Indonesia archipelago is one of the largest volcanic area in the world. The country is archipelagocal volcano located in sub-diction of two points of plate.One point of plate under the other plate.
Simply...as expert says, the archipelago is above the Indo-Australian and Eurasian sub-diction system
Most interesting thing is one of the main line of the world's volcano pass through that sub-diction archipelago, so that creates different view between volcanic island and non volcanic island.A curve line connecting to active and non active volcanoes can be tracked/explored along this archipelago.
That curve line is started from Sumatra island and continued to Java island, Bali,Lombok,Sumbawa,Flores, archipelago
Serwati,Banda,Ambon,Bacan,Makian,Tidore,Ternate,Jailolo, and Morotai island.The line is interrupted on this island and move to westernsite of the island. This line started again in north Sulawesi, via Siau and Sangir, as well as pass through eastern side of Phillipe until corner of of west. Curve line at east in Banda pass through non-volcanic area with space 1600 km, and end in volcanic area which was discovered by Dampier in 1699 at eastern coast of Irian. From this area, the line of other volcano pass through New Britannia, New Irlandia (Pasific Ocean),archipelago Solomon, and outskirts of most east of archipelago Nusantara (Indonesia).
Island which are passed through by that volcanic line dominated by volcanic land view and often experienced earthquake.Low earthquake recorded occurred in interval of some weeks to month, while hight earthquake occurred every years.
With no less than 129 active volcanoes and dozen of earthquake each year make this archipelagocal volcano as one of the world's most active geological zones.