) |
|---|---|---|---|---|
| Less than 2.0 | Micro | I | Microearthquakes, not felt, or felt rarely by sensitive people. Recorded by seismographs.[16] | Continual/ several million per year |
| 2.0–2.9 | Minor | I to II | Felt slightly by some people. No damage to buildings. | Over one million per year |
| 3.0–3.9 | II to IV | Often felt by people, but very rarely causes damage. Shaking of indoor objects can be noticeable. | Over 100,000 per year | |
| 4.0–4.9 | Light | IV to VI | Noticeable shaking of indoor objects and rattling noises. Felt by most people in the affected area. Slightly felt outside. Generally causes none to minimal damage. Moderate to significant damage very unlikely. Some objects may fall off shelves or be knocked over. | 10,000 to 15,000 per year |
| 5.0–5.9 | Moderate | VI to VIII | Can cause damage of varying severity to poorly constructed buildings. At most, none to slight damage to all other buildings. Felt by everyone. Casualties range from none to a few. | 1,000 to 1,500 per year |
| 6.0–6.9 | Strong | VII to X | Damage to a moderate number of well-built structures in populated areas. Earthquake-resistant structures survive with slight to moderate damage. Poorly designed structures receive moderate to severe damage. Felt in wider areas; up to hundreds of miles/kilometers from the epicenter. Strong to violent shaking in epicentral area. Death toll ranges from none to 25,000. | 100 to 150 per year |
| 7.0–7.9 | Major | VIII or greater[17] | Causes damage to most buildings, some to partially or completely collapse or receive severe damage. Well-designed structures are likely to receive damage. Felt across great distances with major damage mostly limited to 250 km from epicenter. Significant death toll. | 10 to 20 per year |
| 8.0–8.9 | Great | Major damage to buildings, structures likely to be destroyed. Will cause moderate to heavy damage to sturdy or earthquake-resistant buildings. Damaging in large areas. Felt in extremely large regions. Death toll in the thousands. | One per year | |
| 9.0 and greater | Near or at total destruction - severe damage or collapse to all buildings. Heavy damage and shaking extends to distant locations. Permanent changes in ground topography. Death toll can surpass 10,000. | One per 10 to 50 years |
(Based on U.S. Geological Survey documents.)[18]
