Knowledge Booster: Volcanoes

Why in the News?

• Mount Lewotobi Laki-Laki, a twin-peaked volcano on Indonesia’s Flores Island, erupted on March 20, 2025.

Key Takeaways

1. Definition (US Geological Survey):

   • Volcanoes are openings, or vents where lava, tephra (small rocks), and steam erupt onto the Earth’s surface.

2. Formation:

   • Formed when material significantly hotter than its surroundings is erupted onto the surface.

   • Material includes liquid rock (magma underground, lava above ground), ash, and gases.

3. Magma Rise (NASA):

   • Divergent Boundaries: Tectonic plates move away from each other, and magma rises to fill the space, forming underwater volcanoes.

   • Convergent Boundaries: Plates move towards each other, forcing part of Earth’s crust deep into the interior, where it melts and rises as magma.

   • Hotspots: Hot areas inside the Earth heat up magma, making it less dense and causing it to rise.

Types of Volcanoes

1. Four Main Types:

   • Cinder Cones

   • Composite or Stratovolcanoes

   • Shield Volcanoes

   • Lava Domes

   • Type is determined by lava flow and its impact on the volcano and surrounding environment.

Predicting Volcanic Eruptions

1. Methods:

   • Seismographic data from earthquakes and tremors.

   • Monitoring ground deformation caused by magma movement.

   • Measuring volcanic gas emissions.

   • Analyzing changes in gravity and magnetic fields.

Ring of Fire

1. Description:

   • A string of hundreds of volcanoes and earthquake sites along the Pacific Ocean.

   • Semicircle or horseshoe shape, stretching nearly 40,250 kilometers.

2. Tectonic Plates:

   • Traces the meeting points of numerous tectonic plates, including Eurasian, North American, Juan de Fuca, Cocos, Caribbean, Nazca, Antarctic, Indian, Australian, Philippine, and other smaller plates.

3. Location:

   • Runs through 15 countries, including New Zealand, Southeast Asia, Japan, the western coast of the Americas, USA, Indonesia, Mexico, Japan, Canada, Guatemala, Russia, Chile, Peru, and the Philippines.

Famous Volcanoes

1. Mauna Loa, Hawaii:

   • Largest volcano.

2. Kilauea Volcano, Hawaii:

   • One of the most active volcanoes.

3. Fagradalsfjall Volcano, Iceland:

   • Erupted on December 18, 2023.

4. Mount Etna, Italy:

   • Largest and one of the most active volcanoes in Europe.

5. Eyjafjallajökull, Iceland:

   • 2010 eruption disrupted European air traffic.

6. Mount St. Helens, USA:

   • Major eruption in 1980.