(a) State two conditions that favour the formation of fog. (2 marks)

-Air must have abundant moisture.

-Cloudness/clear sky to facilitate terrestrial radiation.

-The air must be calm for a long time

. -Air must be cooled below dew point. 2 x 1 = (2 marks)

(b) Name three other forms of precipitation that are common in Kenya (other than fog). (3 marks)

-rain

-hail

-dew

-mist 3 x 1 (3 marks)

(a) State two reasons why the interior of the earth is still very hot. (2 marks)

-The overlying layers of rock exert a lot of pressure thus generating heat.

-During the formation the interior cooled very slowly and still retains the original heat.

-Radioactivity within the core due to nuclear fusion results in generation of heat. 2 x 1 = (2 marks)

(b) Give the two layers of the earth’s crust. (2 marks)

-Sial/continental.

-Sima/oceanic 2 x 1 = (2 marks)

(a) Name two types of river deltas. (2 marks)

-Arcuate

-Birds foot

-Estuarine. -Inland. 2 x 1= (2 marks)

(b) State four conditions that are necessary for formation of a delta. (4 marks)

-Large quantities of sediments/silt carried by the river.

-Low velocity/speed of the river at the mouth/gentle slope at the river mouth.

-Weak sea waves/weak tidal currents at the coast/ calm sea at the river mouth.

-Shallow continental shelf around the river mouth/shore.

-Faster rate of deposition than the rate of removal of silt at the river mouth.

-Absence of obstacles/filters along the river course. 4 x 1 = (4 marks)

(a) A part from equatorial rainforest name two other

types of forests that are found in Africa.
(2 marks)

-Montane/mountain forest.

-Planted/man-made forests.

-Mangrove forests.

-Savanna woodland. 2 x 1 = (2 marks)

(b) State three characteristics of equatorial rainforest. (3 marks)

-Trees take long time to mature.

-Trees grow in mixed stand/different tree species grow together.

-Trees have buttress roots.

-Trees form three distinct canopies. /trees grow in three different layers of heights.

-The trees are mainly hardwoods.

-There is little or no undergrowth.

-Trees have tall straight trunks.

-Creepers/lianas twine around trees.
-Most of the trees have broad leaves.

-Most trees are evergreen/forest is ever green 3 x 1 = (3 marks)

(a) Differentiate between mass wasting and weathering. (2 marks)

-Mass wasting is the movement of rock materials down the slope due to gravity

while weathering is the chemical decomposition or physical breakdown of crustal rocks in situ. 1 x 2 = (2 marks)

(b) Give three main agents of weathering. (3 marks)

-Air

-Water

-Ice

-Biological organisms 3 x 1 = (3 marks)

Study the map of Kitale (1:50,000) sheet 75/3 provided an answer the following questions.

(a)i) Give the six figure grid reference of the air photo principal point no 92/KE/13 01 (2 marks)

Grid reference is 238127 1 x 2= (2 marks)

ii) What is the approximate height of the dam in grid square 2429? (2 marks)

Approximate height is 1940m 1 x 2= (2 marks)

b)i) Calculate the area of Kapolet forest in square kilometres. Show your working. (2 marks)

ii) A part from the forest give three other types of natural vegetation found in the area covered by the map. (3 marks)

-scrub

-scattered trees

-woodland

-papyrus/papyrus swamp vegetation

-riverine trees. 1 x 3 = (3 marks)

c)i) Identify three methods that have been used to represent relief in the area covered by the map. (3 marks)

-Contours

-Form lines

-Trigonometrical stations -Spot heights. 3 x 1 = (3 marks)

ii) Citing evidence form the map give three economic activities carried out in the area covered by the map. (3 marks)

Transportation

- all types of roads/motorable tracks/foot paths/railway stations.

Farming

- Saiwa farm/dip at grid square 2826

Fishing

- Fishing hut (grid square 4225)

Trade

- Roads/motorable tracks/footpaths/municipality (boundary)/township

Forestry

- Forest nursery at grid square 2512 1 x 3 = (3 marks)

d(i) Describe the relief of the area covered by the map. (3 marks)

-The area has some hills i.e Rogur Hill at grid square 4624.

-There are some steep slopes to the west of Kapolet and South of Kiptaber forests.

-Most of the area to the South and North West is gently sloping/undulating.

-The area has been dissected by many river valleys.

-The area slopes downwards from the North east –Westwards.
- The highest point is the peak of Rogur Hill at 2362m/

-The lowest contour is at 1800m (grid square 3011) 1 x 3 = (3 marks)

ii) Give three features that show that the area covered by the map has a wet climate. (3 marks)

-Permanent rivers i.e Kapolat/Neigameget.

-Forests

-Papyrus swamps i.e Sitatunga swamp.

-Plantation estates i.e at Sinyerere 3 x 1 = (3 marks)

(e) Draw a rectangle measuring 14 cm by 10 cm to represent the area

enclosed by eastings 35 and 42 and northings 12 and 17. (1 mark)

On it mark and name the following Murram road C 638 (1 mark)

River Noigameget (1 mark)

Bridge

a) Give three natural causes of earthquakes. (3 marks)

-Movement of magma through crustal rocks/vulcanicity.

-Isostatic adjustment.

-Tectonic movement/faulting/folding.

-Convectional currents in the mantle.

-Gravitative pressure.

-Energy release in the mantle. 3 x 1 = (3 marks)

b)i) Name two types of seismic waves. (3 marks)
-Primary/P waves.

-Surface longitudinal waves/L waves

-Secondary waves/S waves. 2 x 1 = (2 marks)

ii) What is vulcanicity? (2 marks)

The process through which liquid or gaseous materials are forced out

of the interior into the earth’s crust or onto the earth’s surface. 1 x 2 = (2 marks)

c) State two causes of vulcanicity. (2 marks)

-High pressure in the interior of the earth which is released by earth movements.

-High temperatures which cause solid rock material change into molten state/magma.

-Faulting which creates cracks and fissures in the rocks through which magma escapes. 2 x 1 = (2marks)

d) Giving examples, describe how each of the following is formed.

i) A lava plateau. (4 marks)

-Formed when basic or ultra-basic lava reaches the earth’s surface through single or multiple vents /fissures.

-The lava spreads over a large area because it has low viscosity before cooling.

-The lava cools rapidly forming an extensive table like platform known as a lava plateau.

-The plateau may form due to a series of eruptions which results in thick layers of lava.

Example of lava plateau is:

-Yatta plateau

-Laikipia plateau Description maximum 3

-Uasin Gishu plateau Example 1 4

-North West Kenya plateau

-Maralal-stony Athi plateau. N/B Diagram not a must.

ii) Caldera (4 marks)

Can form in either of the following ways. Outward collapsing

-Volcanic eruption of pyroclasts /cinder and ash through a central vent forms a volcanic cone.

-Several subsequent eruption result in the formation of a high steep sided and unstable volcano.

-The weight of the upper part of the volcano exerts pressure on the lower part making it unstable.

-The material at the base begin to spread outwards.

-The top of the volcano collapses inwards forming a depression.

-*The resultant large circular depression in the top of the volcano is the caldera.
OR -Lava pouring out of a central vent forms a volcanic core.

-The magma reservoir below the crust is left partly empty/develops a void/ cavity.

-Over time the weight of the rocks of the volcano exerts pressure on the crustal rocks below.

-The pressure/earth movements cause cracks to develop making the volcano unstable.

-Eventually the middle portion of the volcano collapses into the void forming a depression.

-*The large depression on top of the now lower volcano is called a caldera

. Example Menengai, Ngorongoro, Lake Shala Description maximum 3

Example -1 max (4 marks) Or By violent explosion.

- A volcanic eruption occurs forming a volcano.

- The magma in the vent cools and solidifies sealing the vent.

- Over time the gases and the steam beneath the volcano in the interior are heated by molten lava.

- They expand increasing pressure below the volcano.

- When the pressure is too high it overcomes the resistance of the volcanos rocks

. -This causes the top of the volcano to explode violently blowing off the top/head.

-*This results in the formation of a new and large depression called explosion caldera.

Examples:Sabino,Nyamlagira,Nyiragongo,Longonot,Suswa. Description max 3 mrks Example 1 mark 4 marks
NB*Must be mentioned to score maximum 3 marks in description

e) Your class is required to carry out a field study on igneous rocks around your school.

i) Give three sources of information you are likely to refer to before the field study. (3 marks)

-Relevant reference books.

-Magazines/journals.

-The internet/electronic media.

-Geological maps/National Atlas.

-Geologists/experts. -Photographs/video/CD/DVD

-Geography notes

ii) State three activities you are likely to carry out during the field study. (3 marks)

-Observing rocks

-Collecting samples

-Labelling samples

-Digging/breaking the rocks

-Sketching diagrams/maps.

-Filling in tables/tabulation

-Identifying rocks. 3 x 1 = (3 marks)

iii) State two problems you are likely to encounter during the field study. (2 marks)

-Heavy rain.

-Attack by wild animals/insects/snake bites. -

Shortage of time.

-The area was too large to cover. -Walking for long distances/getting tired.

-Inaccessibility of some areas. 2 x 1= (2 marks)

a)i) Differentiate between aridity and desertification. (2 marks)

Aridity refers to the state of land being deficient in moisture leading to scarcity of

vegetation or lack of it while desertification is the steady encroachment of desert like

conditions into formerly productive agricultural land. 1 x 2 = (2 marks)

ii) Name two types of deserts. (2 marks)

-Rocky desert/erg/koum

-Stony desert/reg/serir

-Sandy desert/Hamada (2x1=2 marks)

b)i) Explain three reasons why wind is the main/dominant agent of erosion in hot deserts.(6mks)

-Presence of loose/dry sand which is easily carried by wind.

-Desert winds are very strong hence easily erode and carry away a lot of materials.

-Absence of vegetation cover to break wind speed/force which exposes the desert surface to easy erosion.

-Extensive flat terrain which allows wind to gain strength/speed which gives power to erode. 3 x 2= (6 marks)

ii) State four factors that influence wind deposition in the desert. (4 marks)

-Nature of the desert surface.

-Presence of obstacles.

-Strength and direction of wind.

-Variation in the weather conditions.

-Amount of load carried by wind. 4 x 1 = (4 marks)

c)i) Give three processes of wind erosion in deserts. (3 marks)

-Abrasion

-Deflation

-Attrition 3 x 1 = (3 marks)

ii) Name three features that form as a result of water action in deserts. (3 marks)

-Insellbergs -Buttes and mesas

-Gorges

-Wadis

-Alluvial fans

-Bagadas/bahadas
-Inland drainage basins/playas

-Pediments

-Pediplains 3 x 1 = (3 marks)

d) Your class is required to carry out a field study on desert features resulting from wind action.

i) State three reasons why you may need to sample parts of the desert. (3 marks)

-To save on time.

-To reduce the cost of the field study

-To focus on relevant areas.

-To conduct a detailed study of the areas selected.

-To reduce bias in data collection.

-The whole desert is too big to cover it adequately. (3x1=3 marks)

ii) List two sampling techniques you are likely to use. (2 marks)

-Random

-Systematic

-Stratified. 2 x 1 = (2 marks)

a)i) Name the features marked M, N and O. (3 marks)

M - Blow hole (1 mark)

N - Cave (1 mark)

O - Cliff (1 mark)

ii) Name three types of submerged coasts. (3 marks)

-Fiord/fjords/fjard coasts

-Ria coasts

-Dalmation/longitudinal coasts. -Estuarine coasts. 3 x 1= (3 marks)

b)i) State five conditions that favour the growth of coral. (5 marks)

-The water should be warm about 200-300C

-The water should be shallow/depth of upto 60 m to allow penetration of sunlight.

-The water should be clear and free from silt/mud.

-Well oxygenated water.

-The water should be saline/salty

-There should be plentiful supply of plankton. 5 x 1 = (5 marks)

ii) Explain three ways in which coral contributes to the growth of Kenyan’s economy. (6 marks)

-Coral forms beautiful features which attract tourists who bring foreign exchange.

-Coral reefs provide a habitat for fish to breed which promotes the fishing industry/which is a source of food.

-Coral leads to formation of limestone which is used as a raw material for manufacture of cement.

-Coral rocks provide building material which is used in the building and construction industry.

-Some coral stones are extracted and sold as ornaments which earns income. 3 x 2= (6 marks)