UNIT 6 1 Seismic Engineering and disaster …Seismic Engineering and disaster Management 1 SYLLABUS...
Transcript of UNIT 6 1 Seismic Engineering and disaster …Seismic Engineering and disaster Management 1 SYLLABUS...
UNIT 6
Seismic Engineering and disaster
Management
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SYLLABUS
6.1 Introduction of seismic engineering and its
application civil engineering designs
6.2 Features of disasters such as Floods,
Earthquakes, Fires, Epidemics, Gas/radioactive
leaks etc.
6.3 Management and mitigation of above disasters
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6.1 INTRODUCTION OF SEISMIC
ENGINEERING AND ITS
APPLICATION CIVIL ENGINEERING DESIGNS
Earthquake engineering or Seismic
engineering is a branch of engineering that
searches for ways to make structures, such as
buildings and bridges, resistant to earthquake
damage.
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CONT…
Seismic engineers aim to develop building
techniques that will prevent any damage in a
minor quake and avoid serious damage or
collapse in a major shake.
It is the scientific field concerned with protecting
society, the natural environment, and the man-
made environment from earthquakes.
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SEISMOLOGY
Seismology is the scientific study of earthquakes
and the propagation of elastic waves through the
Earth or through other planet-like bodies.
The field also includes studies of earthquake
environmental effects, such as tsunamis as well as
diverse seismic sources such as volcanic, tectonic,
oceanic, atmospheric, and artificial processes .
A related field that uses geology to infer information
regarding past earthquakes is paleoseismology.
A recording of earth motion as a function of time is
called a seismogram.
6.2.1 EARTHQUAKE
Earthquake means sudden movement or
vibrations on external surface of the earth.
Usually associated with faulting or breaking of
rocks
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IT DEPENDS ON….
1 Epicenter of the earthquake.
2 Various types of vibrations and their
frequencies produced during the earthquake.
3 Mearurement of intensiy of the earthquakes
and its scale of measurement.
4 Foreshocks and aftershocks.
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1. EPICENTER OF THE EARTHQUAKE
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A point on the surface of the Earth directly above
the FOCUS of the earthquake.
The point within the Earth from which
earthquake waves originate.
2. VARIOUS TYPES OF VIBRATIONS
AND THEIR FREQUENCIES PRODUCED
DURING THE EARTHQUAKE
The two main types of waves are
1) body waves - travel through the earth's inner
layers
Two types of Body waves:
P Waves- Primary Waves
S Waves – Secondary Waves
2) surface waves- move along the surface of the
planet like ripples on water
R Waves- Rayleigh Waves
L Waves – Love Waves
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3. MEASUREMENT OF INTENSIFY OF THE
EARTHQUAKES AND ITS SCALE OF
MEASUREMENT.
Seismographs : A seismograph, also
sometimes called a seismometer, is an
instrument that measures and records the
seismic waves that move through the earth as
the result of an earthquake.
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Seismometer and seismograph
RICHTER SCALE
The Richter magnitude scale (also Richter
scale) assigns a magnitude number to quantify
the energy released by an earthquake. The
Richter scale, developed in the 1930s, is a base-10
logarithmic scale, which defines magnitude as
the logarithm of the ratio of the amplitude of the
seismic waves to an arbitrary, minor amplitude.
RICHTER SCALE
EFFECTS OF EARTHQUAKES
Richert scale Type of earthquacke Devastativs Effect
Less than 3 Very light tremor Can be detected by
seismometer only
3-5 Very Light to light
tremor
It can be experienced by
people Utensil in
kitchen vibrate and
make noise
5-6 Medium intensity
tremor
It is felt by many people
carcks appears on
building.
6-7 Medium to heavy
earthquakes
Weaker building fells
down
7- and above Devastating
earthquakes
Buliding fell down
people die or injured by
falling debris.
CAUSES OF EARTHQUAKES
Plate tectonic movements
Volcanic activity
Anthroprogenic causes
IMAGES
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6.2.2 FLOOD
A flood is an overflow of water that submerges
land that is usually dry.
The European Union (EU) Floods
Directive defines a flood as a covering by water of
land not normally covered by water.
In the sense of "flowing water", the word may
also be applied to the inflow of the tide.
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CONT…
Flooding may occur as an overflow of water from
water bodies, such as a river, lake, or ocean, in
which the water overtops or breaks levees,
resulting in some of that water escaping its usual
boundaries, or it may occur due to an
accumulation of rainwater on saturated ground
in an areal flood. While the size of a lake or other
body of water will vary with seasonal changes
in precipitation and snow melt, these changes in
size are unlikely to be considered significant
unless they flood property or drown domestic
animals.18
VARIOUS TYPES OF DISASTERS
FLOOD
6.2.3 CYCLONE
A cyclone is caused by atmospheric disturbances
around a low-pressure area and is usually
accompanied by violent storms and severe
weather conditions.
The word Cyclone is derived from a Greek word
cyclos, meaning coiling of snake. Tropical cyclone
is a deep low pressure area wherein the central
pressure falls 6 to 8 hPa (hectopascal) from the
surroundings.
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CONT…
Strong winds spiral around the centre and pick
up speeds of 62 kmph or more. These winds
rotate counter-clockwise in the Northern
Hemisphere and clockwise in the Southern
Hemisphere.
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CYCLONE OR HURRICANE
6.2.4 TSUNAMI
Tsunami, also called seismic sea wave or tidal
wave, catastrophic ocean wave, usually caused
by a submarine earthquake, an underwater or
coastal landslide, or a volcanic eruption. The
term tidal wave is frequently used for such a
wave, but it is a misnomer, for the wave has no
connection with the tides.
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TSUNAMI
TSUNAMI WAVELENGTH
• Long wavelengths (over 100 km)
• Periods longer than 1 hour
6.2.5 TORNADO
• A tornado is a violently
rotating column of air in
contact with the ground
and out from a
cumulonimbus cloud.
• Tornadoes are capable of
inflicting extreme damage.
Tornadoes can be categorized as "weak", "strong", and "violent"; with weak tornadoes often having a thin, rope-like appearance.
About 7 in 10 tornadoes are weak, with rotating wind speeds no greater than about 110 MPH.
The typical strong tornado often has a "classic" funnel-shaped cloud associated with the whirling updraft. Rotating wind speeds vary from 110 to 200 MPH.
CONT…
TORNADO
6.3 DISASTER MANAGEMENT
It is defined as an integrated approach throughappropriate, comprehensive and sustainableprinciples of development at time before, duringand after disaster so that minimum social,environmental and economical damage is done.
DISASTER MANAGEMENT CYCLE
THANK YOU…
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