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iNFRASOUND

27th September, 2024

Source: HINDU

Disclaimer: Copyright infringement not intended.

Context

In November 2024, the Comprehensive Test Ban Treaty Organization (CTBTO), is holding a workshop for scientists on using ‘infrasound’. The idea is “to create an international forum for presenting and discussing recent advancements in infrasound research and operational capabilities of global and regional networks.”

About Infrasound

Infrasound refers to sound waves with very, very low frequencies. It is a natural phenomenon that can be generated by a wide range of sources, including natural events like volcanic eruptions, earthquakes, and severe weather systems, as well as man-made activities such as explosions or industrial machinery. 

Though the CTBTO’s primary mandate is to get more countries to sign the treaty it also shares the technologies it develops for monitoring nuclear tests with the industry. 

The CTBTO’s International Monitoring System (IMS) uses a range of technologies to detect nuclear explosions. Its Infrasound Network (that is being built) is the only global monitoring network of its kind, with plans to build a network of 60 array stations in 35 countries. 

Infrasound Characteristics

Category

Details

Frequency Range

Less than 20 Hz (below the human audible range).

Sources

Natural: Earthquakes, volcanoes, ocean waves, auroras, meteor strikes, and severe storms (hurricanes, tornadoes).


Artificial: Explosions, rocket launches, industrial machinery, large-scale blasts, and wind turbines.

Propagation Characteristics

Infrasound waves can travel over vast distances through the atmosphere with minimal attenuation, allowing them to be detected thousands of kilometers away from their source​.

Applications

Environmental Monitoring: Used to detect and study natural disasters like earthquakes and volcanic eruptions.


Weather Forecasting: Tracking storms and hurricanes by studying the infrasound they generate​.


Nuclear Test Monitoring: Infrasound is used to detect clandestine nuclear tests under the Comprehensive Nuclear Test Ban Treaty.

Health Effects

Extended exposure to infrasound at high intensities has been linked to physical symptoms like headaches, nausea, and pressure sensations in sensitive individuals. It can affect the inner ear, vision, and cause vibroacoustic disease in people exposed to intense sources.

Types of sound

Type of Sound

Frequency Range

Characteristics

Sources/Examples

Applications

Audible Sound

20 Hz - 20,000 Hz

- Perceived by human ears 
- Varies from low to high pitches

Human speech, music, machinery, daily sounds

Communication, music, environmental monitoring

Ultrasound

Above 20,000 Hz

- Short wavelengths 
- High frequency 
- Inaudible to humans

Natural: Bats, dolphins 
Man-made: Ultrasound machines, sonar systems

Medical imaging (ultrasound), industrial testing (flaw detection), sonar

Subsonic Sound

Just below 20 Hz (similar to infrasound)

- Low frequency 
- Can cause vibrations

Natural: Large animals, wind

Used in animal communication, research on vibrations

Comprehensive Nuclear-Test-Ban Treaty (CTBT)

Aspect

Details

Objective

Bans all nuclear explosions for military or civilian purposes.

Components

Preamble, 17 articles, 2 annexes, and a Protocol with 2 annexes.

Entry into Force

Requires ratification by 44 specific states (Annex 2) with nuclear capabilities or research reactors. So far, 41 have signed and 35 have ratified.

Current Status (as of 2023)

Signed by 185 countries, ratified by 174. Still not ratified by key states like the U.S., China, India, Pakistan, and others.

Annex 2 States

Includes nuclear technology states like the U.S., China, Israel, India, Pakistan, North Korea, and others required for entry into force.

Monitoring System

International Monitoring System (IMS) with 337 facilities: seismic, hydro-acoustic, infra-sound, radionuclide stations to detect nuclear explosions globally.

Key Technologies for Verification

Seismic, hydro-acoustic, infra-sound, radionuclide stations, and on-site inspections (OSI).

On-Site Inspections (OSI)

Allowed once the Treaty enters into force. Can be requested if ambiguous events occur. Up to 40 inspectors can search a 1000 sq. km area for evidence of nuclear tests.

Civilian and Scientific Uses

IMS data can also be used for non-military purposes like tsunami detection, earthquake monitoring, and environmental research.

Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is an international entity designed to ensure compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which bans all nuclear explosions. While the CTBTO will formally come into effect when the CTBT enters into force, a Preparatory Commission has been in place since 1997, headquartered in Vienna, Austria.

Why has India refused to sign the CTBT?

India views the treaty as discriminatory, as it allows nuclear-armed states to retain their arsenals while prohibiting other countries from conducting tests, thus maintaining an imbalance in global nuclear disarmament. 

India argues that signing the CTBT would compromise its national security, as it needs the option to conduct nuclear tests for credible minimum deterrence, particularly given regional security challenges. 

India insists that the CTBT does not address the broader issue of complete nuclear disarmament, which it sees as essential for global security. India advocates for a universal and non-discriminatory disarmament framework.

Sources: 

HINDU

PRACTICE QUESTION

Q:Consider the following statements in reference to Comprehensive Nuclear Test Ban Treaty (CTBT): 

1. The CTBT prohibits all nuclear test explosions.

2. The CTBT has been ratified by all the Annex II states.

Select the correct statements using the codes given below:

a) 1 only

b) 2 only

c) Both 1 and 2

d) Neither 1 nor 2

Answer: a

Explanation:

Statement 1 is correct: The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions, whether for military or peaceful purposes, regardless of the yield.

Statement 2 is incorrect: CTBT requires ratification by 44 specific states (Annex 2) with nuclear capabilities or research reactors. So far, 41 have signed and 35 have ratified.