Indonesia has 127 active volcanoes and some others dormant, which are possibly active again seeing to some cases. There about 5 million people have activities within the danger zone of the active volcanoes in Indonesia. Volcanoes in Indonesia are part of the Pacific Ring of Fire. The 150 entries in the list below are grouped into six geographical regions, four of which belong to the volcanoes of the Sunda Arc trench system. The remaining two groups are volcanoes of Halmahera, including its surrounding volcanic islands, and volcanoes of Sulawesi and the Sangihe Islands. The latter group is in one volcanic arc together with the Philippine volcanoes. The most active volcanoes well known are Kelut and Merapi volcanoes on Java island, but recently there some other active ones, like: Mt Sinabung in Sumatra, Mt Lokon in Celebes and Mt Bromo in East Java. While some others notable for their wildest eruption in the world are: Krakatau for its global effects in 1883, Lake Toba for its supervolcanic eruption estimated to have occurred 74,000 years before present which was responsible for six years of volcanic winter, and Mount Tambora for the most violent eruption in recorded history in 1815.

There are some types of volcano in Indonesia; Stratovolcano, complex volcano, supervolcano, shield volcano, volcanic cone, caldera. In Sumatra island there are 35 active volcanos. The geography of Sumatra island is dominated by a mountain range called Bukit Barisan (lit: "a row of hills") which its range spans nearly 1,700 km (1,100 mi) from the north to the south of the island, and it was formed by movement of the Australian tectonic plate. In Java island there are 45 active volcanoes and 20 small craters and cones in the Dieng volcanic complex and the young cones in the Tengger caldera complex. Some volcanoes are grouped together in the list below because of their close location. Mount Merapi, Semeru and Kelud are the most active volcanoes in Java island.

The Lesser Sunda Islands is a small archipelago which, from west to east, consists of Bali, Lombok, Sumbawa, Flores, Sumba and the Timor islands; all are located at the edge of the Australian continental shelf. There are 30 Volcanoes in the area are formed because of oceanic crusts and the movement of the shelf itself. Some volcanoes completely form an island, for instance, the Sangeang Api island. Mount Tambora, on Sumbawa island, erupted on 5 April 1815, with a scale 7 on the VEI and is considered the most violent eruption in recorded history.

The Banda Sea in the south of the Molucca archipelago includes a small group of islands. Three major tectonic plates beneath the sea, Eurasian, Pacific and Indo-Australian plates, have been converging since the Mesozoic epoch. The 9 Volcanoes in the Banda Sea are mainly islands, but some are submarine volcanoes.

Sulawesi and Sangihe Islands have 14 Active volcanoes are found in the northern peninsula and continuously stretch to the north to Sangihe Islands. Four peninsulas dominate the shape of Sulawesi island (formerly known as Celebes). The central part is a high mountainous area, but mostly non-volcanic. The Sangihe Islands mark the border with the Philippines.

Halmahera island in the north of Molucca archipelago has been formed by the movement of three tectonic plates resulting in two intersecting mountain ranges, which form four rocky peninsulas separated by three deep bays. A volcanic arc stretches from north to south in the west side of Halmahera which are 16 volcanoes in total, some of which are volcanic islands, for instance, Gamalama and Tidore. Gamalama's island name is Ternate and it has been the centre for spice trading since the Portuguese Empire opened a fort in 1512. Due to its location as the centre for spice trading during the Age of Discovery, historical records of volcanic eruptions in Halmahera have been available as far back as the early 16th century.
Get more information for your activities during your travels in Java, Bali and other islands in Indonesia. Java Bali Trips and Team will be very happy to organize the tours and activities.