The Indian Ocean is the third ocean in the world, which lies between Asia, Oceania, Africa and Antarctica. Its average depth is second only to the Pacific Ocean, with an average depth of 3839.9 meters including the sea and 3872.4 meters excluding the sea. The deepest is 9074 meters.

The main seas and bays in the Indian Ocean are Red Sea, Arabian Sea, Gulf of Aden, Persian Gulf, Gulf of Oman, Bay of Bengal, Andaman Sea, Arafura Sea, Timor Sea, Gulf of Carpentaria, Bay of Great Australia, mozambique channel and so on. There are many islands in the Indian Ocean, most of which are mainland islands, such as Madagascar, Sri Lanka, andaman islands, Nicobar Islands and mentawai islands.

In addition to the mid-ridge, there are many tectonic belts in the Indian Ocean. These tectonic belts are parallel to each other and extend far away, among which the East Indian Ocean Ridge along 90 east longitude is the straightest ridge in the world.

The scope of the Eastern Hemisphere:

1, Asia, Africa, Europe and eastern Oceania: This range covers most of the Eastern Hemisphere, including the largest continents and islands in the world. Geographically, this range is bounded by east longitude 160 degrees, which divides the earth into two hemispheres: the east and the west. In this area, there are many important cities and regions, such as China, Indian, Japanese, Korean, Singaporean and Saudi Arabia.

2. Eastern North and South America: This range includes eastern South America and North America, such as Brazil, Argentina, Chile and other South American countries and the United States, Canada and other North American countries. In this area, there are many important ports and trade centers, such as new york, Los Angeles and Rio de Janeiro. These countries and regions are geographically bounded by 160 degrees west longitude and belong to the scope of the western hemisphere.

3. Eastern Russia: This range includes the Russian Far East, such as kamchatka peninsula and Sakhalin Island. Although this area is not very big, it is rich in resources and unique in culture, such as oil, natural gas, forests and so on. Geographically, this range is bounded by longitude 180 degrees and belongs to the western hemisphere.