MISSING SUBMARINE ARA SAN JUAN: CTBTO DATA SUGGESTS EXPLOSION MAY HAVE OCCURRED

24 November 2017

Around 300 monitoring stations dotted around the globe (map) constantly monitor the planet for signs of nuclear explosions, using four complementary technologies: seismic, hydroacoustic, infrasound, and radionuclide. The data from the stations is sent directly to Vienna from where they are shared in near real-time with all states signatories of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Data is shared constantly and equally with all states for experts to conduct analysis. CTBTO also analyses data and provides these reports to states signatories several times a day.

What did CTBTO detect?

On 15 November 2017 two CTBTO hydroacoustic stations detected an unusual signal in the vicinity of the last known position of missing Argentine submarine ARA San Juan.

Hydroacoustic stations HA10 (Ascension Island) and HA04 (Crozet) detected a signal from an underwater impulsive event that occurred at 13:51 GMT on 15 November. The location of the event is as follows: Event Latitude: -46.12 deg; Event Longitude: -59.69 deg which is in the vicinity of the last known location of the ARA San Juan.

Details and data were made available to the Argentinian Authorities to support the search operations that are underway.

What are hydroacoustic stations?

The hydroacoustic stations are part of the CTBTO’s International Monitoring System (IMS) which monitors the globe continuously for signs of nuclear explosions. Low frequency underwater sound, such as the one that can be produced by a nuclear test, propagates very efficiently through water. Consequently these underwater sounds can be detected at great distances, even thousands of kilometres, from their source. This is why the IMS requires only eleven hydroacoustic stations to monitor effectively the world’s oceans.

Why did it take so long to report this signal?

Sound travels very efficiently under water and the oceans are very “noisy”. Our engineers had to sift through a very large volume of data from underwater hydrophones in far-reaching parts of the world, looking for signals which could be related to the submarine’s disappearance. Also, the IMS is designed to detect larger events: nuclear explosions. This means that a smaller signal such as the one that was detected in this case is much more difficult to isolate and locate. Picking up evidence of a relatively small source of sound in the ocean requires manual analysis of data and custom-designed software. Many thousands of possible signals from sources of noise had to be sorted through and in some cases new algorithms and approaches were developed to filter out other noise and to find this signal. This effort took considerable time by dedicated scientists.

Was this an explosion? How big was the explosion?

The system detected a short, impulsive, and broadband signal in a low frequency spectrum that is not audible to humans. The signal did not look like earthquakes or biological sounds that are commonly heard under water, but it has some characteristics in common with signals from underwater explosions.

How sure are you that this is from the missing submarine ARA San Juan?

We can only report that we found this signal that originated a few hours after the last known contact and in the vicinity of the last known reported location of the submarine, and which does not resemble to other natural sounds that are commonly recorded in the ocean.

How will this information help?

As soon as we were confident that our information was accurate, we informed the Argentinian authorities. Analysis of the data is still ongoing. Our aim is to contribute to the search and rescue efforts currently underway. We fervently hope for a positive outcome to this rescue effort.

What is the CTBT?

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans nuclear explosions by everyone, everywhere: on the Earth’s surface, in the atmosphere, underwater and underground.

Headquarters in Vienna

Since the Treaty is not yet in force, the organization is called the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). It was founded in 1996, has over 260 staff from over 70 countries, and is based in Vienna. It is headed by the Executive Secretary, Lassina Zerbo from Burkina Faso.

The multi-national cooperative search for the missing sub continues.

TYPES OF NUCLEAR WEAPONS TESTS

Nuclear explosions have been detonated in all environments: above ground, underground and underwater. Bombs have been detonated on top of towers, onboard barges, suspended from balloons, on the earth’s surface, underwater to depths of 600m, underground to depths of more than 2,400m and in horizontal tunnels. Test bombs have been dropped by aircraft and fired by rockets to altitudes of over 500 kilometres.

Atmospheric testing

Atmospheric testing refers to explosions which take place in the atmosphere.

All told, of the over 2,000 nuclear explosions detonated worldwide between 16 July 1945 (United States) and 29 July 1996 (China), 25 % or over 500 bombs were exploded in the atmosphere: over 200 by the United States, over 200 by the Soviet Union, about 20 by Britain, about 50 by France and over 20 by China.

International concern over radioactive fallout resulting from atmospheric tests escalated in the mid 1950s. In March 1954, the United States tested its hydrogen bomb Castle Bravo in the Pacific’s Marshall Islands. The Bravo test created the worst radiological disaster in the United States’ testing history. By accident, local civilians on the Marshall Islands, U.S. servicemen stationed on Rongerik atoll, and the Japanese fishing trawler Lucky Dragon, were contaminated with the fallout.

Nuclear weapon tests have been carried out in all environments: above ground, underground and underwater.

: Signing of the Partial Test Ban Treaty, 5 August 1963. Secretary of State Dean Rusk signing for the United States; Foreign Minister Andre Gromyko, signing for the Soviet Union; and Lord Hume signing for the United Kingdom.

Atmospheric testing was banned by the 1963 Partial Test Ban Treaty. Negotiations had largely responded to the international community’s grave concern over the radioactive fallout resulting from atmospheric tests. The United States, the Soviet Union and the United Kingdom became Parties to the Treaty; France and China did not. France conducted its last atmospheric test in 1974, China in 1980.

CTBTO’s infrasound IMS stations are used to detect nuclear explosions by monitoring low-frequency sound waves in the atmosphere. CTBTO Radionuclide IMS stations are designed to detect radioactive particles emanating from an atmospheric test.

High-altitude nuclear testing

: Artificial aurora over Honolulu created by the 1962 Starfish Prime test.

Around 20 nuclear tests were conducted by the United States and the Soviet Union in high altitudes or lower outer space between 1958 and 1962. The main aim of these explosions, detonated at heights between 40 and 540 kilometres, was to determine the feasibility of nuclear weapons as anti-ballistic missile defense or anti-satellite weapons. The largest such test, the 1.4 megaton U.S. Starfish Prime test in 1962, damaged and destroyed several of the satellites in orbit at the time and led to wide-spread power outages on the ground. High-altitude or outer space nuclear testing is equally banned by the 1963 Partial Test Ban Treaty as well as by the 1967 Outer Space Treaty.

Underwater testing

Underwater testing refers to explosions which take place underwater or close to the surface of the water. Relatively few underwater tests have been conducted. The first underwater nuclear test – ‘Baker’ (video) – was conducted by the United States in 1946 at its Pacific Proving Grounds in the Marshall Islands with the purpose of evaluating the effects of nuclear weapons used against naval vessels. Later, in 1955, the United States’ Operation Wigwam conducted a single underwater nuclear test at a depth of 600 m to determine the vulnerability of submarines to nuclear explosions.

Underwater nuclear explosions close to the surface can disperse large amounts of radioactive water and steam, contaminating nearby ships, structures and individuals.

Underwater nuclear testing was banned by the 1963 Partial Test Ban Treaty. The CTBTO’s hydroacoustic IMS stations are those best suited to detect nuclear explosions underwater.

Of the over 2,000 nuclear explosions detonated worldwide between 1945 and 1996, 25 % or over 500 bombs were exploded in the atmosphere.

Underground testing

Underground testing means that nuclear explosions are detonated at varying depths under the surface of the earth. These comprised the majority (i.e. about 75%) of all nuclear explosions detonated during the Cold War (1945–1989); that is, over 800 of all tests conducted by the United States and nearly 500 of all tests conducted by the Soviet Union.

When the explosion is fully contained, underground nuclear testing emits negligible fallout compared to atmospheric testing. However, if underground nuclear tests “vent” to the surface, they can produce considerable radioactive debris. Underground testing is usually evident through seismic activity related to the yield of the nuclear device.

Underground nuclear testing was banned by the 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT) that bans all nuclear explosions anywhere, by anyone.

75 % of all nuclear explosions have been conducted underground.

: Radionuclide station 56, Peleduy, Russian Federation

The CTBTO’s seismic IMS stations are used to detect nuclear explosions underground. The seismic data is combined with radionuclide data. Only the radionuclide technology can determine if an explosion is nuclear in origin; its stations and laboratories around the world monitor the presence of particulates and/or noble gases in the atmosphere.

https://www.ctbto.org/nuclear-testing/history-of-nuclear-testing/types-of-nuclear-weapons-tests/

COURTESY CTBTO

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans nuclear explosions by everyone, everywhere: on the Earth’s surface, in the atmosphere, underwater and underground.

Why is the CTBT important?
It makes it very difficult for countries to develop nuclear bombs for the first time, or for countries that already have them, to make more powerful bombs. It also prevents the huge damage caused by radioactivity from nuclear explosions to humans, animals and plants.

CTBTO EXECUTIVE SECRETARY LASSINA ZERBO ON THE UNUSUAL SEISMIC EVENT DETECTED IN THE DEMOCRATIC PEOPLE’S REPUBLIC OF KOREA

Vienna, 3 September 2017

“Our monitoring stations picked up an unusual seismic event in the Democratic People’s Republic of Korea (DPRK) today at 03:30 (UTC). So far over 100 of our stations are contributing to the analysis. The event seems to have been larger than the one our system recorded in September last year and the location is very similar to that event. Our initial location estimate shows that the event took place in the area of the DPRK’s nuclear test site. ( 03-SEP-2017 03:30:06 LAT=41.3 LON=129.1 )

Our experts are now analysing the event to establish more about its nature and we are preparing to brief our Member States today in Vienna.

“If confirmed as a nuclear test, this act would indicate that the DPRK’s nuclear programme is advancing rapidly. It constitutes yet another breach of the universally accepted norm against nuclear testing; a norm that has been respected by all countries but one since 1996. It also underlines yet again the urgent need for the international community to act on putting in place a legally binding ban on nuclear testing once and for all. I urge the DPRK to refrain from further nuclear testing and to join the 183 States Signatories who have signed the Comprehensive Nuclear-Test-Ban Treaty (CTBT). I sincerely hope that this will serve as the final wake-up call to the international community to outlaw all nuclear testing by bringing the CTBT into force,” said Lassina Zerbo, Executive Secretary of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO).

Broadcast quality footage will be posted in the CTBTO Newsroom as it becomes available.

Background

The CTBT bans all nuclear explosions. The Treaty will enter into force once signed and ratified by the remaining eight nuclear technology holder countries: China, Egypt, the DPRK, India, Iran, Israel, Pakistan, and the United States.

A verification regime is being built to monitor compliance with the Treaty. Nearly 90 percent of the 337 facilities of the International Monitoring System (IMS) are already in place; see interactive map. The system swiftly, reliably and precisely detected all five DPRK’s declared nuclear tests. After the DPRK announced nuclear test on 12 February 2013, the CTBTO was the only organization to detect radioactivity attributable to the event.

CTBTO Member States are provided with data collected by the monitoring stations, as well as data analyses prepared by the International Data Centre in Vienna, Austria. Once the Treaty has entered into force, an on-site inspection can be invoked in case of a suspicious event.

What is the CTBT?

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans nuclear explosions by everyone, everywhere: on the Earth’s surface, in the atmosphere, underwater and underground.