<< Chapter < Page Chapter >> Page >

South Africa is situated in the centre of a ground-plate; therefore we may not necessarily experience very serious earthquakes. But the stirrings in the mantle of the earth’s crust are noticeable in South Africa, as we have experienced in 1969 when an earthquake in the Boland caused much damage in Ceres.

In the next learning unit the map will show that earthquakes and volcanoes occur at the same place s.

(See figure 8)

Activity 2:

To indicate on a map of the world in which areas earthquakes occur

[lo 2.1, 2.2]

2. The effect (consequences) of earthquakes on the lives of people and socio-economic activities

Read the magazine article that follows.

You are simply strolling down the street in the city or town where you live. Suddenly the ground around you starts to buckle and form waves like those that form in a dam into which a stone is hurled.

An awful droning, almost like a lamentation, rises from the earth. Around you buildings collapse like houses built of cards and the street in front of you is bursting open as if made of strips of soft, torn cardboard.

Railway girders bend and tear, bridges collapse, dam walls break. People and cars tumble into the enormous gaping cracks in the earth. The cracks close up again and everything disappears forever. Everywhere bricks, concrete blocks, beams and pillars fall down on people who scramble left and right for a place of shelter that cannot be found.

Fires break out because electric cables and gas pipes are broken. Water rushes from burst pipes. Windowpanes lie shivered into razor-sharp splinters among the rubble, adding to the horror. A most dreadful natural disaster. Horror as humankind has known it since the earliest times. Earthquake!

Huisgenoot, Jongspan , 21 May 1987.

Such an earthquake is rated as a very serious disaster, but all earthquakes fortunately are not equally severe. There may be a tremor of the earth’s crust every thirty minutes, but only about 500 of them are actually felt in any year. Fortunately those that do great damage and claim thousands of lives are few and far between.

Trace the world map from figure 8 and indicate only the areas where earthquakes occur. Then colour it in red.

Activity 3:

To discuss the consequences of earthquakes

[lo 2.1, 2.2]

1. Read the magazine article attentively. Form groups for discussing the effects of earthquakes on:

a) People

b) Nature

2. Collect photographs, pictures and newspapers or magazine cuttings dealing with earthquakes. Bring it along to the class for a discussion session and use it to supplement the information in your notes.

3. Read the following paragraph dealing with Tsunamis and try to find pictures and additional information dealing with this natural phenomenon.

Tsunami – another result of earthquakes!

When rock on the ocean floor shifts unexpectedly, the overlying seawater is also affected and a gulf that can move at 800 km per hour develops. When the gulf reaches the shallower bays of coastal areas it is dammed up higher. It can reach heights of between 30 and 60 metres and can cause serious destruction by flooding and destroying harbours and towns along the coast.

Questions & Answers

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Geography grade 7. OpenStax CNX. Sep 09, 2009 Download for free at http://cnx.org/content/col11021/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Geography grade 7' conversation and receive update notifications?

Ask