Semeru Volcano of Indonesia | 18 Jan 2021

Why in News

Recently, Semeru volcano erupted in Indonesia’s East Java province. Other volcanoes, such as the Merapi volcano (Java) and Sinabung volcano (Sumatra), also erupted recently.

Key Points

• Semeru Volcano:
  
  • Semeru - also known as "The Great Mountain" - is the highest volcano in Java and one of the most active.
  • It previously erupted in December, 2019.
  • Indonesia, with the maximum number of active volcanoes in the world, is prone to seismic upheaval due to its location on the Pacific’s Ring of Fire.
  • Semeru volcano is also the part of the Island arcs formed by the subduction of the Indo-Australian plate below Sunda Plate (part of Eurasian Plate). The trench formed here is called Sunda trench whose major section is the Java Trench.
• Pacific Ring of Fire:
  
  • The Ring of Fire, also referred to as the Circum-Pacific Belt, is a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes.
  • It traces boundaries between several tectonic plates—including the Pacific, Cocos, Indian-Australian, Nazca, North American, and Philippine Plates.

• Island Arcs:
  
  • They are long, curved chains of oceanic islands associated with intense volcanic and seismic activity and orogenic (mountain-building) processes.
    
    • An island arc typically has a land mass or a partially enclosed, unusually shallow sea on its concave side.
    • Along the convex side there almost invariably exists a long, narrow deep-sea trench.
    • The greatest ocean depths are found in these depressions of the seafloor, as in the case of the Mariana (deepest trench in the world) and Tonga trenches.
  • Prime examples of this form of geologic feature include the Aleutian-Alaska Arc and the Kuril-Kamchatka Arc.

Source: IE