THE ISLANDS

           AN OVERVIEW :

         Andaman and Nicobar groups of islands are situated in the Bay of Bengal, mid way between peninsular India and Mayanmar, spreading like a broken necklace in the North-south direction. These islands are located between 6º 45' and 13º 41' North latitudes, and 92º 12' and 93º 57' East longitude. There are in all 349 islands which can be distinguished into two groups geographically. Islands located north of 10º N latitude are known as Andaman group of Islands while islands located south of 10º N latitude are called Nicobar group of islands. There are 325 islands in Andaman group while Nicobar group has 24 islands. Total geographic area of Andaman & Nicobar Islands is 8249 sq.km. of which Andaman group of islands cover 6408 sq.km. while Nicobar group cover 1841 sq.km. Out of total 556 islands only 37 islands are inhabited by human beings – 24 in Andaman group and 13 in Nicobar group of islands.

      GEOGRAPHY AND GEOLOGY :

These islands are the summits of a submarine mountain range lying on the great tectonic suture zone extending from the eastern Himalayas along the Mayanmar border to the Arakan and finally Sumatra and Lesser Sundas. The northern most part of these islands is isolated from cape Negrais in Southern Mayanmar by the North Preparis channel and the southern most part is also separated from the Acheen Head  of  Western  Sumatra  by   the   Great channel. 

There are two more deep channels – (i) the ten degree channel which isolates Andaman islands from Nicobar islands and  (ii) the Sombero channel which isolates Great Nicobar from Nicobars and the Nancowries group.

  The physiography of these islands is characterised by undulating topography and intervening valleys. There are, however, some flat islands like Car Nicobar and Trinket. There is no major perennial fresh water river in these islands except Kalpong in North Andaman, Alexendra, Dagmar and Galathea river in Great Nicobar. There are several rainfed streams which dry up during summer. The coastal line of these islands is wavy with large number of bays, lagoons and serpentine creeks, and extends to about 1962 km. At several places tidal creeks penetrate far inside the land and form outlets for fresh water streams.

  Geologically, these islands belong to a geosynclinal basin. The rocks are highly folded due to frequent tectonic movements in past. The geological formations represent a period of sedimentation from cretaceous to sub-recent period. The surface deposits of gravel beds and raised soil covers are of recent origin i.e., less than 10,000 years. The present configuration of these islands took shape only about 26 million years ago.

 Two islands of volcanic origin are found here-the Narcondum and the Barren islands. The former is now apparently extinct while the latter is still active.

     SOIL :

Soil cover is rather thin, varying from 2m to 5m. It is mostly alluvial on hill tops while diluvial in ridges and valleys. The coastal flats have an admixture of sand, silty clay and diluvial material with fine fragments of coral lime. The soil is, in general, mild to moderately acidic with high humus on top.

CLIMATE :

These islands have a tropical climate which  is  warm,  moist  and  equable. The temperature  ranges  from 18º C to 34ºC. The proximity of the sea and the abundant rainfall prevent extremes of heat. An average of 3000 mm rainfall per year is received from south west and north east monsoons which extend over a period of eight months. The extent of rainfall may vary with island. The humidity is high varying from 66 to 85%. In normal conditions the wind speed is fairly constant (5 knots per hour) but during cyclonic weather it may go as high as 120 to 130 knots per hour.

         DEMOGRAPHY :

        The population of these islands during last three census is shown in the following table

 Population of Andaman and Nicobar Islands :

   Figures in above Table shows that the population is growing at a rapid pace. This increase is mainly due to the immigration of people from mainland. The density of population is about 34 persons per sq.km. Population is mainly dominated by settlers from mainland. Tribal population constitute only 9.54% of total population. Main occupations of people include agriculture, animal husbandry, fishing, forestry and plantations, construction, transport, trade and commerce.