Assertion (A): Volcanoes do not create fertile land in Iceland.Reason (R): The weather is too cold to weather the lava flows.
Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not a correct explanation of A
A is true but R is false
A is false but R is true
Which of the following is NOT true of sea-floor spreading?
Oceanic ridge is formed
It is basically volcanic
A depression called oceanic trench is formed
The boundaries that experience this process are 'constructive'
Which of the following statements is false about magma?
It is a layer of molten rock
Its temperature is about 2000oC
It is the same as the mantle
It rises to the Earth's surface during an eruption.
Deep focus earthquakes are associated with which type of zones?
Collision zone
Subduction zone
Constructive margins
Conservative margins
Which of the following causes the movement of tectonic plates?
Conduction current
Convection current
Radiation
Tsunami
Which of the following is NOT a trigger for tsunami?
Undersea earthquakes
Landslides
The eruption of an oceanic volcano
Wind
The scale used to measure the strength of an earthquake.
Richter scale
Mercalli scale
Beufort scale
Davis scale
