Among the most devastating endogenic processes that form Earth's surface, there are earthquakes and volcanoes. They are instantaneous yet affect human settlements and natural landscapes in the long run. Earthquakes occur as a result of tectonic motions that move seismic waves whereas volcanoes eject magma and gases hidden in the earth. These processes are vital in terms of reading plate tectonics and internal processes on the Earth. In spite of their destructive natures, they play a role in formation of landforms and balance geologically.

Key Highlights for RAS Mains

I. Earthquakes

Signification and Concept

• Earthquake: sudden shaking of the surface of Earth as a result of the liberation of energy of the lithosphere.
• The source of the earthquake is the hypocenter (focus): its projection on the ground is the epicenter.
• Resulting primarily due to plate tectonic plate motion.

Types of Earthquakes

A. Based on Causative Factors

B. Based on Focus (Depth)

Earthquakes causes

• Plate tectonics (divergent boundaries, convergent boundaries, transform boundaries)
• Volcanic activity
• Isostatic adjustments
• Human-induced activities

Effects of Earthquakes

• Land depression/ elevations
• River-course changes and coastline
• Arson and loss of lives and property
• Tsunamis, and landslides

Volcanoes

Significance and Idea

• Volcano: Crack on the surface of the earth through which magma, ash and gases spill out.
• Volcanism can be defined as any process related to magma movement as well as volcanic eruption.

Types of Volcanoes

A. Based on Eruption Frequency

B. Based on Shape

Volcanic Landscape (Intrusive Landforms)

• Batholiths: Large masses of batholiths, of batholiths.
• Laccoliths: Disks , flat on the bottom, humps in the middle
• Lopoliths (sauceed sill)
• Phacoliths, Found in folds, Lens shaped.
• Sills : Sheets like bodies of intrusion horizontal
• Dykes : Intrusions perpendicular or sloping across beddings,

Difference Between Earthquakes & Volcanoes

Conclusion for RPSC

The earthquakes and volcanoes are natural releases of the inner energy of the Earth, which, however, are quite unexpected and are usually devastating. Their mechanisms can be understood to reduce a disaster, increase safety in buildings and to plan where to build in a city. In addition, their power to sculpt the Earth surface, to fill the soils, also underlines their ambivalent nature, being both destructive and beneficial.

Also Read: The Evolution of Indian Plate