Describe the topographies created by process of volcanic eruption.

Introduction: Volcanic eruptions construct diverse geomorphic landforms on the Earth's crust, categorized based on the location of cooling into Extrusive Landforms (बाह्य स्थलरूप - on surface) and Intrusive Landforms (आंतरिक / पातालीय स्थलरूप - below surface).

1. Extrusive Volcanic Landforms (धरातलीय स्थलरूप):

• 1. Volcanic Cones & Shields:
  • Cinder / Ash Cones: Steep cones built of pyroclastic scoria and ash (e.g., Parícutin in Mexico).
  • Composite Cones (Stratovolcanoes): Alternating layers of viscous andesitic lava and pyroclasts (e.g., Mt. Fuji, Mt. Vesuvius, Mt. Mayon).
  • Shield Volcanoes: Broad, low-angle domes built by fluid, low-viscosity basaltic lava (e.g., Mauna Loa in Hawaii).
• 2. Crater & Caldera (क्रेटर एवं काल्डेरा):
  • Crater: Funnel-shaped depression at the volcanic vent.
  • Caldera: Enormous collapsed depression formed by violent explosive caldera collapse (e.g., Lake Toba, Yellowstone Caldera, Lonar Crater Lake in Maharashtra).
• 3. Lava Plateaus & Flood Basalts: Fissure eruptions covering vast territories with flat basaltic flood traps (e.g., Deccan Traps of India / Malwa Plateau, Columbia River Plateau).

2. Intrusive Volcanic Landforms (Plutonic Forms - अंतर्वेधी स्थलरूप):

• Batholith (बैथोलिथ): Gigantic, deep-seated, dome-shaped granitic magma chambers forming core of mountain ranges.
• Laccolith & Lopolith: Mushroom-shaped blister intrusions (Laccolith) and saucer-shaped concave intrusions (Lopolith).
• Phacolith (फैकोलिथ): Lens-shaped magma intrusions along anticlines and synclines.
• Sill & Dyke (सिल एवं डाइक):
  • Sill: Horizontal concordant sheet of cooled magma parallel to bedding planes.
  • Dyke: Vertical/steep discordant tabular wall of magma cutting across rock strata.

Conclusion: Volcanic landforms are rich repositories of geothermal energy, volcanic mineral deposits, and fertile black soils (Regur).