GEOGRAPHY TOPICAL QUESTIONS AND ANSWERS

Give any two natural causes of earthquakes

5/7/2023

0 Comments

Give any two natural causes of earthquakes

Isostatic adjustments
Gravitation pressure
Tectonic movement
Magma movement (volcanic activities)
Energy release in upper mantle

0 Comments

The diagram below represents the occurrence of an earthquake in the crust.

1/7/2023

0 Comments

The diagram below represents the occurrence of an earthquake in the crust.

Name the parts marked A, B, and C. (3 marks)

A – Seismic focus
B – Epicentre
C – Shock waves

0 Comments

Define the term earthquake

1/7/2023

0 Comments

Define the term earthquake. (2 marks)
An earthquake refers to a sudden and rapid movement of the earth’s crust.
OR
An earthquake refers to violent shaking of the ground due to sudden release of energy from below.

0 Comments

Apart from the movement of tectonic plates, state three other natural causes of earthquakes

30/6/2023

0 Comments

Apart from the movement of tectonic plates, state three other natural causes of earthquakes. (3 marks)

Violent movement of magma during vulcanicity.
Energy release from the mantle.
Collapsing of rocks due to gravitative pressure.
Vertical earth movements during Isostatic adjustment

0 Comments

Explain two ways in which the movement of tectonic plates causes earthquakes

30/6/2023

0 Comments

Explain two ways in which the movement of tectonic plates causes earthquakes. (4 marks)

Where two tectonic plates meet, stress builds up especially during subduction. The stress causes rocks on the edges to fracture which releases a lot of energy that triggers an earthquake.
Where two tectonic plates slide along transform boundaries, friction causes the plates to lock temporarily building stress along the edges. Eventually, rock fracture occurs which triggers vibrations that lead to earthquakes.
Along extensional boundaries, some rocks along either side of the fault may slip/slide triggering vibrations that cause earthquakes.

0 Comments

The diagram below represents the internal structure of the earth. Use it to answer question(a)

28/2/2021

1 Comment

KCSE Geography Paper 1 2002 Section B Question 9.

The diagram below represents the internal structure of the earth. Use it to answer question(a)

(a) Name the part marked U and V.

U – mohorovicic discontinuity / moho discontinuity
V – The mantle / asthenosphere

(b) Describe the deposition of:
i. The crust
ii. The core

The crust

It is made up of solid rocks.
It is divided into two layers / the sial / continental crust and sima / oceanic crust.
The sial is rich in silica and aluminium.
The sima is rich in silica and magnesium
The sima is made up of dense rocks /2.8 – 3.0 gm/cc
The sial is made up of lighter rocks / 2.7 / it floats on sima
The dial is made up of sedimentary / metamorphic rocks
The sial rocks are made of rigid / brittle rocks.

ii) The core.

It’s composed of two parts.
The main minerals of the outer core are iron and nickel
The main mineral of the inner core is iron
The inner core has higher density than outer core/ 16/17gm/cc
The outer core is melted

1 Comment

Name two scales used to measure the intensity of an earthquake

19/2/2021

0 Comments

KCSE Geography Paper 1 2006 Section A Question 4.

(a) Name two scales used to measure the intensity of an earthquake

The Rossi – forrel scale
The Mercelli scale

(b) Give three causes of earthquakes

Gravitative pressure
Collision of tectonic plates
Energy release in the mantle
Isostatic adjacent
Violent Volcanic eruptions
Nuclear explosions
Adjucent along fault lines
Building reservoirs
Magma movement within the crust

0 Comments

Give three causes of earthquakes.

11/2/2021

0 Comments

KCSE Geography Paper 1 2010 Section A Question 3.

(a) Give three causes of earthquakes.

gravitative pressure
Divergence/ convergence/collision/shearing of tectonic plate boundaries
movement of magma within the ,earth’s crust/volcanic eruption
folding/faulting
isostatic adjustment
blasting of rocks /bomb explosions/construction of large reservoirs
energy release within the mantle

(b) Name two major earthquake zones of the world.

The Circum — Pacific belt
the Tethyan/Mediterranean belt
the Great Rift Valley belt
Mid-Atlantic Ocean belt

0 Comments

What is volcanicity?

4/2/2021

1 Comment

KCSE Geography Paper 1 2013 Section B Question 8.

(a) What is volcanicity?

It is the process through which gaseous / liquid / molten rock / solid materials are forced into the earth’s crust and / ejected onto the surface.

(b) (i) Apart from a sill, name three other intrusive volcanic features.

Dykes/dikes
Laccolith/laccolites
Batholith/bathyliths
Lopolith
Phacolith/phacolite

(ii) Describe how the following features are formed:
I a sill;
II hot springs;
III a caldera.

I a sill;

Below the earth’s crust the rocks are at very high temperature and high pressure. If the pressure becomes less, the hot, solid rock material may become semi-fluid / Magma under high pressure enters crustal rocks.
The semi-fluid rock / magma forces itself into horizontal cracks/fissures.
The magma cools and solidities in horizontal cracks or bedding plane.
This horizontal sheet/layer of igneous rock is called a sill.

II hot springs;

Rainwater enters the crustal rocks through cracks / fissures.
The water reaches a zone of hot igneous rocks.
The water is (super) heated.
The super heated water changes into water vapour.
The vapour is under high pressure and so forces its way up heating the ground water.
The heated water under pressure flows out continuously/to form hot springs.

III A caldera.

Lava pouring out of a central vent forms a volcanic cone.
The vent may be sealed when lava solidifies in it.
The solidified plug block the gases and steam beneath from escaping.
There is pilling up of pressure below the plug.
The pressure leads to a violent eruption that blows off the top of the cone forming a depression.
The resulting large circular depression on the top of the (now lower) volcano is called caldera.

OR
A subsidence caldera

Lava pouring out of a central vent forms a volcanic cone.
The magma resevoir below the crust is left empty/has a void/cavity.
With time the weight of rocks of the volcano exerts pressure on the crustal rocks below.
The pressure/earth movements cause cracks to develop making the volcano unstable.
Over time the middle portion of the volcano subsides/collapses into the void forming a depression.
The resulting large circular depression on the top of the (now lower) volcano is called caldera.

OR
Outward collapsing

Volcanic eruption of ash and cinder/pyroclasts through a central vent forms a volcanic cone.
Several eruptions results to a high, steep and unstable volcano.
The weight of the upper materials exerts pressure on the ones beneath causing instability on the lower part.
The material at the base begin spreading outwards.
The top of the volcano collapses inwards forming a depression.
The resulting large circular depression on the top of the volcano is called caldera.

1 Comment

What is an earthquake?

1/2/2021

0 Comments

KCSE Geography Paper 1 2015 Section A Question 4.

(a) What is an earthquake?

It is sudden earth movement that causes vibrations within the earth’s crust.

(b) Identify the scale used to measure:
(i) the intensity of earthquakes;
(ii) the magnitude of earthquakes.

(i) The intensity of earthquakes- Mercalli scale.
(ii) The magnitude of earthquakes - The Ritcher scale.

0 Comments

Identify the two types of earthquake waves.

27/1/2021

0 Comments

KCSE Geography Paper 1 2018 Section B Question 8.

(a) (i) Identify the two types of earthquake waves.

Body waves/primary/secondary
Surface waves/love/Rayleigh

(ii) Describe the two ways through which the strength of an earthquake is measured.

The strength of an earthquake is measured by its intensity.
Intensity measures how strong and hard the earthquake shakes the ground.
It is measured on Mercalli scale.
The strength of an earthquake is measured by its magnitude.
Magnitude measures the amount of energy released by an earthquake.
It is measured on Richter scale correct method
Description
Identification of scale

0 Comments