UPSC Essentials | Mains answer practice — GS 3 (Week 32)

QUESTION 2

What is a tsunami? How earthquake trigger a tsunami? Discuss why tsunamis keep forming in the island country.

General points on the structure of the answers

Introduction

QUESTION 1: What is India’s first polarimetry mission X-ray Polarimeter Satellite (XPoSat)? Discuss its significance.

Introduction:

— XPoSat (X-ray Polarimeter Satellite) is India’s first dedicated polarimetry mission, designed to investigate the dynamics of bright astronomical X-ray sources under extreme conditions.

— It is the world’s second satellite-based mission dedicated to making X-ray polarimetry measurements.

— XPoSat comprises two payloads, including Indian X-ray Polarimeter (POLIX) and X-ray Spectroscopy and Timing (XSPECT). They have been built by Raman Research Institute and UR Rao Satellite Centre, both located in Bengaluru.

Body:

You may incorporate some of the following points in the body of your answer:

— The spacecraft is designated for observation from low earth orbit (~ 650 km, low inclination of ~ 6 degree).

— The two major scientific payloads on XPoSat are:

POLIX: It is the world’s first instrument designed to operate in the medium X-ray of 8 to 30 kilo electron Volt (keV) energy band.

XSPECT: It is designed to conduct fast timing and high spectroscopic resolution in a soft X-ray energy band (0.8-15 keV).

Significance of the Mission

— XPoSat will change the game by making X-ray polarisation measurements possible from bright sources in the medium energy band (8-30 keV).

— From the optical to the radio frequency band of the electromagnetic spectrum, astronomers have primarily used and relied upon spectroscopic, imaging, and timing-based data derived from either ground-based telescopes or satellite-based missions.

— XPoSat will observe two kinds of sources —

(i) Persistent sources (targeted and known sources)

(ii) Transient sources (pulsars, active galactic nuclei, magnetars)

— X-rays can become polarised for a variety of reasons. For instance, X-rays produced by interaction with materials near black holes or when exposed to high magnetic fields. Thus, through the analysis of polarised X-rays coming from stellar sources such as neutron stars, magnetars, and black holes and their surroundings.

Conclusion:

— It has an estimated mission life of about five years during which XPoSat will observe sources that emit polarised X-rays.

— The observations will take place when the magnetars or neutron stars (which are highly magnetic and exhibit a wide range of X-ray activity) pass through the Earth’s shadow, such as during the eclipse.

(Source: ISRO launches XPoSat: What is the mission and its significance? by Anjali Marar, www.isro.gov.in)

Points to Ponder

Other payloads of the Mission

POLIX

XSPECT

Related Previous Year Questions

Launched on 25th December, 2021, James Webb Space Telescope has been much in the news since then. What are its unique features which make it superior to its predecessor Space Telescopes? What are the key goals of this mission? What potential benefits does it hold for the human race? (2022)

India has achieved remarkable successes in unmanned space missions including the Chandrayaan and Mars Orbiter Mission, but has not ventured into manned space mission. What are the main obstacles to launching a manned space mission, both in terms of technology and logistics? Examine critically. (2017)

QUESTION 2: What is a tsunami? How earthquake trigger a tsunami? Discuss why tsunamis keep forming in the island country.

Introduction:

— A tsunami is a long-wavelength series of waves with a long period (time between crests). The time between wave crests can range from a few minutes to more than an hour.

— Tsunami (soo-NAH-mee) is a Japanese word meaning harbour wave. It can occur at any time of day or night.

Body:

You may incorporate some of the following points in the body of your answer:

How earthquake trigger a tsunami?

— Tsunamis are caused by earthquakes by the vertical movement of the sea floor. A tsunami does not form when the sea floor moves horizontally. Earthquakes with magnitudes greater than 6.5 are critical for tsunami generation.

— When an earthquake takes place under the ocean, a large chunk of the ocean floor can suddenly move upward or downward, leading to a sudden displacement of a large volume of water, thereby causing tsunami waves.

— When a volcano erupts in the ocean, something similar can happen. The lava flowing from the volcano displaces the water around it, which can cause a large wave to form.

Why do tsunamis keep forming in the island country?

— Tsunamis are very common in the Pacific Ocean because it is surrounded by a seismically active belt.

— The Pacific Plate, Eurasian Plate, and Indo-Australian Plate are three of the tectonic belts that are located within the Ring of Fire. These belts constantly mesh and collide, resulting in earthquakes, volcanic eruptions, and tsunamis.

— For example, Japan is situated along the ‘Pacific Ring of Fire’, which is the most active earthquake-tectonic belt in the world. In 2011, Japan was hit by a 9.0 magnitude earthquake and a resulting tsunami which devastated its northeastern coastal communities, killing around 18,000 people and displacing tens of thousands.

— It led to a nuclear meltdown at the Fukushima power plant, causing the most severe nuclear accident since the 1986 Chernobyl disaster in the Soviet Union.

— In India, the coastal region of Gujarat is vulnerable to Tsunamis from great earthquakes in Mekran
coast.

— In 2004, a 9.3 MW earthquake produced massive tsunami waves in the North Indian Ocean which brought havoc on many coastal areas in Indonesia, India, Malaysia, the Maldives, Sri Lanka, and Thailand.

Conclusion:

— However, not all earthquakes or volcanic eruptions lead to tsunamis. The formation of a tsunami can depend on a host of factors, including the shape of the ocean floor, and the earthquake’s distance and direction.

— Tsunami waves can be hundreds of feet tall and can travel as fast as jet planes over deep waters while slowing down when reaching shallow waters.

(Source: Japan earthquake triggers tsunami warning: What is a tsunami, why does it keep forming in the island country? by Alind Chauhan, nidm.gov.in)

Points to Ponder

Pacific Island Countries

Tsunami in India

Related Previous Year Questions

Discuss about the vulnerability of India to earthquake related hazards. Give examples including the salient features of major disasters caused by earthquakes in different parts of India during the last three decades. (2021)

On December 2004, tsunami brought havoc on fourteen countries including India. Discuss the factors responsible for occurrence of tsunami and its effects on life and economy. In the light of guidelines of NDMA (2010) describe the mechanisms for preparedness to reduce the risk during such events. (2017)

Previous Mains Answer Practice

UPSC Essentials: Mains answer practice — GS 1 (Week 30)

UPSC Essentials: Mains answer practice — GS 1 (Week 29)

UPSC Essentials: Mains answer practice — GS 2 (Week 31)

UPSC Essentials: Mains answer practice — GS 2 (Week 30)

UPSC Essentials: Mains answer practice — GS 3 (Week 30)

UPSC Essentials: Mains answer practice — GS 3 (Week 31)

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