Generally,volcano classified based on their volcanic activity level. Active volcano is generally defined as a volcano that has erupted at least once in the past 10,000 years. So an active volcano could be erupting right now or might have erupted only once since the last Ice Age. If a volcano is not active, it could be a dormant volcano, which means that it is a volcano that has not erupted in the past 10,000 years, but has the potential to erupt in the future.
So far, volcanoes are known located near sub-duction zones and mid-ocean ridges,while other are on mid-oceanic-plate ( inter-plate ). The volcano of these different zones could not be totally generalized each other : for example Krafla, Iceland, is about volcano on mid-oceanic-ridge could not be totally similar to volcano zoning on sub-diction zone such Merapi, Indonesia. Kilauea, Hawai, is about volcano on mid-oceanic-plate ( inter-plate ) possessing a different character to volcanoes in Indonesia.
VOLCANO OF INDONESIA
Indonesia region is known as meeting point of several tectonic plates. Indo-Australian Plate is moving northward, Eurasia Plate moves southeast direction. Both Filipino and Pacific plate move westward.The Indo - Australian plate was moved northward and partly subducted under the Eurasian plate.This subduction triggers the formation of volcanic range, from Sumatra, Java to Lesser Islands.
On another hand, the center part of Indonesia also experienced another subduction of Pacific plate that move southwesterly under the Eurasian plate. This subduction create the formation of volcanoes in the North Sulawesi, Sangihe and Halmahera.Indonesia has not less than 130 active volcanoes identified locating in Sumatra, Java, Bali - Nusatengara, Sulawesi - Arc Sangihe, and Arc Banda - Maluku. To get more overview about Indonesia volcanoes, some relevant reviews have been posted on this site included volcanoes : Merapi, Sumbing, Sindoro, Slamet, Lawu, Merbabu. Other volcanoes will be posted next time.
As other volcanoes on the globe,Volcanoes of Indonesia are formed by the accumulation of their own eruptive products, not by folding and crumpling or by uplift and erosion. Based on volcano eruption style, and eruptive products formed the volcano, Indonesia has at least two types shape of volcano: Strato Volcano and Maar Volcano. Most volcanoes in Indonesia are Strato volcano. Mostly andesite ones. ( Relevant Silica note content : Lower 53%=Basalt ,53%-63=Andesite, 63%-68%=Decite ,Over 68% Rhyolite )
Based on volcanic eruption history,active volcano of Indonesia classified in two three active volcano types: A-B-C Types.The A-Type active volcanoes are most intensively monitored by relevant authority, and Indonesia has established related Early Warning System ( locally known Status ) which is divided in to several levels locally named: Status Aktif Normal. Status Waspada. Status Siaga. Status Awas to warn citizen and visitors.So far...Merapi in Yogyakarta - Central Java is noted as Indonesian most active volcano, also one of the wold's most active volcanoes in Indonesia.
When a volcano erupt, it eruption type may different to other,in Indonesia there are at least 6 different Volcano Eruption Types identified, popular ones are Merapi Type, Strombolian Type, Plinian type and Vulcanian Type. Plinian type is most powerful ones,while Strombolian type is less powerful due to different in magma type and other factors.
History of volcano eruption in Indonesia recorded Ultra-Plinian types: popular ones were Krakatau and Tambora possessing extremely high power of volcanic eruption affected to global climate change.Today era, most frequent volcanic eruption of Indonesia are intermediate in eruption power.The past destructive Krakatau & Tambora today are in reconstructing phase through Strombolian type of eruption which is considered low in eruption power.
Each volcano has it's own volcanic hazard which is in case of volcano of Indonesia are divided in to two different Volcano Hazard : primary volcano hazard and secondary volcano hazard.Popular primary hazard in Indonesia is Pyroclastic or Pyroklastos or Nuee Ardentes while secondary hazard one is 'Lahar' (mud-flow).
Indonesia has no snow active volcano,but most part of it's structure are still 'green' by vegetation,so the air is very fresh. Mountain ecosystem of Indonesia volcanoes are mostly almost the same in type of ecosystem, consisting high-farmland ecosystem, cloudy mountain forest/montagne tropical forest, sub-alpin ecosystem and volcanic environment zone. None of them has extreme altitude, the highest active volcano of Indonesia is Kerinci volcano noted around 3805 m above sea level which is categorized as very high volcano.
Traveling to Indonesia means traveling on sub-diction zone where volcanoes could be seen almost every where either on land or ocean. Here, volcanoes play important role or have significant influential to most aspect of Indonesian life either culturally or economically. Volcano provides fertile land for farmer, also provide nice view and uniqueness of landscape for tourism sector, it provides best water resource and run function as water-catchment area, it mostly have low to highland mountain forest as well as sub alpin ecosystem which are important for biodiversity and therefore made some of them as part of Unisco's World Heritage of Nature such Kerinci.
On some area of Indonesian volcanoes, archeological remains are still existing such as at Lawu, Merbabu, Argopuro and so on, reflecting historical aspect of human being on volcanoes. Geo Living Culture such traditional ceremonies also still existed on some volcanoes such Merapi, Slamet, and so on, indicating a strong connection of Indonesians to volcanoes.
Therefore, traveling in Indonesia is actually not completed without visiting it's real volcano. So far, no doubt that gradual trekking / hiking is the best way to see real beauty of the volcano, discover more uniqueness of volcanic phenomenon as well as cultural background in the area. Thanks for visiting Indonesian volcanoes.
-----------------GOOD TO KNOW VOLCANO OF THE GLOBE ------------------------
There are more than 1000 volcanoes ( about 1,500 ) on earth are considered active. Many other volcanoes are dormant.Others are considered extinct. How ever, most these volcanoes remain hidden from view, as they are deep down on the ocean floor. About 75% of the world’s active volcanoes are underwater.
Image Contributed By: Ambo Upe Olenk + Yanto Turgo + Peo