Question 1
- Define the term Tsunami.
- State three effects of earthquakes on the earth’s crust.
Answer
- - Tsunami is a large scale sea wave caused by an earthquake on the sea floor.
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- Rocks of the earth crust are displaced laterally due to earthquakes. Can lead to faulting of crystal rocks.
- Earthquakes causes raising/uplift and lowering/subsidence of the land.
- Causes the lowering or rising of some parts of the sea floor.
Question 2
- What is climatic change
- Outline four human activities that contribute to climatic change
Answer
- - This is the gradual changes in climate due to variations that occur in the atmospheric conditions
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- Construction of reservoirs/human made lakes – modification of the local climates
- Deforestation leads to audacity.
- Industrialization – emission of CFC (chloroform carbon) depletes the ozone layer causing global warming.
- Urbanization – high temperatures in urban centres
Question 3
- Define the term river capture
- State three conditions necessary for river capture to take place.
Answer
- - The diversion of the headwaters of a less powerful river into a more powerful river in an adjacent valley.
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- The pirate river and the less powerful river must be flowing in adjacent valleys.
- The pirate stream should have a wider and deeper valley than the less powerful river.
- The pirate river must have greater head ward and vertical erosion.
Question 4
The diagram below illustrates a composite volcano. Use it to answer question (a)
Name the features marked A, B, and C.
- Name two examples of the above feature in Kenya.
Answer
-
A - Crater
-
- Mt. Kenya
- Mt. Elgon
- Mt. Longonot
B - Ash/cinder layer
C - Parasitic cone
Question 5
- Name two forces responsible for the geoid shape of the earth
- Give three reasons why the interior of the earth is very hot
Answer
-
- Centripetal
- Centrifugal -
- The original heat is still retained
- Radioactivity
- The overlying materials exert pressure that generates heat.