Sumatra

Sumatra is located in both hemispheres and is divided by the equator into almost equal parts. The area of ​​the island is about 473 thousand km².

The island is stretched from the northwest to the southeast by about 1.8 thousand km, reaching a width of 435 km. Sumatra is the most western of the main islands of the Indonesian archipelago.

The Strait of Malacca divides Malacca and Sumatra. The Sunda Strait separates Sumatra from Java .

The coastline is indented weakly, coral reefs are found near the coast.

The largest lake in Sumatra is Toba .

Sumatra is characterized by a high magnitude of earthquakes (up to 7-8).

The relief of Sumatra on the southwestern coast of the island is mountainous - the Aceh and Batak plateaus , the Barisan ridge. The ridge is divided by the fault zone into two parallel chains, which are composed of Paleozoic rocks - limestone , quartzite , crystalline schists , with outcrops of granite intrusions. There are many volcanoes on the island, 12 of which are active.

The highest point on the island of Sumatra - the active volcano Kerinci , or Indrapura (3805 m) is located in the central part of the Barisan mountain range. Other major volcanoes include Dempo (3159 m), Marapi (2891 m).

The northeastern part of the island is represented by a lowland plain composed of river sediments.

The climate in Sumatra is equatorial , hot and humid. Monthly average temperatures range from 25 to 27 ° C. From December to March, northeast winds prevail, from July to September - southwest. Precipitation from 1000 mm per year in the eastern regions of the island, to 4000 mm in the western regions; in mountainous areas - up to 6000 mm.

Sumatra is rich in rivers. The main ones: Rokan, Kampar, Inderaghiri, Hari , Musi. The largest of them flow from west to east.

The largest lake in Sumatra is Lake Toba , located in the caldera of an ancient volcano and is the largest and deepest lake in Southeast Asia. The length of the lake is 100 km, width - 40 km, area - 1145 km². The depth of the lake is about 450 m. In the center of the lake is Samosir island, with an area of ​​530 km².

On the island of Samosira there is another lake - Sidohoni. At the northern end of the lake is a 120-meter Sipiso Piso waterfall.

The surface of Lake Toba is located at an altitude of 906 m above sea level. The water level in the lake is gradually decreasing.

Flora

More than 30% of the territory of Sumatra is covered by rainforest . In the moist equatorial forests of the island up to heights of 1500 m, ficuses , various palm trees , giant bamboo , tree-like ferns , lianas predominate. In the mountains at heights of more than 1,500 m, evergreen oaks and laurels, broad-leaved deciduous species, maple, chestnut, and coniferous trees predominate.

Above 3000 m, undersized shrubs and grasses grow. In the intermontane plains are areas of the savannah , in which Alang-Alang is common. Mangroves are common on the northeast coast.

Fauna

The wildlife of Sumatra is diverse. Sumatra is home to: 196 species of mammals, 194 species of reptiles, 62 species of amphibians, 272 species of fish and 456 species of birds, of which 9 species of mammals, 19 species of birds and 30 species of fish are endemic .

Sumatran rhino , Indian elephant , buffalo , black tapir , Sumatran tiger , Malay bear , pig -tailed macaque , orangutan , gibbon , siamang , woolly-winged , striped pig, Bornean smoky leopard , island wyverra , various species of squirrels are found from the animal kingdom. Of the reptiles - large snakes, "flying dragon", gavialovy crocodile . The world of birds and insects is no less diverse. Many of the species of flora and fauna are endemic to the island.

About 73 thousand years ago, a gigantic explosion of the Toba volcano occurred on the island of Sumatra ^[2] . As a result, a crater with a diameter of about 100 km was formed at the site of the explosion, and 800 cubic kilometers of dust and ash fell into the atmosphere. This event, according to scientists, had dramatic consequences for the human population ( the bottleneck effect , as a result of which the population of the Earth decreased to 2 thousand people ^{[3] [4]} ), as it provoked a 1800-year ice age ^[5] .

Two teeth of modern people from the cave Lida Ajer, found by the anthropologist Eugene Dubois, date from 63,000 to 73,000 years ago ^[6] .

The eastern and southern regions of Sumatra and the adjacent small islands, where the formation of the Malay nationality took place, historians have traditionally attributed to areas of the earliest political genesis .

The ancient Sumatran states were guided by sea routes, which, skirting Sumatra from the north, went along the Malacca Strait , along the eastern coast of Sumatra, then around South Malaya they turned north to the Indochina peninsula and the Chinese coast, or went to Java and through the Java Sea - to East Indonesia, to the Spice Islands. River and transshipment land routes through Northern Malaya to the Gulf of Thailand were also important for the North Sumatran regions.

In the basins of the Sumatran rivers Batang and Musi, which connected the Viutriostrov region with foreign trade routes, initially there were conditions for rice growing and rich forest resources. With these lands (the Jambi-Palembang region), the sources mentioned by Chinese sources in the middle of the 3rd century BC are identified. e. the kingdom of Gain (Dyain) is one of the centers of intermediary trade, which maintained ties with both China and Indian ports and existed until the VI century BC. e.

Chinese source of the 3rd century AD e. “Qian Han Shu” also mentions the kingdom of Pizong (Pisang), which lay on the sea route from India to China and occupied the Rio-Ling Islands off the southeast coast of Sumatra. The later state of Barus is also associated with Northern Sumatra ^[7] .

In the 7th century, almost the entire island was occupied by the state of Srivijaya , and in the 13th-16th centuries. Sumatra was part of the Majapahit empire . In the years 1496-1904, the Aceh Sultanate was located on the island. From the 17th century until the mid- 20th century, the island was a colony of the Netherlands . Indonesia gained independence on August 17, 1945 , and Sumatra became part of it.

Brick island Buddhist temples of the Biaro built in the 11th – 14th centuries have been preserved on the island.

The population of Sumatra is 50.6 million people ( 2010 , estimated), it is the fourth most populated island in the world. The main cities are Medan (the largest city), Palembang , Padang . The population density is about 116 people / km². Sumatra is home to people of many nationalities, about 90% profess Islam .

Population of the provinces of Sumatra according to the national statistics service of Indonesia ^[8] :

The basis of the economy of Sumatra is agriculture and mining.

From agriculture, the most common cultivation of rice , rubber plants , coconut palms, coffee, tea, tobacco, spices .

Sumatra has explored several large oil fields. Oil production in Sumatra is 4/5 of all production in Indonesia.

Sumatra is rich in natural resources - oil , iron , coal , gold , nickel , tin . There are oil refineries, textile and food enterprises.

Sea transport is developed. Main ports: Belavan (near Medan), Palembang , Padang .