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What is an earthquake?
An earthquake is a rapid movement of the Earth's surface due
to the sudden release of energy accumulated by two plates of
the Earth’s crust pushing against each other.
The rocks suddenly break along a fault because of all the
pressure accumulated inside the Earth in a place called
hypocenter or focus, i.e. the location below the earth’s
surface where the earthquake starts.
The place right above the focus (on top of the ground) is called
the epicenter of the earthquake.
CRUSTAL PLATES
INTERACTIONS
• Tectonic plate interactions are of three different
basic types:
• transform boundaries
• divergent boundaries
• convergent
(or subduction)
boundaries
TRANSFORM BOUNDARY
The Earth’s crust is neither created nor
destroyed and the plates only move
sideways.
DIVERGENT BOUNDARY
The plates move away
from each other and the
space created originates a
mountain range called the
mid-ocean ridge which
crosses a part of the
ocean for thousands of
kilometers.
An important example is
the “Rift Valley" in the East
of Africa.
CONVERGENT BOUNDARY
The plates move towards each other. In this
condition different phenomena happen
depending on the type of plates which come
into collision. Collisions can be between:
• two oceanic plates
• two continental plates
• an oceanic plate and a continental one
Collision between two continental plates
Collision between a continental
plate and an oceanic plate
Collision between two oceanic
plates
What are seismic waves?
- Seismic waves are propagating
vibrations that carry elastic
energy from the source of the
shaking outward in all
directions.
- They travel through the Earth's
layers;
- They are caused by the sudden
breaking of rock within the earth or
by an explosion. They are
recorded by seismographs.
The main types of seismic waves are:
- compressional or P (for primary) waves
- transverse or S (for secondary) waves
- surface waves
P-WAVES (primary)
This is the fastest kind of seismic wave. P-waves can
travel through solid rock and fluids, like water or the liquid
layers of the Earth. They push and pull the rock they
travel through. Subjected to a P wave, particles move in
the same direction that the wave is moving in, which is
the direction that the energy is travelling in. As they pass,
rocks are compressed and expanded continuously.
S-WAVES (secondary)
They are the second waves you feel in an earthquake. An Swave is slower than a P-wave and can only travel through
solid rock, not through any liquid medium. S-waves move
rock particles up and down, or side-to-side, i.e perpendicular
to the direction that the wave is travelling in.
SURFACE WAVES
An earthquake radiates P and S waves (longitudinal and
transverse waves) in all directions and the interaction of the
P- and S-waves with Earth's surface produces surface waves
in the Epicenter. In fact, surface waves propagate at the
surface and are responsible for the greatest damage.
TYPES OF EARTHQUAKES
• They are generally classified according to
their origin into four different categories:
• TECTONIC
• VOLCANIC
• COLLAPSE
• MICROSYSTEM
earthquakes
TECTONIC EARTHQUAKES
• TECTONIC earthquakes are the most
frequent and the most intense. They are
due to the release of the mechanical
energy accumulated gradually within the
earth crust.
VOLCANIC EARTHQUAKES
• VOLCANIC earthquakes come before and
with volcanic eruptions. They are rarely
related to tectonic ones, they are local
and, generally, less intense.
COLLAPSE EARTHQUAKES
• COLLAPSE eathquakes are the less
frequent and the most local and
superficial; are typical of karst terrain they
are caused by the collapse of underground
cavities.
MICROSYSTEMS
• MICROSYSTEM earthquakes are part of a
fourth category which includes all those
earthquakes of weak intensity, perceptible
only with seismographs.
MAJOR EPICENTERS
WORLDWIDE
Why is Italy a seismic land?
• Italy is situated on
the edge of the
convergence
between two major
plates, the African
and the Eurasian.
The movement
between these two
plates produces an
accumulation of
energy which is
released in the form
of earthquakes.
As we can see from the map, Italy
is located on a border of the plate,
to be precise between the African
plate to the south, and the
Eurasian plate to the north.
Areas with the greatest seismic risk in Italy
The Italian
peninsula is a
geologically very
active area, where
volcanic and seismic
activities are very
intense and
frequent.
Historically, the most
affected areas are
those along the
Apennines, from the
central Apennines to
Sicily.
MAJOR EARTHQUAKES IN
ITALY IN THE LAST 100 YEARS
PLACE
DATE
Messina
28 Dec
1908
7.2
37 sec
Calabria
8 Sep
1905
7.1
Friuli
6 May
15 Sep
1976
06 Mar
2009
Po Valley
Po Valley
Abruzzo
MAGNITUDE LENGTH DEAD
INJURED
HOMELESS
EPICENTER
43 sec
100,000
to
200.000
557
Strait of
Messina
3.000
300.000
Nicastro
(CZ)
6.4
5.9
50 scc
965
Thousands
45,000
Gemona/
Artegna (UD)
6.3
23 sec
309
1500
65,000
L’Aquila
20 May
2012
5.9
20 sec
7
50
5,000
Finale Emilia
(MO)
29 May
2012
5.7
18 sec
20
350
150,000
Medolla
(MO)
MESSINA- REGGIO CALABRIA
1908
PLACE
DATE
MAGNITUDE
LENGTH
DEAD
Messina
28th December 1908
7.2
37 seconds
100.000 to 200.000
INJURED
HOMELESS
EPICENTER
Strait of Messina
THE EARTHQUAKE
The ground shook for some 30 to 40
seconds, and the destruction was felt within
a 300-kilometer radius.
Moments after the earthquake, a 12-meter
tsunami struck nearby coasts, causing even
more devastation; 91% of structures in
Messina were destroyed and some 70,000
residents were killed.
CALABRIA 1905
PLACE
DATE
MAGNITUDE
LENGTH
DEAD
Calabria
8th September 1905
7.1
43 seconds
557
INJURED
HOMELESS
EPICENTER
Nicastro
THE EARTHQUAKE
The earthquake caused severe damage to
buildings and infrastructure already deficient,
ravaging the land. Most of the damage and
casualties were due to the seismological effects
which induced landslides, cracks, sliding soil,
liquefaction of sandy soil and the change in the
water regime on an area covering more than
6,000 kmq.
Three years after the earthquake, the rebuilding
and repair of the damaged houses began. Most
people lived in ill-equipped shacks.
FRIULI 1976
PLACE
DATE
MAGNITUDE
LENGTH
Friuli-Gemona
6th May 1976
11th-15th September 1976
6.4 (May), 5.6 (September)
50 seconds
DEAD
993
INJURED
2607
HOMELESS
80.000
EPICENTER
Gemona-Artegna-Venzone
THE EARTHQUAKE
The most affected area was the north of Udine. The damages of the
earthquake in May 1976 were amplified by two other shocks in September. The
damages were very serious for the particular conditions of the ground, the
position of the affected villages, almost all situated on top of the hills and the
advanced age of the buildings.
ABRUZZO 2009
Place
Abruzzo
Date
8 April 2009
Magnitude
Length
th
from 5.8 to 6.3
23 sec
Dead
309
Injured
1500
Homeless
65.000
Epicenter
L'Aquila
Before…
After…
THE EARTHQUAKE
The earthquake caused many victims and much damage. Most of
L'Aquila's medieval structures, but also many of its modern buildings,
were damaged.
Criticism was also applied to poor building standards that led to the
failure of many modern buildings in a known earthquake zone.
EMILIA 2012
Place
Date
Magnitude
Length
Po valley
th
20
th
st
29 31 May
rd
3 June 2012
5.9, 5.8, 4.2, 5.3
20 seconds
Dead
45
Injured
400
Homeless
20,000
Epicenter
various,
near Modena
BEFORE and AFTER
A church near Modena
Clock Tower, 1213, Finale Emilia
Castello delle Rocche, Finale Emilia
THE EARTHQUAKE
The shocks were felt in the northern and central Italy especially in the
province of Modena and they caused the most damages on 20th and
29th May.
At least 100 structures of historical significance were damaged or
destroyed. Many churches in towns around the epicentre suffered
damage. There was also significant damage to factories and
agricultural land in the region.
CONCLUSION
The risk of earthquakes in Italy is a major concern as in
many other countries. There is not a lot we can do to avoid
this type of disasters, but what we can certainly do is focus
our attention on the topic and improve safety.
This is what we should do:
• build safer buildings and schools to reduce the risk of
collapse.
• learn the correct behaviour at school and at the
workplace at the moment of the earthquake
• put a lot of effort in order to create a more sensitive and
conscious society and to educate the new generations to
the importance of solidarity towards those communities
which are affected by natural disasters.
We strongly believe that all countries should
work together to create a network of
knowledge, aid and action, in order to be
present immediately in affected areas and
so to reduce the consequences of the
earthquake.
With the Erasmus+ Project
‘Red Roof’ we are giving
our small contribution 
This project has been funded with support
from the European Commission.
This publication reflects the views only of the
authors, and the Commission cannot be held
responsible for any use which may be made
of the information contained therein.