Ten Degree Channel

Topic: Structure and Physiography of India: Himalayas, Plains, Peninsula, Coasts and Islands · NCERT: Class 11, Ch 2 "Structure and Physiography"

Meaning

The Ten Degree Channel is a stretch of sea about 150 km wide that runs along the 10°N line of latitude. It separates Little Andaman in the north from Car Nicobar in the south. So it divides the Andaman group of islands from the Nicobar group.

It matters because it marks the natural border between the two halves of the Andaman and Nicobar Islands in the Bay of Bengal. UPSC often tests it by mixing it up with the Nine Degree and Eight Degree channels of Lakshadweep.

Explanation

What a channel is

• A channel is a stretch of sea between two land masses.
• The Ten Degree Channel takes its name from the 10°N parallel, the line of latitude it runs along.
• Its two sides:
• North side: Little Andaman, the southern end of the Andaman group.

• South side: Car Nicobar, the northern end of the Nicobar group.

• Width: about 150 km. This makes it the widest gap inside the island chain.

How the island chain and its gaps formed (cause → process → result)

• Cause: the Indo-Australian plate and the south-eastern Eurasian plate keep pushing into each other [4].
• Process:
• The Indian side slides under the plate to its east.
• Sea-floor rock and mud are crumpled and pushed up into a long north–south ridge under the sea.

• This ridge continues the Arakan Yoma of Myanmar, which is the southern extension of the Purvanchal and Himalayan system.

• Result:

• The highest parts of the ridge stick out above the sea as islands.
• Where the ridge stays under water, the sea passes between the islands. These lower stretches are the channels and passages.
• The Ten Degree Channel is one such water gap. It splits the raised ridge into the Andaman group and the Nicobar group.

Its place in the chain of channels (north to south)

• Duncan Passage: between South Andaman and Little Andaman. It lies inside the Andaman group.
• Ten Degree Channel: between Little Andaman and Car Nicobar. It lies between the two groups.
• Six Degree Channel: between Great Nicobar and Sumatra (Indonesia). It lies along about 6°N. It links the Bay of Bengal and Andaman Sea with the Strait of Malacca route.
• Simple memory aid: the numbers drop as you go south: Ten Degree (10°N), then Six Degree (6°N).

Where it occurs

• India: in the Bay of Bengal, inside the Union Territory of Andaman and Nicobar Islands (capital Port Blair).
• Location of the island chain: 6°–14°N and 92°–94°E. The Ten Degree Channel cuts across it at about 10°N.
• Islands on each side:
• North: Andaman group (North, Middle and South Andaman, Little Andaman).

• South: Nicobar group (Car Nicobar, Little Nicobar, Great Nicobar).

• Wider setting: the island chain lies closer to Myanmar (north) and Indonesia (Sumatra, south) than to the Indian mainland. On the far side of the island chain lies the Andaman Sea, which also holds Barren Island, India's only active volcano, about 135 km north-east of Port Blair [3].

Don't confuse with

• Nine Degree Channel: this is in the Arabian Sea (Lakshadweep), not the Bay of Bengal. It separates the Amindivi and Cannanore islands from Minicoy.
• Eight Degree Channel: also in the Arabian Sea. It separates Minicoy (India) from the Maldives. It is an international boundary between two countries. The Ten Degree Channel lies wholly inside Indian territory.
• Duncan Passage: this lies within the Andaman group, between South Andaman and Little Andaman. The Ten Degree Channel lies between the Andaman and Nicobar groups.
• Six Degree Channel: this separates Great Nicobar from Sumatra (Indonesia), so it lies between India and another country. It is the link to the Strait of Malacca route.

Prelims Hooks

• Ten Degree Channel separates Little Andaman (north) from Car Nicobar (south). It is about 150 km wide.
• Sea: the Ten Degree Channel is in the Bay of Bengal. The Nine Degree and Eight Degree channels are in the Arabian Sea. This mix-up is a common trap.
• Order from north to south: Duncan Passage → Ten Degree Channel → Six Degree Channel.
• Match the pairs: Duncan Passage – South Andaman / Little Andaman; Ten Degree – Little Andaman / Car Nicobar; Six Degree – Great Nicobar / Sumatra.
• Origin of the islands on both sides: tectonic. They are raised tops of submarine (undersea) mountains that continue the Arakan Yoma. They are not coral atolls like Lakshadweep.

Mains Points

• The channel shows how the islands were made (GS-I):
• The Andaman and Nicobar Islands are the tops of an undersea ridge raised by plate collision [4].
• The ridge rises above the sea in some places and stays under water in others. The water gaps form channels like the Ten Degree Channel.

• The same plate boundary makes the area prone to earthquakes and tsunamis. The 26 December 2004 tsunami came from the fault here [4].

• Strategic and administrative value (GS-I/III):

• The channel splits India's eastern island chain into two groups. Both groups extend India's Exclusive Economic Zone and naval reach.
• The chain of channels, from the Ten Degree Channel south to the Six Degree Channel, leads towards the Malacca route. Great Nicobar is only about 40 nautical miles from the main East–West shipping route [2].
• So control of these waters supports India's sea security and plans such as the transhipment port at Galathea Bay [2].

Related concepts

• Andaman and Nicobar Islands
• Saddle Peak
• Lakshadweep Islands
• Nine Degree Channel
• Eight Degree Channel
• Minicoy Island

Read more

• The Islands: Andaman and Nicobar, and Lakshadweep