BORABU – MASABA DISTRICTS JOINT EVALUATION TEST– 2012

312/1
GEOGRAPHY
Paper 1
JULY/AUGUST - 2012
MARKING SCHEME

SECTION A
Answer all the questions in this section
1. (a) Give the two dates in a year during which the number of hours of darkness is equal
in both the North and South poles.
- 21st march and 23rd September (1x2=2mks)
(b) State three effects of the rotation of the earth.
- It causes the occurrence of day and night
- It lead to the raising and falling of ocean tides / high and low tides.
- It causes differences in time over different parts of the earth surface / time
difference at different longitudes.
- It causes deflection of winds and ocean currents.
- It causes difference in atmospheric pressure on the earth surface. (Any 2x1=2mks)

2. (a) The diagram below shows the hydrological cycle.

Refer to the question paper.
Name the stages in the cycle marked
A – surface run-off / overland flow
B – Evaporation
C – Condensation level. (3x1=3mks)
(b) Differentiate between a water -shed and a catchment area.
- Water shed – Is ridge line / boundary line separating drainage / river system / basic
while catchment area is an area / land from which a river or reservoir draws its
water / source of a river / rivers. A complete difference (2mks)

3. (a) What is natural vegetation

- It is the plant cover that grows naturally / wildly on the earth surface without
interference by man or his animals. (2x1=2mks)
(b) State four characteristics of the Mediterranean type of vegetation.
- Some plants have small / thick – skinned / feathery leaves / spiny leaves.
- Some plants have long roots
- Some plants have thick barks
- Some plants have large fresh bulbous roots
- Some plants have shiny / waxy leaves.
- Wood, scrub is common in very dry areas.
- Some trees are deciduous
- Some plants are ever green
- The vegetation is adopted to the long, short and dry summers.
- Some plants have flesh leaves.
- Grasses dry off during summer and germinates during winter.

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

- The Rossi – forrel scale
- The mercelii scale (Any 2x1=2mks)
(b) Give three causes of earth- quakes
- Gravitative force
- Collision of tectonic plates

©2012 Borabu-Masaba Districts Academic Committee Geography 312/1 Marking Scheme

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 - Energy release from the mantle
- Isostantic adjustment
- Violence volcanic eruption
- Nuclear explosions
- Adjustment a long fault lines
- Building water reservoirs / large dams
- Magma movement within the earth’s crust. (Any 3x1=3mks)
(c) Type of seismic wave
- P – waves / primary waves
- L – waves / Love / Rayleigh / long waves
- S - waves / secondary waves

5. (a) Causes of submergence of crusts

- Rise in sea level / Eustatic change in base level / large scale melting of ice sheets.
- Subsidence of coast lands depression of coastlands. (2x1=2mks)
(b) Characteristics of fainted lakes
- Narrow
- Deep
- Long
- Salty / alkaline
(1x1=1mk)

SECTION B
6. Map work (Homabay 1:50,000)
(a) (i) South Nyanza Country (1mk)
(ii) One centimeters represents half kilometer (2mks)
(iii) Bearing of point X from Y – 0450 10 (2mks)
Ie 044 – 046 .
0 0

(b) (i) Area of Olambwe valley National park

- Full squares = 13km2
- Incomplete squares/2 = =7.5km2
- Total area = 20.5km2 1km 2 (2mks)
(ii) Three types of natural vegetation found in the area west of Easting 50 are:
- Forests
- Scrub
- Wood lands (Any 3x1=3mks)
(c) Cross-section - ref to attached sheet (graph paper)
Awarding of marks.
Starting point 4200ft – 1mk
Ending point 3700ft 1mk
Title 1mk
Trend 1mk
Vertical scale correctly applied 1mk
5mks
River Petokin 1mk
Sugulu hill 1mk
Dry weather road 1mk
Papyrus swamp 1mk
4mks

©2012 Borabu-Masaba Districts Academic Committee Geography 312/1 Marking Scheme

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 Awarding
Starting point 4200ft – 1mk
Ending point 3700 ft 1mk
Title 1mk
Vertical scale 1mk
Trend 1mk 5mks
River Petokin 1mk
Sugulu hill 1mk
Road 1mk
Papyrus swamp 1mk 4mks
(d) Field study
(i) Two objectives
- To identify the type of manufacturing firms / enterprises present in
Homabay town.
- To find out the sources of raw materials for the processing firms
- To investigate the contribution of the presence of the processing firms in
the employment level in Homabay town.
- To find out how the marketing of the manufactured products is done.
(2x1=2mks)

(Accept any other relevant adjectives)

(ii) Two agricultural – based manufacturing firms.
- Sisal factory
- Ginnery

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 (iii) Two other economic activities and their evidence
- Trading / commerce as evidenced by the market
- Communication as evidence by the Post office
- Warehouse / storage as evidence by the maize control store.
- Transport / Distribution as evidenced by the pier and the roads.
(Any 2x1=2mks)
7. (a) (i) Soil profile is the vertical arrangement of soil particles in layers while soil catena
is the horizontal arrangement of soil on a mountain slope.
(2mks for well diffentiated )
(ii)

(Total 5mks)
(b) (i) 3 factors that influence soil formation
- Topography
- Climate
- Time
- Living organisms / biotic factors
- Nature of parent rock (Any 3x1=3mks)
(ii) Two components of soil
- Soil air, - organic miller
- Soil water, - mineral particles
(c) 4 methods that helps in soil conservation
- Crop rotation – reduces the rate of soil exhaustion as difference crops require
different minerals.
- Contour ploughing – reduces surface run-off and trap soil along contours to control
soil erosion.
- Strip cropping – reduces both wind and water erosion.
- Intercropping – provide cover over soils balances minerals in the soil.(4x2=8mks)
(d) 3 reasons why they need a route map.
- Estimate the distance of the area of study
- Avoid getting loss in the field / on the way.
- Help them identify the shortest route so as not to waste time on the way.
- To know the general nature of the terrain to the area of the study. (3x1=3mks)
(e) Tools they would carry for use.
- Jembes / pangas / spade
- Bags / paper bags / baskets (2x1=2mks)

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8. (a) (i) Differentiate between weathering and mass – wasting
- Weathering is the gradual breaking / disintegration / decay or
decomposition of solid rock while mass wasting is downward movement,
slipping, sliding of materials under influence of gravity. (2mks)
(ii) State three main weathering agents
- Heat / temperature
- Water
- Plants and animals
- Dissolved substances (3x1=3mks)
(b) (i) Explain three effects of soil creep on the earth’ surface.
- Pushes posts and fences from their original position and become inclined.
- Displacement of fine soil particles down slope leaving upper slopes bare
and exposed.
- Cause accumulation of particles at the base of the slope causing deep soils.
- Interferes with infrastructure such as roads and railways making their
maintenances expensive.
- The ends of rock outcrops may bend down slopes. (3x2=6mks)
(ii) Oxidation
- Oxygen combines with ferrous mineral components in rocks.
- Iron oxides forms on combination
- Yellow brown rust forms which easily crombles and makes the rock to
break. (3x1=3mks)
(iii) Carbanation – Calcareous rocks such as limestone and chalk easily react with rain
water, which is a weak carbonic acid, to form calcium bicarbonate .This calcium
bicarbonate is dissolved and washed in solution by running or percolating water.
(3mks)
(d) (i) Give the reason why they carried out a reconnaissance survey.
- Farmliarize with area of study
- Determine the suitability of area of study
- Identify methods of data collection and recording
- Formulate relevant policies and objectives
- Draw appropriate working schedule
- Get into contact with necessary guides
- Identify likely problems to be encountered. (3x1=3mks)
(ii) State two methods they used to record the data collected during field study.
- Tallying
- Taking photographs / video taping
- Field sketching
- Tabulation
- Mapping
- Note taking (2x1=2mks)
9. The diagram below represent undergrounds features in a limestone area use it to answer question
(9)
See question paper
(a) (i) Name the features marked
D – Stalactite
E – Stalagmite
F – Cave (3mks)
(ii) Describe how feature marked (a) is formed.
- Solution of calcium bicarbonate trickles down slowly from the roof of a
cave/ canvern.
- Solution droplet hang on the roof of the cave water evaporates and the

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 calcium carbonate gradually builds downwards over long a period of time
on the solution continues to drip from the roof. This forms a glaciated.
- Part of the solution that splashes on the floor evaporates and calcium
carbonate in it remains.
- The calcium carbonate precipitates. The precipitation of calcium carbonate
slowly build upwards to firm a stalagmite.
- Over time, the stalactite and stalagmite join to form a pillar / edumn.
(must be mentioned for one to score a maximum of 6)
(b) (i) What is an artesian depression? It is a sancer shaped depresion consisting of a layer
of permeable rock lying between two layers of impermeable rocks, with part of the
permeable rock exposed to the surface along the edge of the basin.
(ii) Explain three factors which influence the formation of features in limestone areas.
- The surface rock must be a thick limestone to allow solubility by rain
water.
- The rock should be hard, well jointed to allow water to penetrate through
the lines of weakness / rock joints.
- The climate should be humus to facilitate chemical reaction / weathering/
carbonation.
- The water table should be far below the surface to allow for the formation
of the features. (3x2=6mks)
(c) You are intend to carry out a field study in an area ended by water.
(i) Give three reasons why you would need working schedule.
- To ensure all planned activities are carried out.
- To save on time programmed for the field study
- To ensure well coordinated field study among students
- To avoid being distructed to unintended activities.
- To ensure the objectives of the field study are achieved. (3x1=3mks)
(ii) Name two erosional features you are likely to identify during the study
- Exposed rocks / inselbergs / tors
- Ridges / clintl
- Gullies / wadis / gnkes / dry river valleys
- Earth pillars (Any 2x1=2mks)
(iii) State three recommendation that you would make from your study to assist the
local community to rehabilitate the eroded areas.
- Building of gabions
- Constructing terraces
- Planting trees / planting cover crops
- Adapting farming methods that allow conservation of soil / contour
ploughing / stripe cropping (Any 3x1=3mks)

10. (a) (i) What is an ice sheet?

- It is a continuous mass of ice covering a large area surface (2mks)
(ii) Give two reasons why there are no ice sheets in Kenya.
- Kenya is located along tropical areas and experienced high temperatures
therefore ice sheets cannot form.
- Most parts of Kenya have steep gradient / are highlands thus discouraging
accumilation of ice.
- Kenya is found at low latitudes and experiences high temperatures.
(2x1=2mks)
(iii) Explain the factors which influence the movement of ice sheet from the place of
accumulation
- Gradient of the land – ice moves faster when the slope is steeper than
gentle gradient.

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 - Temperature / seasonal changes – Higher temperatures results in to
Thawing leading to faster movement of ice.
- Nature of the surface When the surface on which ice is moving is rough It
causes friction lowering the speed of the movement of ice. Smooth / even
surfaces enlarge faster ice movement.
- Size / thickness of glacier .Large masses of ice exerts pressure which lead
to melting of ice underneath. This increases the speed of ice movement.
(Any 3x2=6mks)
F–3
EX 3 6mks
(b) Describe how an arete is formed
- Two adjacent cracks / hollows exist on mountain side.
- The two hollow / cracks are filled with ice.
- The ice erodes the \sides through plucking and deepens the hallow through
abrasion.
- Through erosion, The back walls of the hollows slowly recede.
- Eventually the hollows (acquires) are separated by a knife –edged ridge of a rock.
- The feature is called an arête
N/B The last point must be mention for one to score a maximum of 4.(4x1=4mks)
(c) Name the types of moraines marked S,T and V. see the question on the question paper
S – medial
T –Lateral
V – Terminal
(iii) Explain four effects of glaciations in lowland area.
- Glacial till provides fertile soils for arable farming
- Ice sheet, in their scouring effects lower land surface and depict to expose
minerals which becomes easy to extract.
- Out wash plains comprise of land, and gravel which are used as materials
for building and construction.
- Lakes formed through glaciations can be exploited for various economic
uses such as fishing transportation or as tourist attraction.
- Glaciated features are tourists attractions which earn foreign exchange.
- Glaciated lowlands are generally flat due to erosional and deposition an
are for ideal for construction of building and communication lines.
(Any 4x2=8mks)

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