1 / 12

VOLCANO

detailed description of volcanoes

Anshu8
Download Presentation

VOLCANO

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. VOLCANO

  2. Definition • Volcanic Activity • Magma vs. Lava • Types of Volcanoes • Volcanic Landforms • Distribution of Volcanoes • Active volcanoes

  3. Definition • A volcano is an opening in the earth’s crust through which gases, molten rock (lava), ash, and steam are emitted. • These openings occur in weak zones of the earth’s crust.

  4. Volcanic Activity • Volcanic activity is an endogenic process. • Forms different landforms like plateaus and mountains based on eruption nature: • Plateau: Non-explosive volcanoes. • Mountain: Explosive volcanoes.

  5. Magma vs. Lava • MAGMA • LAVA • Molten rock inside the earth. • Originates mainly from the asthenosphere. • Magma that has reached the earth’s surface through a volcanic vent.

  6. Shield Volcanoes • Types of Volcanoes Cinder Cone Flood Basalt Provinces caldera Mid-Ocean Ridge Composite Volcanoes

  7. Shield Volcanoes Cinder Cone Volcanoes Composite Volcano (Stratovolcanoes) • Large, broad with gentle slopes. • Composed mainly of basalt, leading to fluid lava flows. • Examples: Hawaiian volcanoes. • Low explosiveness unless water enters the vent. • Small with steep sides. • Composed mainly of loose cinders (scoria). • Typically have a small crater at the summit. • Cone-shaped with moderately steep sides. • Layers of solid lava flows, volcanic ash, and pyroclastic materials. • Often result in explosive eruptions. Caldera Mid-Ocean Ridge Flood Basalt Provinces • Highly explosive volcanoes that collapse into themselves. • Form large depressions. • Differ from craters which are smaller depressions created by eruptive plumes. • Occur along mid-ocean ridges, stretching over 70,000 km. • Frequent eruptions in the central portions of these ridges • Large areas covered by highly fluid lava flows. • Example: Deccan Traps in India.

  8. Volcanic Landforms • Intrusive Igneous Rocks • Extrusive Igneous Rocks • Formed from lava cooling on the earth's surface. • Examples: Basalt, Andesite. • Formed from magma cooling within the earth’s crust. • Examples: Granite, Gabbro. • Types: • Batholiths: Large domes of granitic material. • Laccoliths: Dome-shaped with a level base. • Lapoliths: Saucer-shaped, concave structures. • Phacoliths: Wavy materials. • Sheets/Sills: Horizontal bodies of rock. • Dykes: Wall-like structures from vertical lava solidification. • Intrusive Igneous Rocks • Extrusive Igneous Rocks

  9. Distribution of Volcanoes • Most volcanoes are located in three major belts: • Circum-Pacific Belt (Pacific Ring of Fire) • Mid-World Mountain Belt • African Rift Valley Belt

  10. ACTIVE VOLCANOES

  11. ACTIVE VOLCANOES IN INDIA • Barren Island (Andaman Islands) • Location: • Andaman Sea, approximately 140 km from Port Blair. • Part of the Indian Union Territory of Andaman and Nicobar Islands. • Significance: • Home to Barren Volcano, the only confirmed active volcano in South Asia. • Part of a volcanic chain extending from Sumatra to Myanmar. • Geological History: • The oldest subaerial lava flows are estimated to be 1.6 million years old. • Eruption Timeline: • 1787: First recorded eruption. • 1789, 1795, 1803, 1852: Further eruptions recorded. • 1991: Eruption after approximately 150 years of dormancy, lasting around 6 months and causing significant damage to the island’s fauna. • 1995: Eruption reported. • 2004-05: Eruption linked to the 2004 Indian Ocean earthquake. • 2017: Ongoing volcanic activity spotted, linked to the 2005 eruption as per ISRO. • 2018: Eruptions linked to the 28 September 2018 earthquakes in Sulawesi, Indonesia.

  12. Thank you!

More Related