unit
of measure
conversions
equivalences
|
|
|
|
italiano
 |
english
 |
|
|
|
intensity
of the earthquake
| The
intensity of the earthquakes is valued according to the Richter
scale (Charles Francis Richter 26/4/1900 - 30/9/1985) or the
modified Mercalli scale (Giuseppe Mercalli 21/5/1850 - 19/3/1914).
The first scale furnishes an evaluation (magnitude)
of the quantity of freed energy, while the seconds scale assigns
a degree to the effects on the environment. In the 1902 Mercalli
proposed the first composed scale from 10 degrees, in succession
the Americans H.O. Wood and F. Neumann modified it adding
2 degrees at the end of adapt it to the constructive customs
in California conventions. For the same motive in Western
Europe is in use the MCS scale (Mercalli,
Cancani, Sieberg), but in Oriental Europe be used the MKS
scale (Medvedv, Karnik, Sponheuer). For a real comparison
of the intensity of the earthquakes, and not only of the effects,
has stayed introduced the scale of the magnitudo or Richter.
From notice that already the Cancani (1856-1904), had introduced
a gradation not empirical, assigning at 1° of the own scale
the value of 2.5 mm/s2, and at 12° the value of
10000 mm/s2. |
Richter
scale
| This
scale doesn't have divisions in degrees, inferior limits,
(if not of the tools) and superior. The appraisal of the energy
freed from a seism is associated to an index, by definition
magnitudo, it has drawn to divide the decimal logarithm of
the maximum ampleness of a shake and the logarithm of a shake
champion. The zero of the scale is equivalent to a freed equal
energy to 105 Joule. |
Mercalli
scale
| degree |
tremor |
description
|
| I
|
instrumental
|
People
do not feel any Earth movement. |
| II
|
lightest
|
A
few people might notice movement if they are at rest and/or
on the upper floors of tall buildings. |
| III
|
light
|
Many
people indoors feel movement. Hanging objects swing back and
forth. People outdoors might not realize that an earthquake
is occurring. |
| IV
|
mediocre
|
Most
people indoors feel movement. Hanging objects swing. Dishes,
windows, and doors rattle. The earthquake feels like a heavy
truck hitting the walls. A few people outdoors may feel movement.
Parked cars rock. |
| V
|
strongly
|
Almost
everyone feels movement. Sleeping people are awakened. Doors
swing open or close. Dishes are broken. Pictures on the wall
move. Small objects move or are turned over. Trees might shake.
Liquids might spill out of open containers. |
| VI
|
much
fort
|
Everyone
feels movement. People have trouble walking. Objects fall
from shelves. Pictures fall off walls. Furniture moves. Plaster
in walls might crack. Trees and bushes shake. Damage is slight
in poorly built buildings. No structural damage. |
| VII
|
strong
|
People
have difficulty standing. Drivers feel their cars shaking.
Some furniture breaks. Loose bricks fall from buildings. Damage
is slight to moderate in well-built buildings; considerable
in poorly built buildings. |
| VIII
|
violent
|
Drivers
have trouble steering. Houses that are not bolted down might
shift on their foundations. Tall structures such as towers
and chimneys might twist and fall. Well-built buildings suffer
slight damage. Poorly built structures suffer severe damage.
Tree branches break. Hillsides might crack if the ground is
wet. Water levels in wells might change. |
| IX
|
disastrous
|
Well-built
buildings suffer considerable damage. Houses that are not
bolted down move off their foundations. Some underground pipes
are broken. The ground cracks. Reservoirs suffer serious damage. |
| X
|
most
disastrous
|
Most
buildings and their foundations are destroyed. Some bridges
are destroyed. Dams are seriously damaged. Large landslides
occur. Water is thrown on the banks of canals, rivers, lakes.
The ground cracks in large areas. Railroad tracks are bent
slightly. |
| XI
|
catastrophic
|
Most
buildings collapse. Some bridges are destroyed. Large cracks
appear in the ground. Underground pipelines are destroyed.
Railroad tracks are badly bent. |
| XII
|
great
catastrophe
|
Almost
everything is destroyed. Objects are thrown into the air.
The ground moves in waves or ripples. Large amounts of rock
may move. |
|
magnitude
Richter
|
energy
joule
|
degree
Mercalli
|
|
<
3.5
|
<
1.6 E+7
|
I
|
|
3.5
|
1.6
E+7
|
II
|
|
4.2
|
7.5
E+8
|
III
|
|
4.5
|
4
E+9
|
IV
|
|
4.8
|
2.1
E+10
|
V
|
|
5.4
|
5.7
E+11
|
VI
|
|
6.1
|
2.8
E+13
|
VII
|
|
6.5
|
2.5
E+14
|
VIII
|
|
6.9
|
2.3
E+15
|
IX
|
|
7.3
|
2.1
E+16
|
X
|
|
8.1
|
>
1.7 E+18
|
XI
|
|
>
8.1
|
.
|
XII
|
earthquake severity
|
Richter
magnitude
|
earthquake
effects
|
|
less
than 3.5
|
Generally
not felt, but recorded.
|
|
3.5-5.4
|
Often
felt, but rarely causes damage.
|
|
under
6.0
|
At
most slight damage to well-designed buildings. Can
cause major damage to poorly constructed buildings
over small regions.
|
|
6.1-6.9
|
Can
be destructive in areas up to about 100 kilometers
across where people live.
|
|
7.0-7.9
|
Major
earthquake. Can cause serious damage over larger areas.
|
|
8
or greater
|
Great
earthquake. Can cause serious damage in areas several
hundred kilometers across.
|
|
|
magnitude
Richter
|
TNT
equivalent
|
|
-1.5
|
6
ounces
|
|
1
|
30
ounces
|
|
1.5
|
320
pounds
|
|
2
|
1
ton
|
|
2.5
|
4.6
tons
|
|
3
|
29
tons
|
|
3.5
|
73
tons
|
|
4
|
1000
tons
|
|
4.5
|
5100
tons
|
|
5
|
32000
tons
|
|
5.5
|
80000
tons
|
|
6
|
1
milion tons
|
|
6.5
|
5
milion tons
|
|
7
|
32
milon tons
|
|
7.5
|
160
milion tons
|
|
8
|
1
bilion tons
|
|
8.5
|
5
bilion tons
|
|
9
|
32
bilion tons
|
|
10
|
1
trilion tons
|
|
12
|
160
trilion tons
|
presumed
that one ounce of TNT exploded below ground yields
640 million ergs of seismic wave energy |
  
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