Sudden movements is a category that falls under endogenic movements. The lithospheric plate boundaries are prone to sudden geomorphic movements. Because of the pressure caused by the pushing and pulling of magma in the mantle, the plate boundaries are extremely unstable. Earthquakes and volcanoes are two examples of sudden movements that generate significant deformation in a short period of time. This article will explain the concepts of sudden movement and their examples which is an integral part of the geography syllabus. Sudden movement is an important concept for the UPSC exam.

Endogenic Movements

• Endogenic movements refer to the internal processes and phenomena that occur beneath the Earth's surface, driven by the Earth's internal heat and tectonic forces.
• These movements originate mainly from the energy generated by the radioactive decay of isotopes and heat trapped within the Earth since its formation.
• Endogenic movements can be categorized into two main types based on the manner of their occurrence and the duration over which they take place.
  • Diastrophism: These are slow movements that change the Earth's crust over extended periods.
  • Sudden Movements: These are abrupt and can cause disasters due to their rapid occurrence.
• The continuous shifting and movement of tectonic plates are significant drivers of these endogenic processes.
• The interactions at plate boundaries, whether through convergence, divergence, or transform motion, result in various endogenic activities and landform changes.

Classification of Endogenic Movements

• Diastrophic and sudden movements are two types of endogenic movements.
• Diastrophism is the term used to describe the deformation of the Earth's crust.
• Diastrophic changes are slow and can last for thousands of years.
• Sudden movements, such as earthquakes and volcanic eruptions, on the other hand, happen in a matter of seconds.
• Diastrophic movements are further divided into epeirogenic (continent formation, subsidence, and upliftment) and orogenic (mountain formation, folding, and faulting) movements.

Sudden Movements

• Sudden movements, in the context of geology and geomorphology, refer to rapid and abrupt endogenic processes that lead to significant changes in the Earth's crust over a short period of time.
• These movements can be violent and often result in natural disasters.
• The lithospheric plate boundaries are prone to sudden geomorphic movements.
• Because of the pressure caused by the pushing and pulling of magma in the mantle, the plate boundaries are extremely unstable.
• Earthquakes and volcanoes are two examples of sudden movements that generate significant deformation in a short period of time.
• While sudden movements can have destructive effects on human settlements, infrastructure, and the environment, they also play a vital role in shaping the Earth's landscape and influencing geological processes.

Earthquakes

• An earthquake is a vibration or oscillation of the surface of the Earth caused by the elasticity or the isostatic adjustment of the rocks beneath the surface of the Earth.
• The majority of earthquakes are usually caused by sudden movements along faults.
• Earthquakes can occur at any time of the year, at any hour of the day or night. It has a jolting effect.
• The sub-surface area along a fault plane, where the seismic waves are initiated, is called the focus or hypocenter of an earthquake.
• The area at the surface directly above the focus is the epicenter.
• The earth's surface vibrates as a result of a quick release of energy.
• Earthquake waves propagate outwards from the epicenter.
• These earthquake waves wreak havoc on the planet's surface.
• Most of the damage occurs closest to the epicenter, and the severity of the earthquake weakens as it moves away from it.
• Earthquakes can lead to secondary disasters, such as tsunamis, landslides, and ground ruptures.

Cause and Effect of Earthquake

• They are caused by the sudden release of accumulated stress within the Earth's crust, leading to seismic waves that shake the ground.
• They can occur at tectonic plate boundaries (convergent, divergent, transform) or within the plates due to intraplate stresses.
• Earthquakes occur when excess stored tension in rocks in the earth's interior owing to bending, faulting, or other physical processes is released as kinetic energy through weak zones on the surface.
• Coastal areas may experience uplift or subsidence as a result of these shifts.
• Alterations in contours, river courses, coastline changes, glacier surges, landslides, soil slips, mass wasting, and other effects may occur as a result of earthquakes.

Examples of Earthquake Caused due to Uplift and Subsidence

• A one-meter uplift in coastal areas was produced by an earthquake in Chile in 1822.
• An earthquake in New Zealand in 1885 resulted in a 3-meter rise.
• An earthquake in Japan in 1891 caused up to 6 meters of subsidence.

Volcanoes

• The movement of molten rock (magma) onto or towards the earth's surface through narrow volcanic vents or fissures is known as volcanism.
• A volcano is formed when molten magma from the earth's interior erupts through vents and cracks in the crust, accompanied by steam, gases such as hydrogen sulfide, sulfur dioxide, hydrogen chloride, carbon dioxide, etc., and pyroclastic material (cloud of ash, lava fragments carried through the air, and vapor).
• The type and intensity of the eruption depend on the composition of the magma and the presence of dissolved gases.
• A volcano can adopt many different shapes depending on the chemical composition and viscosity of the lava.

Conclusion

Sudden movements such as earthquakes and volcanoes create widespread devastation on the planet's surface. However, it can be concluded that these sudden movements are important to maintaining the Earth's crust's unique structure.

FAQs

MCQs

1. What is the primary cause of sudden movements in the Earth's crust?

A) Internal forces from the Earth's mantle
B) Winds and atmospheric pressure
C) Water erosion
D) Human activities

2. What geological feature is formed by diastrophic movements?

A) Volcanoes
B) Ocean ridges
C) Mountain ranges
D) River valleys

3. What is a rift valley caused by sudden movements?

A) A mountain range formed by folding
B) A depression formed by faulting
C) A plateau formed by volcanic activity
D) A river formed by erosion

4. Which of the following is a consequence of volcanic movements?

A) Earthquakes
B) Mountain formation
C) Lava eruptions and volcanic islands
D) Ocean trenches

5. Which type of plate boundary is primarily responsible for causing earthquakes?

A) Divergent boundary
B) Convergent boundary
C) Transform boundary
D) All of the above

GS Mains Questions and Model Answers

Q1: Discuss the types of endogenic movements and their impact on the Earth's surface.

Answer: Endogenic movements refer to the movements within the Earth's crust and mantle caused by internal forces. These movements can be classified into two main types: diastrophic movements and volcanic movements. Diastrophic movements include folding, faulting, and warping, which result from the horizontal or vertical displacement of the Earth's crust. These movements are responsible for the formation of mountains, valleys, and faults. Volcanic movements, on the other hand, occur when molten material from the Earth's mantle rises to the surface, resulting in volcanic eruptions and the formation of volcanic landforms such as lava plateaus, volcanic islands, and craters. Both types of movements significantly shape the Earth's surface, leading to the creation of geological features that affect landscapes, ecosystems, and human settlements.

Q2: Analyze the effects of sudden movements on human settlements and infrastructure.

Answer: Sudden movements, such as earthquakes and volcanic eruptions, can have catastrophic effects on human settlements and infrastructure. Earthquakes, in particular, can cause buildings and bridges to collapse, leading to widespread destruction and loss of life. The disruption of transportation networks and utilities can hinder rescue operations and delay recovery efforts. In coastal areas, tsunamis triggered by underwater earthquakes can devastate entire communities. Volcanic eruptions can bury towns and villages under ash and lava, displacing thousands of people and causing long-term environmental damage. In the aftermath, rebuilding efforts are often delayed due to the destruction of essential infrastructure. Sudden movements also lead to economic losses, especially in regions reliant on agriculture, tourism, and industry.

Q3: Evaluate the role of seismic activity in shaping the geography of earthquake-prone regions.

Answer: Seismic activity plays a crucial role in shaping the geography of earthquake-prone regions. Earthquakes are caused by the release of stress along fault lines, resulting in the shifting of the Earth's crust. This can lead to the formation of new landforms, such as rift valleys, mountain ranges, and fault scarps. In regions where seismic activity is frequent, the landscape is often characterized by complex geological features that are shaped by continuous tectonic movement. These regions tend to experience recurring earthquakes, which can cause further changes in the landscape over time. Earthquake-prone areas, such as the Himalayas and the Pacific Ring of Fire, have rugged topographies with significant fault lines and mountainous terrains. The ongoing seismic activity in these areas shapes both the natural environment and the human settlements within them.

Previous Year Questions on Endogenic Movements

1. UPSC CSE Prelims 2020:

Question: Which of the following is associated with the occurrence of earthquakes?

A) Volcanic eruptions
B) Plate tectonics
C) Soil erosion
D) Ocean currents

Answer: (B)

Explanation: Earthquakes are primarily associated with plate tectonics, where movements at plate boundaries result in the release of energy along fault lines.

2. UPSC CSE Mains 2021 (GS Paper 1):

Question: "How do sudden movements of the Earth's crust influence the landforms and human populations? Discuss the consequences."

Answer: Sudden movements of the Earth's crust, such as earthquakes and volcanic eruptions, have profound impacts on both landforms and human populations. These movements can reshape the Earth's surface by creating new geological features like mountains, valleys, and fault lines. They also pose significant threats to human populations, causing destruction of infrastructure, displacement of people, and loss of life. Earthquakes can result in the collapse of buildings, while volcanic eruptions can bury entire towns. The aftermath often leads to economic losses, environmental degradation, and long-term recovery challenges. These movements highlight the need for better disaster preparedness and mitigation strategies in vulnerable regions.