A network that enforces nuclear detente

Subject :International Relations

Section: International Conventions

Context:

Between 1945 and 1996, the world witnessed as many as 2,000 nuclear explosion tests; since then there have been six tests in all — two by India, one by Pakistan, and three by North Korea.

What happened in 1996?

CTBT was negotiated at the Conference on Disarmament in Geneva and adopted by the United Nations General Assembly in 1996.
It seeks to fully halt critical nuclear tests.
- The treaty can come into forceonly after all 44 nuclear weapon states have signed and ratified it, which hasn’t happened yet.
India, Pakistan and North Korea refused to sign the treaty.
- India sees the CTBT as no different from the Nuclear Non-Proliferation Treaty (NPT), which it vehemently opposes as discriminatory.
- Secondly, India wants to use the CTBT as a bargaining chip to gain concessions elsewhere.
The US, China, Israel, Egypt and Iran have signed but not ratified the treaty.
But the Comprehensive Test Ban Treaty Organisation ( CTBTO), which was set up to bring the treaty into force, remains hopeful.

Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO):

The organisation promotes the Treaty so that it can enter into force.
It establishes a verification regime to monitor adherence to the Treaty. The verification system is built around a network of over 325 seismic, radionuclide, infrasound and hydroacoustic (underwater) monitoring stations.
The organization was founded in 1996. It is headquartered in Vienna. It employs a staff of roughly 260 from the CTBT’s Member States.
The CTBT has achieved a key objective — preventing countries from conducting any further nuclear tests.
The CTBTO credits this to its ability to detect any nuclear test anywhere — on the ground, underground, atmosphere, or underwater.
- The organisation’s network of sensors and sensing technologies have useful spinoffs for industry and society. For example, they find applications in monsoon forecasts, tsunami warnings, tracking whale movements, and research in radionuclides.
The CTBTO’s International Monitoring System (IMS ) runs over 300 ‘monitoring stations’ around the world, including many in some of the “most remote and inhospitable Environments”.

The IMS rests on four pillars — seismic, infrasound, hydroacoustic and radionuclides.

SEISMIC
- With two seismic networks — primary (50 stations) and auxiliary (120 stations) — the IMS can detect any vibration on the ground.
- The primary network consists of seismic array stations that can determine the type of seismic wave and its origin or cause.
- The auxiliary seismic stations supplement the work of the primary stations.
- IMS seismic network can detect both (Body wave and Surface wave) types of waves.

INFRASOUND:
- The audible sound frequency is 2020,000 Hz; infrasound is below 4 Hz.
- Infrasonic waves cause minute changes in atmospheric pressure, which are measured by microbarometers.
- Infrasound travels long distances, which is useful in detecting atmospheric nuclear explosions.
- The IMS infrasound monitoring system has 60 array stations in 35 countries.
- Each array has four or more elements arranged in geometric patterns, a meteorological station, a central processing facility, and a communication system for data transmission.

HYDROACOUSTIC
- Hydroacoustic technology is used to measure changes in water pressure caused by sound waves.
- Hydroacoustic data can pinpoint the location of a nuclear explosion underwater, near the ocean surface, or near a coastline.
- Sound propagates efficiently through water but, at one level in the water, sound travel is slower but particularly efficient: the ‘sound fixing and ranging channel’ or SOFAR, at about 1,000 m The 11 IMS hydroacoustic stations keep an ear on all the oceans and provide tsunami warnings.

RADIONUCLIDE
- The presence of radionuclides — isotopes of elements that undergo radioactive decay — is the clinching evidence of a nuclear explosion.
- Isotopes of noble gases — xenon, in particular — are produced only by nuclear fission; hence, radionuclides are a ‘smoking gun’.
- The IMS has 80 radionuclide stations and 16 radionuclide laboratories.
- All the stations of IMS generate a lot of data daily, which is sent to its international data centre (IDC) in Vienna.
- The IDC today is a massive repository of data, which serves as fantastic raw material for scientific research.

Seismic waves:

Typically a seismic event generates two types of waves — body waves (P and S waves) and surface waves (Rayleigh and Love waves), which differ in speed, direction and medium of propagation.
Body waves travel through the earth’s depths, and surface waves move along the surface.

P Waves:

P waves, or Primary waves, are the first waves to arrive at a seismograph.
P waves are the fastest seismic waves and can move through solid, liquid, or gas.
They leave behind a trail of compressions and rarefactions on the medium they move through.
P waves are also called pressure waves for this reason. Certain animals, such as dogs, can feel the P waves much before an earthquake hits the crust (surface waves arrive). Humans can only feel the ramifications it has on the crust.

S Waves:

S waves, or secondary waves, are the second waves to arrive during an earthquake.
They are much slower than P waves and can travel only through solids.
It is after studying the trajectory of S waves through the layers of the earth, scientists were able to conclude that the earth’s outer core is liquid.

Rayleigh Waves:

British physicist Lord Rayleigh demonstrated the Rayleigh Waves mathematically.
A Rayleigh wave is a seismic surface wave producing a sudden shake in an elliptical motion, with no crosswise or perpendicular motion.
It moves along the ground just like a wave moves across a lake or an ocean.
The greater part of the shaking felt from an earthquake is because of the Rayleigh wave, which can be considerably bigger than other waves.
Because it rolls, it moves the ground up and down and side-to-side in the same direction that the wave is moving.

Love Waves:

Much slower than Body Waves but are the fastest surface wave and move the ground from side to side.
Love wave is also a seismic surface wave led to the horizontal shifting of the earth during an earthquake.
Confined to the surface of the crust Love waves always produce entirely horizontal motion.
They exist only in the presence of a semi-infinite medium overlain by an upper finite thickness.