country mount dempo
Palembang is the second - largest city on Sumatra island after Medan and the capital city of the South Sumatra province in ___MASK48___ . It is one of the oldest cities in the Malay Archipelago and Southeast Asia . Palembang is located on the Musi River banks on the east coast of southern Sumatra , with a land area of and a population of 1 , 708 , 413 people ( 2014 ). Palembang is the sixth - largest city in ___MASK48___ after Jakarta , Surabaya , Bandung , Medan and Semarang . Its built - up (" or metro ") area with Talang Kelapa and Rambutan was home to 1 , 620 , 429 inhabitants at the 2010 census . Lahat Regency is a regency of South Sumatra ( or Sumatra Selatan ) province , ___MASK48___ . It covers a total area of 4 , 076 . 06 km and a population of 370 , 146 at the 2010 Census ; the latest official estimate ( as at January 2014 ) is 397 , 094 . Dacite is an igneous , volcanic rock . It has an aphanitic to porphyritic texture and is intermediate in composition between andesite and rhyolite . The word dacite comes from Dacia , a province of the ___MASK19___ which lay between the Danube River and Carpathian Mountains ( now modern ___MASK60___ and ___MASK24___ ) where the rock was first described . Pagaralam ( Jawi : ), is a city in South Sumatra , ___MASK48___ . Before established as a definitive city , Pagaralam was an administrative city in Lahat Regency . It has an area of 633 . 66 km² and a population of 146 , 973 ( 2011 ). Sumatra is a large island in western ___MASK48___ that is part of the Sunda Islands . It is the largest island that is entirely in ___MASK48___ ( two larger islands , Borneo and New Guinea , are shared between ___MASK48___ and other countries ) and the sixth - largest island in the world at 473 , 481 km ( including adjacent islands such as the Riau Islands and Bangka Belitung Islands ). ___MASK48___ ( or ; Indonesian : ), officially the Republic of ___MASK48___ , is a unitary sovereign state and transcontinental country located mainly in Southeast Asia with some territories in Oceania . Situated between the Indian and Pacific oceans , it is the world ' s largest island country , with more than seventeen thousand islands . At , ___MASK48___ is the world ' s 14th - largest country in terms of land area and world ' s 7th - largest country in terms of combined sea and land area . It has an estimated population of over 260 million people and is the world ' s fourth most populous country , the most populous Austronesian nation , as well as the most populous Muslim - majority country . The world ' s most populous island of Java contains more than half of the country ' s population . Mount Dempo is the highest stratovolcano in South Sumatra province that rises above Pasumah Plain near Pagar Alam and adjacent with Bengkulu Province . Seven craters are found around the summit . A 400 m wide lake is found at the northwest end of the crater complex . The most recent activity has been in 2009 . Historical activity has been confined to being small - to - moderate explosive activity that produced ashfall near the volcano . A stratovolcano , also known as a composite volcano , is a conical volcano built up by many layers ( strata ) of hardened lava , tephra , pumice , and volcanic ash . Unlike shield volcanoes , stratovolcanoes are characterized by a steep profile and periodic explosive eruptions and effusive eruptions , although some have collapsed craters called calderas . The lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity . The magma forming this lava is often felsic , having high - to - intermediate levels of silica ( as in rhyolite , dacite , or andesite ), with lesser amounts of less - viscous mafic magma . Extensive felsic lava flows are uncommon , but have travelled as far as . South Sumatra Province ( Jawi : ) is a province of ___MASK48___ . It is located in the southern part of Sumatra Island , east of the Bukit Barisan Mountains . It spans and had a population of 7 , 450 , 394 at the 2010 Census ; the latest official estimate is 10 , 675 , 862 ( as at May 2015 ). The capital of the province is Palembang . A caldera is a large cauldron - like depression that forms following the evacuation of a magma chamber / reservoir . When large volumes of magma are erupted over a short time period , structural support for the crust above the magma chamber is lost . The ground surface then collapses downward into the partially emptied magma chamber , leaving a massive depression at the surface ( from one to dozens of kilometers in diameter ). Although sometimes described as a crater , the feature is actually a type of sinkhole , as it is formed through subsidence and collapse rather than an explosion or impact . Only seven known caldera - forming collapses have occurred since the start of the 20th century , most recently at Bárðarbunga volcano in ___MASK82___ .