Japan Meteorological Agency seismic intensity scale

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The Japan Meteorological Agency seismic intensity scale (震度 shindo) is a measure used in Japan and Taiwan to indicate the strength of earthquakes. Unlike the Richter magnitude scale (which measures the total magnitude of the earthquake, and represents the size of the earthquake with a single number) the JMA scale describes the degree of shaking at a point on the Earth's surface. As a result, the measure of the earthquake varies from place to place, and a given quake may be described as "shindo 4 in Tokyo, shindo 3 in Yokohama, shindo 2 in Shizuoka".

The JMA operates a network of 180 seismographs and 600 seismic intensity meters^[1] and provides real-time earthquake reports to the media and on the internet.^[2]

[edit] JMA scale explanation

The JMA Scale runs from 0 to 7, with 7 being the strongest. Sometimes roman numerals are used, as in the Mercalli Intensity Scale; however this is not the usual practice in Japan. The real-time reports are calculated automatically from measurements of ground acceleration. The JMA reports the shindo based on the ground acceleration.

Shindo scale^[3]
Magnitude (Japanese Name)	People	Indoor situations	Outdoor situations	Wooden houses	Reinforced-concrete buildings	Lifelines	Ground and slopes	Peak ground acceleration
0 (0)	Imperceptible to people.							Less than 0.008 m/s²
1 (1)	Felt by only some people in the building.							0.008–0.025 m/s²
2 (2)	Felt by most people in the building. Some people awake.	Hanging objects such as lamps swing slightly.						0.025–0.08 m/s²
3 (3)	Felt by most people in the building. Some people are frightened.	Dishes in a cupboard rattle occasionally.	Electric wires swing slightly.					0.08–0.25 m/s²
4 (4)	Many people are frightened. Some people try to escape from danger. Most sleeping people awake.	Hanging objects swing considerably and dishes in a cupboard rattle. Unstable ornaments fall occasionally.	Electric wires swing considerably. People walking on a street and some people driving automobiles notice the tremor.					0.25–0.80 m/s²
5-lower (5弱)	Most people try to escape from a danger. Some people find it difficult to move.	Hanging objects swing violently.Most Unstable ornaments fall. Occasionally, dishes in a cupboard and books on a bookshelf fall and furniture moves.	People notice electric-light poles swing. Occasionally, windowpanes are broken and fall, unreinforced concrete-block walls collapse, and roads suffer damage.	Occasionally, less earthquake-resistant houses suffer damage to walls and pillars.	Occasionally, cracks are formed in walls of less earthquake-resistant buildings.	A safety device cuts off the gas service at some houses. On rare occasions water pipes are damaged and water service is interrupted. (Electrical service is interrupted at some houses)	Occasionally, cracks appear in soft ground. and rockfalls and small slope failures take place in mountainous districts.	0.80–1.40 m/s²
5-upper (5強)	Many people are considerably frightened and find it difficult to move.	Most dishes in a cupboard and most books on a bookshelf fall. Occasionally, a TV set on a rack falls, heavy furniture such as a chest of drawers falls, sliding doors slip out of their groove and the deformation of a door frame makes it impossible to open the door.	In many cases, unreinforced concrete-block walls collapse and tombstones overturn. Many automobiles stop because it becomes difficult to drive. Occasionally, poorly-installed vending machines fall.	Occasionally, less earthquake-resistant houses suffer heavy damage to walls and pillars and lean.	Occasionally, large cracks are formed in walls, crossbeams and pillars of less earthquake-resistant buildings and even highly earthquake-resistant buildings have cracks in walls.	Occasionally, gas pipes and / or water mains are damaged.(Occasionally, gas service and / or water service are interrupted in some regions)	Occasionally, cracks appear in soft ground. and rockfalls and small slope failures take place in mountainous districts.	1.40–2.50 m/s²
6-lower (6弱)	Difficult to keep standing.	A lot of heavy and unfixed furniture moves and falls. It is impossible to open the door in many cases.	In some buildings, wall tiles and windowpanes are damaged and fall.	Occasionally, less earthquake-resistant houses collapse and even walls and pillars of highly earthquake-resistant houses are damaged.	Occasionally, walls and pillars of less earthquake-resistant buildings are destroyed and even highly earthquake-resistant buildings have large cracks in walls, crossbeams and pillars.	Gas pipes and / or water mains are damaged.(In some regions, gas service and water service are interrupted and electrical service is interrupted occasionally.)	Occasionally, cracks appear in the ground, and landslides take place.	2.50–3.15 m/s²
6-upper (6強)	Impossible to keep standing and to move without crawling.	Most heavy and unfixed furniture moves and falls. Occasionally, sliding doors are thrown from their groove.	In many buildings, wall tiles and windowpanes are damaged and fall. Most unreinforced concrete-block walls collapse.	Many, less earthquake-resistant houses collapse. In some cases, even walls and pillars of highly earthquake-resistant houses are heavy damaged.	Occasionally, less earthquake-resistant buildings collapse. In some cases, even highly earthquake-resistant buildings suffer damage to walls and pillars.	Occasionally, gas mains and / or water mains are damaged.(Electrical service is interrupted in some regions. Occasionally, gas service and / or water service are interrupted over a large area.)	Occasionally, cracks appear in the ground, and landslides take place.	3.15–4.00 m/s²
7 (7)	Thrown by the shaking and impossible to move at will.	Most furniture moves to a large extent and some jumps up.	In most buildings, wall tiles and windowpanes are damaged and fall. In some cases, reinforced concrete-block walls collapse.	Occasionally, even highly earthquake-resistant buildings are severely damaged and lean.	Occasionally, even highly earthquake-resistant buildings are severely damaged and lean.	(Electrical service gas service and water service are interrupted over a large area.)	The ground is considerably distorted by large cracks and fissures, and slope failures and landslides take place, which occasionally change topographic features.	Greater than 4 m/s²