hydrosphere & oceanography section 6 MCQ Questions & Answers Detailed Explanation

Answer: (d)

• Dolphin ridge and challenge ridge area in the Atlantic Ocean. Dolphin ridge is in North Atlantic Ocean while Challenge ridge is in South Atlantic Ocean.
• Cocos ridge is in the Pacific Ocean.
• South-East Indian ridge is in the Indian Ocean.
• Lomonosov ridge is an unusual underwater ridge of continental crust in the Arctic Ocean.

Answer: (c)

The circum-Pacific belt or The Ring of Fire is a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur.

In a 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. It has 452 volcanoes (more than 75% of the world’s active and dormant volcanoes).

About 90% of the world’s earthquakes and 81% of the world’s largest earthquakes occur along the Ring of Fire. The next most seismically active region (5–6% of earthquakes and 17% of the world’s largest earthquakes) is the Alpide belt, which extends from Java to the northern Atlantic Ocean via the Himalayas and southern Europe.

Answer: (d)

Answer: (c)

Answer: (d)

Answer: (d)

Spring Tides refer to either of the two tides that occur at or just after the new moon and full moon when the tide-generating force of the sun acts in the same direction as that of the moon, reinforcing it and causing the greatest rise and fall in tidal level.

The highest spring tides (equinoctial springs) occur at the equinoxes.