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Several
intensity scales are used for various natural disasters
so as to categories the level of damage.
- Hurricanes
- The Saffir Simpson Scale
- Tornadoes
- The Fujita Scale
- Earthquakes
- The Modified Mercalli Scale & The Richter Scale
- Volcanic
Eruptions - The Volcanic Explosivity Index
Hurricanes - The Saffir Simpson
Scale
| Category |
Category Description |
Level of Damage |
1 |
Wind
Speed: 74 - 95 MPH
Storm Surge: 4 - 5 Feet Above Normal |
Primary
damaged to unanchored mobile homes, shrubbery, and
trees. Some coastal road flooding and minor pier
damage. Little damage to building structures. |
2 |
Wind
Speed: 96 - 110 MPH
Storm Surge: 6 - 8 Feet Above Normal |
Considerable
damage to mobile homes, piers, and vegetation. Coastal
and low-lying escape routes flood 2 - 4 hours before
arrival of hurricane center. Buildings sustaiin
roofing material, door, and window damage. Small
craft in unprotected moorings break moorings. |
3 |
Wind
Speed: 111 - 130 MPH
Storm Surge: 9 - 12 Feet Above Normal |
Mobile
homes destroyed. Some structural damage to small
homes and utility buildings. Flooding near coast
destroys smaller structures; larger structures damaged
by floating debris. Terrain continously lower than
5 feet. ASL may be flooded up to 6 miles inland.
|
4 |
Wind
Speed: 131 - 155 MPH
Storm Surge: 13 - 18 Feet Above Normal |
Extensive
curtainwall failures with some complete roof structure
failture on small residences. Major erosion of beaches.
Major damage to lower floors of structures near
the shore. Terrain continously lower than 10 feet.
ASL may flood (and require mass evacuations) up
to 6 miles inland. |
5 |
Wind
Speed: Over 155 MPH
Storm Surge: Over 18 Feet Above Normal |
Complete
road failure on many homes and industrial buildings.
Some complete building failures. Major damage to
lower floors of all structures located less than
15 feet ASL and within 500 yards of the shoreline.
Massive evacuation of low ground residential areas
may be required. |
Tornadoes - The Fujita Scale
| Category |
Category
Description |
Level
of Damage |
F-0 |
Gale
Tornado
40 - 72 MPH |
Chimneys
damaged; branches broken off trees; shallow-rooted
trees uprooted; sign boards damaged. |
F-1 |
Moderate
Tornado
73 - 112 MPH |
Roof
surfaces peeled off; mobile homes pushed off foundations
or overturned; moving autos pushed off roads. |
F-2 |
Significant
Tornado
113 - 157 MPH |
Roofs
torn off frame houses; mobile homes demolished;
box cars pushed over; large trees snapped or uprooted;
light-object projectiles generated. |
F-3 |
Severe
Tornado
158 - 206 MPH |
Roofs
and some walls torn off well-constructed houses;
trains overturned; most trees in forest uprooted;
heavy cars lifted off the ground and thrown. |
F-4 |
Devastating
Tornado
207 - 260 MPH |
Well-constructed
houses leveled; structures with weak foundations
relocated; cars thrown and large projectiles generated. |
F-5 |
Incredible
Tornado
261 - 318 MPH |
Strong
frame houses lifted off foundations and carried
considerable distance to disintegrate; automobile-sized
projectiles hurtle through the air in excess of
100 yards; trees debarked; other incredible phenomena
expected. |
Earthquakes - The Modified Mercalli
Scale & The Richter Scale
The Modified Mercalli Scale |
Level of Damage |
The Richter Scale |
1-4 |
Instrumental
to Moderate |
No
damage. |
</=
4.3 |
5 |
Rather
Strong |
Damage
negligible. Small, unstable objects displaced or
upset; some dishes and glass ware broken. |
4.4
- 4.8 |
6 |
Strong |
Damage
slight. Windows, dishes, glassware broken. Furniture
moved or overturned. Weak plaster and masonry cracked. |
4.9
- 5.4 |
7 |
Very
Strong |
Damage
slight-moderate in well-built structures; considerable
in poorly-built structures. Furniture and weak chimneys
broken. Masonry damaged. Loose bricks, tiles, plaster,
and stones will fall. |
5.5
- 6.1 |
8 |
Destructive |
Structure
damage considerable, particularly to poorly built
structures. Chimneys, monuments, towers, elevated
tanks may fail. Frame houses moved. Trees damaged.
Cracks in wet ground and steep slopes. |
6.2
- 6.5 |
9 |
Ruinous |
Structural
damage severe; some will collapse. General damage
to foundations. Serious damage to reservoirs. Underground
pipes broken. Conspicuous cracks in ground; liquefaction. |
6.6
- 6.9 |
10 |
Disastrous |
Most
masonry and frame structures/foundations destroyed.
Some well-built wooden structures and bridges destroyed.
Serious damage to dams, dikes, embankments. Sand
and mud shifting on beaches and flat land. |
7.0
- 7.3 |
11 |
Very
Disastrous |
Few
or no masonry structures remain standing. Bridges
destroyed. Broad fissures in ground. Underground
pipelines completely out of service. Rails bent.
Widespread earth slumps and landslides. |
7.4
- 8.1 |
12 |
Catastrophic |
Damage
nearly total. Large rock masses displaces. Lines
of sight and level distorted. |
>
8.1 |
Volcanic Eruptions - The Volcanic
Explosivity Index
Category |
Category
Description |
| 0 |
Non-Explosive
(Hawaiian)
Plume: < 100 m/Volume: > 1000 m3 |
| 1 |
Gentle
(Hawaiian - Strombolian)
Plume: 100 - 1000 m/Volume: >10,000 m3 |
| 2 |
Explosive
(Strombolian - Vulcanian)
Plume: 1 - 5 km/Volume: > 1,000,000 m3 |
| 3 |
Severe
(Vulcanian)
Plume: 3 - 15 km/Volume: > 10,000,000 m3 |
| 4 |
Cataclysmic
(Vulcanian - Plinian)
Plume: 10 - 25 km/Volume: > 100,000,000 m3 |
| 5 |
Paroxysmal
(Plinian)
Plume: >25 km/Volume: > 1 km3 |
| 6 |
Colossal
(Plinian - Ultraplinian)
Plume: > 25 km/Volume: > 10 km3 |
| 7 |
No
Adjectival Description
Plume: > 25 km/Volume: > 100 km3 |
| 8 |
No
Adjectival Description
Plume: > 25 km/Volume: > 1,000 km3 |
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