Environmental Hazards

Presented By Ahmad HassanUniversity Of Engineering and Technology Lahore

(FSD Campus) 2014-BT-TXT-03

Contents Introduction of environmental hazardTypes of environment hazardEarthquakeTypes of earthquake weavesVolcano CausesEffects

Introduction of environmental hazardEnvironmental 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.

What is Earthquake?A sudden movement of the earth's crust caused

by the release of stress collected along faults or by volcanic activity

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.

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.

Earthquake.

VIDEO.mp4

Epicenter and Focus

Types of Earthquake WavesBody Waves

P-Waves (primary waves)S-Waves (secondary waves)

Surface Waves L – Love Waves R – Raleigh Waves

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

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

TsunamiTsunami 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

Tsunami .

VIDEO.mp4

How Measure The Earthquake Strength?1. Magnitude & 2. Intensity1. 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.

Effects Fires Building collapse

EffectsRupture Liquification

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

MagmaChamber

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

Effusive Eruptions

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

Volcano .

VIDEO (2).mp4

Volcano MonitoringSeismicityDeformationGas Output

Remote sensing techniquesThese three things are

the most important sign to an eruption.

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.

Volcano FlowHowever, 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.

Volcano FlowIt is not just explosive volcanic activity that

can be hazardous. Effusive activity is also dangerous.

Thank you