Andaman Sea

The eastern margin of the Andaman Sea falls sharply from shelf to continental slope, while broad shelves and submerged mountains create several distinct marine zones. The Andaman and Nicobar arc controls water exchange with the Bay of Bengal through straits of different widths and depths. Monsoon currents carry nutrients and sediment along the coast, supporting fisheries and coastal settlement.

The Burma plate meets the Indo-Australian plate beneath these waters. Great earthquakes in 1797 and 1833 showed the scale of past movement, and Barren Island rises from the same subduction system. Its sparse eruptions and surrounding reefs made the island a visible hazard and landmark for sailors. Deep channels offered passage, but shallows, storm waves and volcanic slopes demanded caution.

Islands and mainland coasts offered shelter to fishing boats and traders moving between India, Burma and the Malay world. Local pilots read tides, monsoon shifts and the position of reefs. The seascape was therefore shaped both by gradual deposition along the shelves and by sudden uplift beneath the islands, producing a route network that changed over human memory as well as geological time.