An earthquake measuring 5.6 on the Richter scale was detected around North Korea’s nuclear test site on Sunday, the Seoul military said indicating that Pyongyang has conducted its sixth nuclear test.

The artificial quake wave was detected around the Punggye-ri site in the North Hamgyeong province, according to the Joint Chiefs of Staff.

The military said it was analysing whether the temblor came from a nuke test, reports Yonhap News Agency.

Seoul’s weather agency said that the seismic wave was recorded at 12.36 p.m.

The USGS said the epicentre was recorded 24 km east-northeast of Sungjibaegam and zero km deep.

South Korean President Moon Jae-in has convened an emergency National Security Council (NSC) meeting following the earthquake and a report by North Korean state-media that Kim Jong-un inspected a hydrogen bomb being loaded into a new intercontinental ballistic missile (ICBM) after it claimed to have made a “more developed nuke”.

Since 2006, North Korea has carried out five nuclear tests, including two last year. </s> China's earthquake administration said on Saturday it had detected a magnitude 3.4 earthquake in North Korea that was a "suspected explosion", raising fears the isolated state had conducted another nuclear bomb test weeks after its last one.

BEIJING/SEOUL: A small earthquake near North Korea's nuclear test site on Saturday was probably not manmade, the nuclear proliferation watchdog and a South Korean official said, easing fears Pyongyang had exploded another nuclear bomb just weeks after its last one.

Chinese earthquake officials said the magnitude 3.4 quake detected at 0829 GMT was a "suspected explosion" but both the CTBTO, which monitors nuclear tests, and a South Korean meteorological agency official said they believed it was a natural quake.

"A key method is to look at the seismic waves or seismic acoustic waves and the latter can be detected in the case of a manmade earthquake," said the South Korean official, who asked for anonymity. "In this case we saw none. So as of now, we are categorising this as a natural earthquake."

The earthquake, which South Korea put at magnitude 3.0, was detected in Kilju county in North Hamgyong Province, where North Korea's known Punggyeri nuclear site is located, the official said.

All of North Korea's previous six nuclear tests registered as earthquakes of magnitude 4.3 or above. The last test on Sept 3 registered as a 6.3 magnitude quake.

A secondary tremor detected after that test could have been caused by the collapse of a tunnel at the mountainous site, experts said at the time. Satellite photos of the area after the Sept 3 quake showed numerous landslides apparently caused by the massive blast, which North Korea said was an advanced hydrogen bomb.

The head of the nuclear test monitoring agency CTBTO said on Saturday that analysts were "looking at unusual seismic activity of a much smaller magnitude" than the Sept 3 test in North Korea.

"Two #Seismic Events! 0829UTC & much smaller @ 0443UTC unlikely Man-made! Similar to "collapse" event 8.5 mins after DPRK6! Analysis ongoing," CTBTO Executive Secretary Lassina Zerbo said in a Twitter post, referring to Sept 3 test.

Russia’s emergency ministry says background radiation in nearby Vladivostok was within the natural range.

The U.S. Geological Survey said it could not conclusively confirm whether the quake, which it measured at magnitude 3.5, was manmade or natural.

"The depth is poorly constrained and has been held to 5 km by the seismologist," USGS said. "The Air Force Technical Applications Center (AFTAC) is the sole organisation in the U.S. federal government whose mission is to detect and report technical data from foreign nuclear explosions."

There was no immediate reaction from China's Foreign Ministry, but the news was widely reported by Chinese state media outlets and on social media.

Tensions have continued to rise around the Korean peninsula since Pyongyang carried out its sixth nuclear test, prompting a new round of U.N. sanctions.

North Korea's Foreign Minister Ri Yong Ho, currently in New York for a United Nations meeting, warned on Thursday that Kim could consider a hydrogen bomb test of an unprecedented scale over the Pacific.

Ri is due to address the United Nations later on Saturday.

U.S. President Donald Trump called the North Korean leader a "madman" on Friday, a day after Kim dubbed him a "mentally deranged U.S. dotard" who would face the "highest level of hard-line countermeasure in history".

North Korea's nuclear tests to date have all been underground, and experts say an atmospheric test, which would be the first since one by China in 1980, would be proof of the success of its weapons programme.

North Korea has launched dozens of missiles this year, several of them flying over Japan, as it accelerates a weapons programme aimed at enabling it to target the United States with a nuclear-tipped missile.

While China has been angered by North Korea's repeated nuclear and missile tests and has signed up for the increasingly tough U.N. sanctions, it has also stressed the need to resume dialogue and for all sides to take steps to reduce tensions.

In a series of meetings this week at the United Nations, Chinese Foreign Minister Wang Yi has reiterated to various foreign counterparts that apart from sanctions, the resolutions also call for dialogue to resume and that this needs to happen.

Earlier on Saturday, China said it will limit exports of refined petroleum products from Oct. 1 and ban exports of condensates and liquefied natural gas immediately to comply with the latest U.N. sanctions. It will also ban imports of textiles from North Korea.

The United States and South Korea are technically still at war with North Korea because the 1950-53 Korean conflict ended with a truce and not a peace treaty.

The North accuses the United States, which has 28,500 troops in South Korea, of planning to invade and regularly threatens to destroy it and its Asian allies. </s> China says North Korean quake ‘suspected explosion’, South Korea says likely natural

A meeting of DPRK of the central committee is held as they vow a sacred war against the US during an anti-US rally, in this undated photo released by North Korea’s Korean Central News Agency (KCNA) in Pyongyang September 22, 2017. — Reuters picBEIJING, Sept 23 — China’s earthquake administration said today it had detected a magnitude 3.4 earthquake in North Korea that was a “suspected explosion”, raising fears the isolated state had conducted another nuclear bomb test weeks after its last one.

An official at South Korea’s meteorological agency said they were analysing the tremor, which they put at magnitude 3.0, but the initial view was that it was a natural quake.

“We use several methods to tell whether earthquakes are natural or manmade,” said the official, who asked for anonymity. “A key method is to look at the seismic waves or seismic acoustic waves and the latter can be detected in the case of a manmade earthquake. In this case we saw none. So as of now we are categorising this as a natural earthquake.”

The earthquake was detected in Kilju county in North Hamgyong Province, where North Korea’s known Punggyeri nuclear site is located, the official said.

The Chinese administration said in a statement on its website that the quake, which occurred around 0830 GMT, was recorded a depth of zero kilometres.

All of North Korea’s previous six nuclear tests registered as earthquakes of magnitude 4.3 or above. The last test on September 3 registered as a 6.3 magnitude quake.

A secondary tremor detected after that test could have been caused by the collapse of a tunnel at the mountainous site, experts said at the time. Satellite photos of the area after the September 3 quake showed numerous landslides apparently caused by the massive blast, which North Korea said was a hydrogen bomb.

The head of the nuclear test monitoring agency CTBTO said today that analysts were “looking at unusual seismic activity of a much smaller magnitude” in North Korea, and that it would have more details to come.

There was no immediate reaction from China’s Foreign Ministry, but the news was widely reported by Chinese state media outlets and on social media.

Tensions have continued to rise around the Korean peninsula since Pyongyang carried out its sixth nuclear test, prompting a new round of UN sanctions.

North Korea’s Foreign Minister Ri Yong Ho, currently in New York for a United Nations meeting, warned on Thursday that Kim could consider a hydrogen bomb test of an unprecedented scale over the Pacific.

US President Donald Trump called the North Korean leader a “madman” on Friday, a day after Kim dubbed him a “mentally deranged U.S. dotard” who would face the “highest level of hard-line countermeasure in history”.

North Korea’s nuclear tests to date have all been underground, and experts say an atmospheric test, which would be the first since one by China in 1980, would be proof of the success of its weapons programme. — Reuters </s> China’s earthquake administration said on Saturday it had detected a magnitude 3.4 earthquake in North Korea that was a “suspected explosion”, raising fears the isolated state had conducted another nuclear bomb test weeks after its last one.

An official at South Korea’s meteorological agency said they were analyzing the tremor, which they put at magnitude 3.0, but the initial view was that it was a natural quake.

“We use several methods to tell whether earthquakes are natural or manmade,” said the official, who asked for anonymity. “A key method is to look at the seismic waves or seismic acoustic waves and the latter can be detected in the case of a manmade earthquake. In this case we saw none. So as of now we are categorising this as a natural earthquake.”

The earthquake was detected in Kilju county in North Hamgyong Province, where North Korea’s known Punggyeri nuclear site is located, the official said.

The Chinese administration said in a statement on its website that the quake, which occurred around 0830 GMT, was recorded a depth of zero kilometres.

All of North Korea’s previous six nuclear tests registered as earthquakes of magnitude 4.3 or above. The last test on Sept 3 registered as a 6.3 magnitude quake.

A secondary tremor detected after that test could have been caused by the collapse of a tunnel at the mountainous site, experts said at the time. Satellite photos of the area after the Sept 3 quake showed numerous landslides apparently caused by the massive blast, which North Korea said was a hydrogen bomb.

The head of the nuclear test monitoring agency CTBTO said on Saturday that analysts were “looking at unusual seismic activity of a much smaller magnitude” in North Korea, and that it would have more details to come.

There was no immediate reaction from China’s Foreign Ministry, but the news was widely reported by Chinese state media outlets and on social media.

Tensions have continued to rise around the Korean peninsula since Pyongyang carried out its sixth nuclear test, prompting a new round of U.N. sanctions.

North Korea’s Foreign Minister Ri Yong Ho, currently in New York for a United Nations meeting, warned on Thursday that Kim could consider a hydrogen bomb test of an unprecedented scale over the Pacific.

U.S. President Donald Trump called the North Korean leader a “madman” on Friday, a day after Kim dubbed him a “mentally deranged U.S. dotard” who would face the “highest level of hard-line countermeasure in history”.

North Korea’s nuclear tests to date have all been underground, and experts say an atmospheric test, which would be the first since one by China in 1980, would be proof of the success of its weapons programme. </s> (The U.S. Geological Survey reported a 5.3-magnitude seismic event in North Korea on Friday, near a nuclear test site in the northeastern part of the county.

The event at 9:30 a.m. local time had a zero depth. Its epicenter was 11 miles (18 km) east-northeast of Sungjibaegam, North Korea, the USGS said. </s> SEOUL, South Korea (AP) — South Korea’s weather agency said a magnitude 3.2 earthquake was detected in North Korea on Saturday close to where the country recently conducted a nuclear test, but it assessed the quake as natural.

The quake was detected in an area around Kilju, in northeastern North Korea, just 6 kilometers (3.7 miles) northwest of where the North conducted its sixth and most powerful nuclear test on Sept. 3, according to an official from Seoul’s Korea Meteorological Administration.

The area isn’t where natural earthquakes normally occur. A South Korean expert said the quake could have been caused by geological stress created from the recent nuclear explosion. Other possible causes include landslides or the collapsing of test structures such as tunnels, said Hong Tae-kyung, a professor at the department of Earth System Sciences at Yonsei University.

“It could be a natural earthquake that really was man-made as the nuclear test would have transferred a lot of stress,” he said. “The quake is small enough to suspect that it could have been caused by a tunnel collapse, and satellite data shows there have been many landslides in the area since the nuclear test.”

China’s official Xinhua News Agency said the country’s seismic service detected a magnitude 3.4 quake in North Korea and saw the likely cause as an explosion. But the South Korean weather agency official said the analysis of seismic waves and the lack of sound waves clearly showed that the quake wasn’t caused by an artificial explosion. She spoke on condition of anonymity, citing office rules.

Another Korea Meteorological Administration official, who also didn’t want to be named, said the agency saw the possibility of the earthquake being caused by a tunnel collapse as low.

The U.S. Geological Survey said that it detected a magnitude 3.5 quake in the area of previous North Korean nuclear tests, but that it was unable to confirm whether the event was natural.

North Korea’s weakest nuclear test, its first one, conducted in 2006, generated a magnitude 4.3 quake. The USGS measured this month’s nuclear test at magnitude 6.3. The latest test was followed by a second magnitude 4.1 quake that experts said could have been caused by landslides or a tunnel collapsing after the explosion.

Analysts examining satellite images of North Korea’s mountainous test site after the latest nuclear test said they spotted landslides and surface disturbances that were more numerous and widespread than what was seen from any of the five previous tests.

North Korea has been maintaining a torrid pace in nuclear and weapons tests as it accelerates its pursuit of nuclear weapons that could viably target the United States and its allies in Asia.

North Korea said its recent nuclear test was a detonation of a thermonuclear weapon built for its developmental intercontinental ballistic missiles. In two July flight tests, those missiles showed potential capability to reach deep into the U.S. mainland when perfected.

WHAT OTHERS ARE CLICKING ON:
• MAN HITS WOMAN IN THE FACE ON BART IN THE EAST BAY </s> U.S., European and Chinese agencies reported that the tremor was recorded at 0030 GMT. The U.S. Geological Survey and European agencies measured the tremor at a magnitude of 5.3.

A South Korea government official and the meteorological agency said it was a suspected nuclear test, and Seoul called an emergency meeting of its National Security Council.

"Today at around 9:30 a.m., we detected an artificial earthquake wave at magnitude 5.0 in the area of North Korea's Punggye-ri and we are analyzing whether it is a nuclear test," South Korea's Joint Chiefs of Staff said in a statement, referring to the North's nuclear test site.

The China Earthquake Networks Center also said the tremor was a suspected explosion. China's environment ministry began emergency radiation monitoring along its borders with North Korea in northeast China, state television reported.

Japanese Prime Minister Shinzo Abe said such a nuclear test could not be tolerated. Japan's foreign minister lodged a protest and Tokyo also sent two military jets to begin measuring for radiation.

Jeffrey Lewis of the California-based Middlebury Institute of International Studies said the highest estimates of seismic magnitude suggested this was the most powerful nuclear test conducted by North Korea so far.

He said the seismic magnitude and surface level indicated a blast with a 20- to 30-kilotonne yield. Such a yield would make this test, if confirmed, larger than the nuclear bomb dropped on the Japanese city of Hiroshima in World War Two and potentially bigger than that dropped on Nagasaki soon after.

"That's the largest DPRK test to date, 20-30kt, at least. Not a happy day," Lewis told Reuters, using the North's official title of the Democratic People's Republic of Korea.

"The important thing is that five tests in, they now have a lot of nuclear test experience. They aren't a backwards state any more," he said.

Initial analysis of North Korea's January test estimated a yield of just 6 kiloton.

South Korea's Yonhap news agency reported that the South's military believed the seismic event indicated a blast with a 10-kilotonne yield, still the largest ever conducted by the secretive North.

Kune Y. Suh, a nuclear engineering professor at Seoul National University, said the latest test, if confirmed, appeared to be two to three times larger than earlier tests, with a potential yield of more than 10 kiloton.

"So North Korea can now show off their nuclear capability proudly," Suh said.

Lassina Zerbo, the head of world monitoring agency the Comprehensive Nuclear-Test-Ban Treaty Organization, said the seismic activity registered on Friday was larger than that triggered by the North's test in January.

That test was recorded with a magnitude of 5.1, according to the U.S. Geological Survey.

The White House's National Security Council said it was aware of seismic activity on the Korean Peninsula. "We are monitoring and continuing to assess the situation in close coordination with our regional partners," an NSC statement said.

U.S.-based 38 North, a North Korea monitoring project, said in a note late on Thursday that satellite images showed fresh activity at North Korea's Punggye-ri test site.

Isolated North Korea's fourth nuclear test in January resulted in tough new U.N. sanctions. It has conducted a series of missile tests since then, including of a submarine-launched missile, in defiance of those resolutions.

North Korea has been under U.N. Security Council sanctions since it first tested an atomic device in 2006. </s> BEIJING — Research by Chinese geologists suggests that the mountain above North Korea's main nuclear test site has likely collapsed, rendering it unsafe for further testing and requiring that it be monitored for any leaking radiation.

The findings by the scientists at the University of Science and Technology of China may shed new light on North Korean President Kim Jong Un's announcement that his country was ceasing its testing program ahead of planned summit meetings with South Korean President Moon Jae-in and President Donald Trump.

The results also support some of the findings of an earlier study by another group of Chinese researchers that was published last month by the journal Geophysical Research Letters.

Nuclear explosions release enormous amounts of heat and energy, and the North's largest test in September was believed early on to have rendered the site in northeastern North Korea unstable.

Chinese authorities have said they've detected no radiation risk from samples collected along the border. Calls to those departments were not immediately answered on Thursday.

The data in the latest Chinese study was collected following the most powerful of North Korea's six nuclear device tests on Sept. 3, which is believed to have triggered four earthquakes over the following weeks. The yield of the bomb was estimated at more than 100 kilotons of TNT, at least 10 times stronger than anything the North had tested previously. (The bomb the United States dropped on Hiroshima in 1945 had a yield of about 15 kilotons.)

The University of Science and Technology of China paper, authored by Tian Dongdong, Yao Jiawen and Wen Lianxing, said the first of those earthquakes, which occurred 8 ½ minutes after the explosion, was "an onsite collapse toward the nuclear test center," while those that followed were an "earthquake swarm" in similar locations.

"In view of the research finding that the North Korea nuclear test site at Mantapsan has collapsed, it is necessary to continue to monitor any leakage of radioactive materials that may have been caused by the collapse," the authors said in a summary dated Monday and viewed Wednesday on the university's website.

The study is peer-reviewed and has been accepted for publication by the journal Geophysical Research Letters.

The Chinese study makes sense and is based on well understood research, said Rowena Lohman, a seismologist at Cornell University who wasn't part of the work. She said she believes there's an international effort that monitors these tests for radiation.

A study published last month by the journal, authored by a team led by Liu Junqing at the earthquake bureau in Jilin province along the border with North Korea, found similar results of the Sept. 3 explosion. It described the aftershock that followed seconds later as most likely a "rapid destruction of an explosion-generated cracked rock chimney due to cavity collapse."

North Korea's nuclear tests are of special concern to Beijing, since the test site near the town of Kilju is less than 60 miles from the border with China.

North Korean nuclear tests have caused seismic events in Chinese border towns and cities, forcing evacuations of schools and offices, sparking fears of wind-born radiation and leading to a backlash among some Chinese against their country's unpredictable traditional ally.

Ties between the sides have been deteriorating for years, although Kim made a long-anticipated visit to Beijing last month after China's implementation of United Nations economic sanctions reduced trade between them by as much as 90 percent.

The quakes that followed the September test were not man-made and didn't appear to cause any damage in the area. The region isn't one where earthquakes naturally occur and no quakes were detected after the five smaller nuclear tests North Korea has conducted since 2006.

Kune Yull Suh, a professor of nuclear engineering at Seoul National University, warned last year that further tests could threaten to cause a volcanic eruption at Mount Paektu, which is about 60 miles away.

On Saturday, North Korea announced it will close its nuclear testing facility and suspend nuclear and intercontinental ballistic missile tests — a move welcomed by Trump as "big progress" — and which comes ahead of the planned summit between him and Kim.

However, the North stopped short of suggesting it will give up its nuclear weapons or scale back its production of missiles and their related components. </s> South Korea’s weather agency said a magnitude 3.0 earthquake rocked North Korea on Saturday and that it appeared to be a natural occurrence. However, reports about the temblor contained conflicting information about its scale and nature.

A Chinese monitoring agency said the quake was actually stronger – at magnitude 3.4 – and that it was like caused by an explosion, Japan’s Kyoto News reported.

The quake occurred in the area where North Korea recently conducted a nuclear test, the South Korean agency reported.

The nuclear proliferation watchdog CTBTO said the unusual seismic activity detected took place about 31 miles away from previous nuclear tests and that it would be investigating, the group’s executive secretary, Lassina Zerbo, said in a Twitter post.

An official from Seoul’s Korea Meteorological Administration said Saturday’s quake was detected in an area around Kilju, in northeastern North Korea. She said the analysis of seismic waves and the lack of sound waves clearly showed that the quake wasn’t caused by an artificial explosion. She spoke on condition of anonymity, citing office rules.

The site of the quake is near where North Korea on Sept. 3 conducted its sixth and most powerful nuclear test in what it said was the detonation of a thermonuclear weapon.

Kyoto News said the temblor was detected at 4:29 p.m. local time at a depth of “0 kilometer,” a strong indication of a manmade event, according to the China Earthquake Network Center.

North Korea has been maintaining a torrid pace in nuclear and weapons tests as it accelerates its pursuit of nuclear weapons that could viably target the United States and its allies in Asia.

North Korea said its recent nuclear test was a detonation of a thermonuclear weapon built for its developmental intercontinental ballistic missiles. In two July flight tests, those missiles showed potential capability to reach deep into the U.S. mainland when perfected.

Today’s quake measures 3.4 significantly smaller than all of North Korea’s six nuclear tests.

The Associated Press contributed to this story.
A 6.3 magnitude earthquake is detected near the Punggye-ri Nuclear Test Site in Kilju County, North Korea, after North Korea tests its sixth and most powerful nuclear weapon to date. North Korean state media claims the country tested a hydrogen bomb that can be fitted on an ICBM.