Real Risk, Few Precautions (Revelation 6:12)

By WILLIAM K. STEVENS

Published: October 24, 1989

AN EARTHQUAKE as powerful as the one that struck northern California last week could occur almost anywhere along the East Coast, experts say. And if it did, it would probably cause far more destruction than the West Coast quake.

The chances of such an occurrence are much less in the East than on the West Coast. Geologic stresses in the East build up only a hundredth to a thousandth as fast as in California, and this means that big Eastern quakes are far less frequent. Scientists do not really know what the interval between them might be, nor are the deeper-lying geologic faults that cause them as accessible to study. So seismologists are at a loss to predict when or where they will strike.

But they do know that a temblor with a magnitude estimated at 7 on the Richter scale – about the same magnitude as last week’s California quake – devastated Charleston, S.C., in 1886. And after more than a decade of study, they also know that geologic structures similar to those that caused the Charleston quake exist all along the Eastern Seaboard.

For this reason, ”we can’t preclude that a Charleston-sized earthquake might occur anywhere along the East Coast,” said David Russ, the assistant chief geologist of the United States Geological Survey in Reston, Va. ”It could occur in Washington. It could occur in New York.”

If that happens, many experts agree, the impact will probably be much greater than in California.Easterners, unlike Californians, have paid very little attention to making buildings and other structures earthquake-proof or earthquake-resistant. ”We don’t have that mentality here on the East Coast,” said Robert Silman, a New York structural engineer whose firm has worked on 3,800 buildings in the metropolitan area.

Moreover, buildings, highways, bridges, water and sewer systems and communications networks in the East are all older than in the West and consequently more vulnerable to damage. Even under normal conditions, for instance, water mains routinely rupture in New York City.

The result, said Dr. John Ebel, a geophysicist who is the assistant director of Boston College’s Weston Observatory, is that damage in the East would probably be more widespread, more people could be hurt and killed, depending on circumstances like time of day, and ”it would probably take a lot longer to get these cities back to useful operating levels.”

On top of this, scientists say, an earthquake in the East can shake an area 100 times larger than a quake of the same magnitude in California. This is because the earth’s crust is older, colder and more brittle in the East and tends to transmit seismic energy more efficiently. ”If you had a magnitude 7 earthquake and you put it halfway between New York City and Boston,” Dr. Ebel said, ”you would have the potential of doing damage in both places,” not to mention cities like Hartford and Providence.

Few studies have been done of Eastern cities’ vulnerability to earthquakes. But one, published last June in The Annals of the New York Academy of Sciences, calculated the effects on New York City of a magnitude 6 earthquake. That is one-tenth the magnitude of last week’s California quake, but about the same as the Whittier, Calif., quake two years ago.

The study found that such an earthquake centered 17 miles southeast of City Hall, off Rockaway Beach, would cause $11 billion in damage to buildings and start 130 fires. By comparison, preliminary estimates place the damage in last week’s California disaster at $4 billion to $10 billion. If the quake’s epicenter were 11 miles southeast of City Hall, the study found, there would be about $18 billion in damage; if 5 miles, about $25 billion.

No estimates on injuries or loss of life were made. But a magnitude 6 earthquake ”would probably be a disaster unparalleled in New York history,” wrote the authors of the study, Charles Scawthorn and Stephen K. Harris of EQE Engineering in San Francisco.

The study was financed by the National Center for Earthquake Engineering Research at the State University of New York at Buffalo. The research and education center, supported by the National Science Foundation and New York State, was established in 1986 to help reduce damage and loss of life from earthquakes.

The study’s postulated epicenter of 17 miles southeast of City Hall was the location of the strongest quake to strike New York since it has been settled, a magnitude 5 temblor on Aug. 10, 1884. That 1884 quake rattled bottles and crockery in Manhattan and frightened New Yorkers, but caused little damage. Seismologists say a quake of that order is likely to occur within 50 miles of New York City every 300 years. Quakes of magnitude 5 are not rare in the East. The major earthquake zone in the eastern half of the country is the central Mississippi Valley, where a huge underground rift causes frequent geologic dislocations and small temblors. The most powerful quake ever known to strike the United States occurred at New Madrid, Mo., in 1812. It was later estimated at magnitude 8.7 and was one of three quakes to strike that area in 1811-12, all of them stronger than magnitude 8. They were felt as far away as Washington, where they rattled chandeliers, Boston and Quebec.

Because the New Madrid rift is so active, it has been well studied, and scientists have been able to come up with predictions for the central Mississippi valley, which includes St. Louis and Memphis. According to Dr. Russ, there is a 40 to 63 percent chance that a quake of magnitude 6 will strike that area between now and the year 2000, and an 86 to 97 percent chance that it will do so by 2035. The Federal geologists say there is a 1 percent chance or less of a quake greater than magnitude 7 by 2000, and a 4 percent chance or less by 2035.

Elsewhere in the East, scientists are limited in their knowledge of probabilities partly because faults that could cause big earthquakes are buried deeper in the earth’s crust. In contrast to California, where the boundary between two major tectonic plates creates the San Andreas and related faults, the eastern United States lies in the middle of a major tectonic plate. Its faults are far less obvious, their activity far more subtle, and their slippage far slower. 

Any large earthquake would be ”vastly more serious” in the older cities of the East than in California,  said Dr. Tsu T. Soong, a professor of civil engineering at the State University of New York at Buffalo who is a researcher in earthquake-mitigation technology at the National Center for Earthquake Engineering Research. First, he said, many buildings are simply older, and therefore weaker and more  vulnerable to collapse. Second, there is no seismic construction code in most of the East as there is in California, where such codes have been in place for decades.

The vulnerability is evident in many ways. ”I’m sitting here looking out my window,” said Mr. Silman, the structural engineer in New York, ”and I see a bunch of water tanks all over the place” on rooftops. ”They are not anchored down at all, and it’s very possible they would fall in an earthquake.”

 Many brownstones, he said, constructed as they are of unreinforced masonry walls with wood joists between, ”would just go like a house of cards.” Unreinforced masonry, in fact, is the single most vulnerable structure, engineers say. Such buildings are abundant, even predominant, in many older cities. The Scawthorn-Harris study reviewed inventories of all buildings in Manhattan as of 1972 and found that 28,884, or more than half, were built of unreinforced masonry. Of those, 23,064 were three to five stories high.

Buildings of reinforced masonry, reinforced concrete and steel would hold up much better, engineers say, and wooden structures are considered intrinsically tough in ordinary circumstances. The best performers, they say, would probably be skyscrapers built in the last 20 years. As Mr. Silman explained, they have been built to withstand high winds, and the same structural features that enable them to do so also help them resist an earthquake’s force. But even these new towers have not been provided with the seismic protections required in California and so are more vulnerable than similar structures on the West Coast.

Buildings in New York are not generally constructed with such seismic protections as base-isolated structures, in which the building is allowed to shift with the ground movement; or with flexible frames that absorb and distribute energy through columns and beams so that floors can flex from side to side, or with reinforced frames that help resist distortion.

”If you’re trying to make a building ductile – able to absorb energy – we’re not geared to think that way,” said Mr. Silman.

New York buildings also contain a lot of decorative stonework, which can be dislodged and turned into lethal missiles by an earthquake. In California, building codes strictly regulate such architectural details.

Manhattan does, however, have at least one mitigating factor: ”We are blessed with this bedrock island,” said Mr. Silman. ”That should work to our benefit; we don’t have shifting soils. But there are plenty of places that are problem areas, particularly the shoreline areas,” where landfills make the ground soft and unstable.

As scientists have learned more about geologic faults in the Northeast, the nation’s uniform building code – the basic, minimum code followed throughout the country – has been revised accordingly. Until recently, the code required newly constructed buildings in New York City to withstand at least 19 percent of the side-to-side seismic force that a comparable building in the seismically active areas of California must handle. Now the threshold has been raised to 25 percent.

New York City, for the first time, is moving to adopt seismic standards as part of its own building code. Local and state building codes can and do go beyond the national code. Charles M. Smith Jr., the city Building Commissioner, last spring formed a committee of scientists, engineers, architects and government officials to recommend the changes.

”They all agree that New York City should anticipate an earthquake,” Mr. Smith said. As to how big an earthquake, ”I don’t think anybody would bet on a magnitude greater than 6.5,” he said. ”I don’t know,” he added, ”that our committee will go so far as to acknowledge” the damage levels in the Scawthorn-Harris study, characterizing it as ”not without controversy.”

For the most part, neither New York nor any other Eastern city has done a detailed survey of just how individual buildings and other structures would be affected, and how or whether to modify them.

”The thing I think is needed in the East is a program to investigate all the bridges” to see how they would stand up to various magnitudes of earthquake,” said Bill Geyer, the executive vice president of the New York engineering firm of Steinman, Boynton, Gronquist and Birdsall, which is rehabilitating the cable on the Williamsburg Bridge. ”No one has gone through and done any analysis of the existing bridges.”

In general, he said, the large suspension bridges, by their nature, ”are not susceptible to the magnitude of earthquake you’d expect in the East.” But the approaches and side spans of some of them might be, he said, and only a bridge-by-bridge analysis would tell. Nor, experts say, are some elevated highways in New York designed with the flexibility and ability to accommodate motion that would enable them to withstand a big temblor.

Tunnels Vulnerable

The underground tunnels that carry travelers under the rivers into Manhattan, those that contain the subways and those that carry water, sewers and natural gas would all be vulnerable to rupture, engineers say. The Lincoln, Holland, PATH and Amtrak tunnels, for instance, go from bedrock in Manhattan to soft soil under the Hudson River to bedrock again in New Jersey, said Mark Carter, a partner in Raamot Associates, geotechnical engineers specializing in soils and foundations.

Likewise, he said, subway tunnels between Manhattan and Queens go from hard rock to soft soil to hard rock on Roosevelt Island, to soft soil again and back to rock. The boundaries between soft soil and rock are points of weakness, he said.

”These structures are old,” he said, ”and as far as I know they have not been designed for earthquake loadings.”

Even if it is possible to survey all major buildings and facilities to determine what corrections can be made, cities like New York would then face a major decision: Is it worth spending the money to modify buildings and other structures to cope with a quake that might or might not come in 100, or 200 300 years or more?

”That is a classical problem” in risk-benefit analysis, said Dr. George Lee, the acting director of the Earthquake Engineering Research Center in Buffalo. As more is learned about Eastern earthquakes, he said, it should become ”possible to talk about decision-making.” But for now, he said, ”I think it’s premature for us to consider that question.”

Iran Threatens to Strike Back at Israel

Iran threatens retaliation after what it calls possible cyberattack on nuclear site

DUBAI: Iran will retaliate against any country that carries out cyberattacks on its nuclear sites, the head of civilian defence said, after a fire at its Natanz plant which some Iranian officials said may have been caused by cyber sabotage. The underground Natanz Fuel Enrichment Plant (FEP) is one of several Iranian facilities monitored by inspectors of the International Atomic Energy Agency, the U.N. nuclear watchdog.

Iran`s top security body said on Friday that the cause of the “incident” at the nuclear site had been determined, but “due to security considerations” it would be announced at a convenient time.Iran`s Atomic Energy Organisation (AEOI) initially reported an “incident” had occurred early on Thursday at Natanz, located in the desert in the central province of Isfahan.

It later published a photo of a one-storey brick building with its roof and walls partly burned. A door hanging off its hinges in the photo suggested that there had been an explosion inside the building. “Responding to cyber attacks is part of the country`s defence might. If it is proven that our country has been targeted by a cyber attack, we will respond,” civil defence chief Gholamreza Jalali told state TV late on Thursday.

An article issued on Thursday by state news agency IRNA addressed what it called the possibility of sabotage by enemies such as Israel and the United States, although it stopped short of accusing either directly.

“So far Iran has tried to prevent intensifying crises and the formation of unpredictable conditions and situations,” IRNA said. “But the crossing of red lines of the Islamic Republic of Iran by hostile countries, especially the Zionist regime and the U.S., means that strategy…should be revised.”

SUSPICIONS

Three Iranian officials who spoke to Reuters on condition of anonymity said they believed the fire was the result of a cyber attack, but did not cite any evidence. One of the officials said the attack had targeted the centrifuge assembly building, referring to the delicate cylindrical machines that enrich uranium, and said Iran`s enemies had carried out similar acts in the past.Two of the officials said Israel could have been behind the Natanz incident, but offered no evidence.

Asked on Thursday evening about recent incidents reported at strategic Iranian sites, Israeli Prime Minister Benjamin Netanyahu told reporters: “Clearly we can’t get into that.” The Israeli military and Netanyahu`s office, which oversees Israel`s foreign intelligence service Mossad, did not immediately respond to Reuters queries on Friday.

In 2010, Stuxnet computer virus, which is widely believed to have been developed by the United States and Israel, was discovered after it was used to attack Natanz facility. Natanz was built in secret without the IAEA`s knowledge but was exposed by an Iranian opposition group in 2002. Iran acknowledged the site’s existence in 2003.

The underground Natanz site remains the centrepiece of Iran`s enrichment programme, though Tehran denies ever seeking nuclear weapons, saying its atomic programme is only for peaceful purposes. Iran curbed its nuclear work in exchange for the removal of most global sanctions under an accord reached with six world powers in 2015 but has reduced compliance with the deal`s restrictions since the United States withdrew in 2018.

Nuclear Testing Will Start Again

Nuclear Testing, Never Again

July 3, 2020

Congress must step in and slam the door shut on the idea of resuming nuclear testing, especially if its purpose is to threaten other countries, writes Daryl G. Kimball.

By Daryl G. Kimball
in Washington, D.C.

Inter Press Service

Seventy-five years ago, on July 16, the United States detonated the world’s first nuclear weapons test explosion in the New Mexican desert. Just three weeks later, U.S. Air Force B-29 bombers executed surprise atomic bomb attacks on the cities of Hiroshima and Nagasaki, killing at least 214,000 people by the end of 1945, and injuring untold thousands more who died in the years afterward.

Since then, the world has suffered from a costly and deadly nuclear arms race fueled by more than 2,056 nuclear test explosions by at least eight states, more than half of which (1,030) were conducted by the United States.

But now, as a result of years of sustained citizen pressure and campaigning, congressional leadership, and scientific and diplomatic breakthroughs, nuclear testing is taboo.

The United States has not conducted a nuclear test since 1992, when a bipartisan congressional majority mandated a nine-month testing moratorium. In 1996 the United States was the first to sign the Comprehensive Test Ban Treaty (CTBT), which verifiably prohibits all nuclear test explosions of any yield.

Today, the CTBT has 184 signatories and almost universal support. But it has not formally entered into force due to the failure of the United States, China, and six other holdout states to ratify the pact.

Door to Testing Ajar

As a result, the door to nuclear testing remains ajar, and now some White House officials and members of the Senate’s Dr. Strangelove Caucus are threatening to blow it wide open.

According to a May 22 article in The Washington Post, senior national security officials discussed the option of a demonstration nuclear blast at a May 15 interagency meeting.

A senior official told the Post that a “rapid test” by the United States could prove useful from a negotiating standpoint as the Trump administration tries to pressure Russia and China to engage in talks on a new arms control agreement.

Making matters worse, in a party-line vote last month, the Senate Armed Services Committee approved an amendment by Sen. Tom Cotton (R-Ark.) to authorize $10 million specifically for a nuclear test if ordered so by President Donald Trump.

U.S. Sen. Tom Cotton, at left, during a 2015 visit to a Patriot missile tactical site at Osan Air Base, Korea. (William Leasure, Wikimedia Commons)

Such a test could be conducted underground in just a few months at the former Nevada Test Site outside Las Vegas.

The idea of such a demonstration nuclear test blast is beyond reckless. In reality, the first U.S. nuclear test explosion in 28 years would do nothing to rein in Russian and Chinese nuclear arsenals or improve the environment for negotiations.

Rather, it would raise tensions and probably trigger an outbreak of nuclear testing by other nuclear actors, leading to an all-out global arms race in which everyone would come out a loser.

Triggering Other Nuclear-Armed Countries

Other nuclear-armed countries, such as Russia, China, India, Pakistan, and North Korea would have far more to gain from nuclear testing than would the United States. Over the course of the past 25 years, the U.S. nuclear weapons labs have spent billions to maintain the U.S. arsenal without nuclear explosive testing.

Other nuclear powers would undoubtedly seize the opportunity provided by a U.S. nuclear blast to engage in multiple explosive tests of their own, which could help them perfect new and more dangerous types of warheads.

Moves by the United States to prepare for or to resume nuclear testing would shred its already tattered reputation as a leader on nonproliferation and make a mockery of the State Department’s initiative for a multilateral dialogue to create a better environment for progress on nuclear disarmament. The United States would join North Korea, which is the only country to have conducted nuclear tests in this century, as a nuclear rogue state.

North end of Yucca Flat at the Nevada test site, where most tests have been conducted. (National Nuclear Security Administration Nevada Site Office, Wikimedia Commons)

As Dr. Lassina Zerbo, executive secretary of the Comprehensive Test Ban Treaty Organization, said on May 28, “[A]ctions or activities by any country that violate the international norm against nuclear testing, as underpinned by the CTBT, would constitute a grave challenge to the nuclear nonproliferation and disarmament regime, as well as to global peace and security more broadly.”

Talk of renewing U.S. nuclear testing would dishonor the victims of the nuclear age. These include the millions of people who have died and suffered from illnesses directly related to the radioactive fallout from tests conducted in the United States, the islands of the Pacific, Australia, China, North Africa, Russia, and Kazakhstan, where the Soviet Union conducted 468 of its 715 nuclear tests.

Tragically, the downwinders affected by the first U.S. nuclear test, code-named “Trinity,” are still not even included in the U.S. Radiation Effects Compensation Act program, which is due to expire in 2022.

Congress must step in and slam the door shut on the idea of resuming nuclear testing, especially if its purpose is to threaten other countries. As Congress finalizes the annual defense authorization and energy appropriations bills, it can and must enact a prohibition on the use of funds for nuclear testing and enact safeguards that require affirmative House and Senate votes on any proposal for testing in the future.

Eventually, the Senate can and must also reconsider and ratify the CTBT itself. As a signatory, the United States is legally bound to comply with CTBT’s prohibition on testing, but has denied itself the benefits that will come with ratification and entry into force of the treaty.

Nuclear weapons test explosions are a dangerous vestige of a bygone era. We must not go back.

Daryl G. Kimball is executive director of the Arms Control Association (ACA) and publisher of the organization’s monthly journal, “Arms Control Today.”

The Growing Nuclear Horns (Daniel)

POLL: As China, North Korea, Russia and Iran tensions grow, who is biggest threat to West?

TENSIONS have been flaring between the West and China, North Korea, Russia and Iran – but who do you think poses the biggest threat?

By KATIE HARRIS

PUBLISHED: 15:24, Fri, Jul 3, 2020

Boris Johnson accused Beijing of a “clear and serious breach” of its treaty with Britain when the territory was handed back to China in 1997.

The UK is pushing forward with its plan to give three million Hong Kong residents the right to settle in Britain, prompting China to warn of retaliation.

The draconian new security law – which came into effect on Tuesday night – makes activities deemed subversive or secessionist punishable by imprisonment.

Meanwhile, China rejected criticism by the US over its plan to hold military exercises in the South China Sea.

The US Defense Department warned in a statement on Thursday that the provocative move was “counter-productive to efforts at easing tensions and maintaining stability”.

China announced last week it was holding five days of drills starting on July 1 near the Paracel Islands, which are claimed by both Beijing and Vietnam.

Elsewhere, denuclearisation talks between North Korea and the US are at a deadlock.

Tensions between North Korea and South Korea reached boiling point last month when Kim Jong-un blew up a joint liaison office which was built in a bid to improve ties between the two Koreas.

And the North Korean leader threatened military action over propaganda leaflets sent from South Korea.

US President Donald Trump first met Kim in 2018 for a summit in Singapore to persuade North Korea to give up its nuclear weapons programme.

Their second meeting in Vietnam in 2019 broke down without an agreement.

The pair met again at the demilitarized zone between the two Koreas later that year but no progress has been made.

It comes as Iran continues to roll back on its commitments to the 2015 nuclear deal with six world powers including the UK.

Tehran agreed to limit its nuclear activities in return for relief of crippling sanctions.

But Iran has rolled back on its commitments to the deal since Mr Trump pulled out in 2018 and reimposed sanctions, with the US President branding the agreement “decaying and rotten” and “defective to its core”.

In Russia, changes to the constitution which could pave the way for Vladimir Putin to be president until 2036 come into force on July 4.

In a nationwide poll 78 percent backed the changes with the Kremlin hailing the vote as a triumph.

However critics have branded the move illegal and illegitimate.

Relations between Britain and Russia have been at a low since the Salisbury poisonings in 2018.

Russia’s Powerful Nuclear Horn (Daniel 7)

Russia Touts S-500’s Ability to Destroy Hypersonic Weapons in Space

The Moscow Times

Russian defense officials say the S-500 Prometheus could enter service as soon as 2020. army-news.ru

Russia’s advanced S-500 air defense system is capable of destroying hypersonic weapons and satellites in near space, the head of Russia’s air and space forces has said.

The S-500 Prometheus, which Russian defense officials say could enter service as soon as 2020, is touted as being capable of intercepting stealth warplanes. President Vladimir Putin has said that the S-500 is capable of operating in “ultra-high altitudes including near space.”

Sergei Surovikin, the head of Russia’s Aerospace Forces, said this capability will allow the S-500 to destroy low-orbit satellites, as well as hypersonic and space weapons, in addition to its primary targets intermediate-range ballistic missiles.

“The characteristics inherent in the S-500 surface-to-air missile make it possible to destroy… hypersonic weapons of all modifications, including in near space,” Surovikin told the Defense Ministry’s Red Star publication Friday.

The S-500 can be classified as the first generation of space defense systems, since in the future it will be able to destroy low-orbit satellites and space weapons,” Surovikin said.

The surface-to-air missile was reported to have carried out the world’s longest missile test in 2018.

Russia and the United States have developed hypersonic missiles in recent years as the countries trade blame over arms control treaty violations and attempt to restart nuclear talks.

The S-500 was initially scheduled for delivery in 2025 after preliminary tests in 2020. Deputy Defense Minister Alexei Krivoruchko noted in February that air defense troops tested the S-500 using “new and unparalleled missiles” in 2019.

“We’re confident that the new system will be ready for delivery to the armed forces in 2020,” Krivoruchko told the Concern Radio-Electronic Technologies’ (KRET) monthly magazine at the time.

Palestinians Protest Israel’s Annexation Plans Outside the Temple Walls (Revelation 11)

Palestinians Protest Israel’s Annexation Plans in Gaza, Ramalla

Thousands of Palestinians participated in a large rally in Gaza, on Wednesday, expressing their rejection of the occupation states annexation plans, Quds News Network reported.

Political leaders and civilians attended the demonstration, raising Palestinian flags and reciting slogans against the expropriation of the Palestinian Jordan Valley, and other parts of the occupied West Bank.

Leader of Hamas, Fatah, the Islamic Jihad, and Fida attended, asserting that the Palestinian people will cripple the Israeli schemes.

The Palestinian resistance reiterated in a statement, that the so called ‘Deal of the Century’ is absolutely rejected by the Palestinian people, as it denies their human rights and violates international law.

Iranian Nuclear Plant Attacked

Iran nuclear: ‘Incident’ at Natanz uranium enrichment facility

@aeoinews

Iran’s Atomic Energy Organisation released a photo purportedly showing the damaged building

A fire has reportedly damaged a building at a nuclear facility in Iran.

Atomic Energy Organisation of Iran (AEOI) spokesman Behruz Kamalvandi said there was an incident in “one of the industrial sheds under construction” at the Natanz uranium enrichment plant.

There were no fatalities or concerns about contamination, he added.

The AEOI later published a photo showing a partly burned building, which US-based analysts identified as a new centrifuge assembly workshop.

Centrifuges are needed to produce enriched uranium, which can be used to make reactor fuel but also nuclear weapons.

Meanwhile, in a statement sent to BBC Persian journalists before the AEOI’s announcement, an unknown group calling itself “Cheetahs of the Homeland” claimed it had attacked the building. The group said its members were part of “underground opposition with Iran’s security apparatus”.

The claim could not immediately be verified by the BBC.

The International Atomic Energy Agency (IAEA), which monitors Iran’s compliance with a 2015 nuclear deal struck with world powers, said it was aware of the reports from Natanz and currently anticipated no impact on its verification activities.

The incident comes six days after an explosion near the Parchin military complex.

The Iranian authorities said the blast was caused by “leaking gas tanks” at the site, but analysts said satellite photographs showed it happened at a nearby missile production facility.

Parchin is where Western powers suspect Iran carried out tests related to nuclear warhead detonations more than a decade ago. Iran insists its nuclear programme is peaceful and denies that it sought to develop nuclear weapons.

Natanz, which is about 250km (155 miles) south of the capital Tehran, is Iran’s largest uranium enrichment facility.

Mr Kamalvandi told Iranian media that Thursday morning’s incident “took place in one of the industrial sheds being built in the open-air part of the Natanz site”.

“There were no fatalities and no damage was done to the ongoing activities at the complex,” he said.

“As the complex is not active, there is no concern about [radioactive] contamination. A team of experts of the AEOI are at the site investigating the reasons behind the incident,” he added.

The governor of Natanz city, Ramazanali Ferdowsi, was later quoted by Tasnim news agency as describing the incident as a fire. Fire fighters and rescue teams were deployed to the site, he added.

The Natanz enrichment facility has three large underground halls capable of holding tens of thousands of centrifuges operating in cascades. Uranium hexafluoride gas is fed into them to separate out the most fissile isotope, U-235.

The 2015 nuclear deal saw Iran agree only to produce low-enriched uranium, which has a 3-4% concentration of U-235 and can be used to produce fuel for nuclear power plants. Weapons-grade uranium is 90% enriched or more.

In November, Iran unveiled advanced centrifuges at Natanz

Iran also agreed to install no more than 5,060 of the oldest and least efficient centrifuges at Natanz until 2026, and not to carry out any enrichment at its other underground facility, Fordo, until 2031.

Last year, Iran began rolling back these commitments in retaliation for US President Donald Trump’s decision to abandon the nuclear accord and reinstate crippling economic sanctions lifted by his predecessor Barack Obama.

In November, Iran said it had doubled the number of advanced centrifuges being operated at Natanz and begun injecting uranium hexafluoride gas into centrifuges at Fordo.