This document discusses environmental hazards such as earthquakes and volcanoes. It defines earthquakes as sudden movements caused by faults or volcanic activity. Earthquake waves are categorized into body waves (P and S waves) and surface waves (Love and Rayleigh waves). Volcanoes form when magma rises from the earth's crust and erupts. Volcanic eruptions can be effusive or explosive depending on gas and viscosity levels. Monitoring seismic activity, ground deformation, and gas outputs provides signs of impending volcanic eruptions. Volcanic flows also pose hazards, though spraying water can help slow them.

1. Presented By Ahmad Hassan
University Of Engineering and Technology Lahore
(FSD Campus)
2014-BT-TXT-03

2. Contents
Introduction of environmental hazard
Types of environment hazard
Earthquake
Types of earthquake weaves
Volcano
Causes
Effects

3. Introduction of environmental
hazard
 Environmental hazards is the state of events
which greatly effects the surrounding and
people’s health.
 This situation cause pollution and natural such
as storm, earthquake and volcano.

4. What is Earthquake?
 A sudden movement of the earth's crust caused
by the release of stress collected along faults or
by volcanic activity

5. How Earthquake Happens?
 It caused by a sudden slip on a FAULT.
 Stresses in the earth's
outer layer push sides of
fault together.
 Stress builds up & rocks
slips suddenly, releasing
energy in waves that travel
through the earth's CRUST
& cause the shaking that we
Feel during an earthquake.

6.  Fault- earthquake
 A fault is a fracture along which the blocks of outermost
major layer of the earth, on either side have moved relative
to one another parallel to the fracture. Faults are classified
to Strike-slip and Dip-slip faults (normal, reverse and
thrust).
 What is the crust?
 The outermost major layer of the earth is called CRUST and
ranging from about 10 to 65 km in thickness worldwide.
The uppermost 25 km of crust is brittle enough to produce
earthquakes.

7. Earthquake
.

8. Epicenter and Focus

9. Types of Earthquake Waves
 Body Waves
 P-Waves (primary waves)
 S-Waves (secondary waves)
 Surface Waves
 L – Love Waves
 R – Raleigh Waves

10. Body Waves: P and S waves
 Body waves
 P or primary waves
 fastest waves
 travel through solids,
liquids, or gases
 compression wave,
material movement in
the same direction as
wave movement
 S or secondary waves
 slower than P waves
 travel through solids
only
 shear waves - move
material perpendicular
to wave movement

11. Surface Waves: R and L waves
 Surface Waves
 Travel just length of the ground’s surface
 Slower than body waves; rolling and side-to-side movement
 Especially damaging to buildings

12. Tsunami
 Tsunami is a series waves caused by earthquakes or
volcanic eruptions under the sea.
 Out in the depths of the ocean, tsunami waves do not
dramatically increase in height. But as the waves travel
inland, they build up to higher and higher heights as the
depth of the ocean decreases. The speed of tsunami
waves depends on ocean depth rather than the distance
from the source of the wave. Tsunami waves may travel
as fast as jet planes over deep waters, only slowing down
when reaching shallow water

13. Tsunami
.

14. How Measure The Earthquake Strength?
1. Magnitude & 2. Intensity
1. Magnitude:
 A measure of actual physical energy release at its source as
estimated from instrumental observations.
2. Intensity:
 A measure of the felt effects of an earthquake rather than the
strength of the earthquake itself.

15. Effects
 Fires
 Building collapse

16. Effects
 Rupture
 Liquification

17. Volcanoes
 A volcano is a vent that
connects molten rock
(magma) from in the
Earth’s crust to the Earth's
surface.
 The volcano includes the
surrounding cone of
erupted material
Vent
Magma
Chamber

18. How and why do volcanoes erupt?
 Hot, molten rock (magma) is floating and will rise up
through the crust to erupt on the surface.
 When magma reaches the surface it depends on how easily
it flows and the amount of gas (H2, CO2, SO2) it has in it as
to how it erupts.
 Large amounts of gas and a high viscosity (sticky) magma
will form an explosive eruption!
 Small amounts of gas and low viscosity magma will form an
effusive eruption

19. Effusive eruptions are
characterized by outpourings
of lava on to the ground.

20. Volcano
.

21. Volcano Monitoring
 Seismicity
 Deformation
 Gas Output
 Remote sensing techniques
 These three things are
the most important sign
to an eruption.

22. What is volcano monitoring?
 As magma moves through the Earth’s crust it can alter it’s
environment producing sign’s on the surface, these signs
are called “precursors” to an eruption.
 Precursors include
• Increased earthquakes in the area means increased
seismicity
• Swelling and cracking of the ground means deformation
• Change in the amount of chemistry of the gas coming out
of the volcano
• Change in the groundwater levels and chemistry.

23. Volcano Flow
 However, the potential damage was reduced by
spraying seawater onto the advancing volcano flows.
 This caused them to slow and stop away from the
undamaged part of the town.

24. Volcano Flow
 It is not just explosive volcanic activity that can
be hazardous. Effusive activity is also
dangerous.