News / Asia

Seismologists Monitor North Korea Nuclear Blast

Seismologists Monitor North Korea Nuclear Blasti
X
February 26, 2013 12:16 AM
North Korea this month set off its third nuclear test device of the past decade. And like the previous tests, this one created vibrations in the earth that could be detected around the world. Now, seismologists - scientists who normally study earthquakes - are analyzing the explosion's impact. VOA’s Bernard Shusman reports from Palisades, New York. Video was edited by Daniela Schrier
Bernard Shusman
North Korea this month set off its third nuclear test device of the past decade.  And like the previous tests, this one created vibrations in the earth that could be detected around the world.  Now, seismologists - scientists who normally study earthquakes - are analyzing the explosion's impact.  

It’s been almost 70 years since the atomic age was unleashed. The United States bombed Hiroshima and Nagasaki, which led to the end of World War II. While the memories of the devastation still linger, the events also opened up an international race for nuclear superiority.

Eight countries today consider themselves nuclear-weapon states. A ninth, Israel, neither confirms nor denies it possesses the bomb. The most recent entry is North Korea. It conducted its third nuclear underground test on February 12th.

Seismologists around the world had their monitors almost literally light up when the latest North Korean nuclear test took place.  Won-Young Kim and Paul Richards have monitored all three.  

“The first one was magnitude 4.3, the second one was 4.7, and this one was 5.1. When it becomes greater than five there is a good chance a lot of seismographic stations throughout the world will be able to record it," said Kim.

North Korea is the only country to test nuclear weapons in the 21st Century.  These scenes show North Korean engineers working in a nuclear lab.  According to seismologists, the latest test is still smaller than the weapons dropped on Japan in 1945.

A Chinese monitoring station, approximately 350 kilometers north of the test site, was the first to record the explosion.  In seconds, its reverberations reached seismologists worldwide.

At this unassuming campus in Palisades, New York, Richards and Kim analyzed the data.

“The seismograph is a recording of how the ground moves at different times," said Richards. "The preliminary waves, or the primary waves, the first arriving waves, are very strong and  impulsive. There are very weak waves in this part of the seismograph.  You hardly see them at all here.”

“We know exactly where they carried out nuclear test, and the signals are very simple, just “boom,” compared with earthquakes cracking long fault," said Kim.

The seismologists point out that nuclear devices are usually tested in shallow caves, approximately 1,500 meters-deep.   Earthquakes come many kilometers below the earth’s surface.  The difference is easy to detect.  In North Korea, according to Kim, they used the same area, but not the same site for their tests.  

“In this case what we know that they had two tunnels drilled, two tunnels, one they call East, and the other West.  And we believe this one is from the west side."

While the North Koreans celebrate their feat, Kim and Richards say that this latest test, even though small when compared to most American nuclear weapons, is very serious and that the device can do incredible damage if used as a weapon.

Video was edited by Daniela Schrier.

You May Like

Nigeria Incumbent in Tight Spot as Poll Nears

Muhammadu Buhari is running a strong challenge to Goodluck Jonathan, amid a faltering economy and Boko Haram security worries More

Video Liberia's Almost Last Ebola Patient Grateful but Still Grieving

Beatrice Yardolo tells VOA that despite her fame, life is still a struggle as she waits for government's promise of support to arrive More

Video Cambodian Land Grabs Threaten Traditional Communities

At least seven different indigenous groups in Ratanakiri depend mainly on forest products for their survival, say they face loss of their land, traditional way of life More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Liberia's Almost Last Ebola Patient Grateful but Still Grievingi
X
Benno Muchler
March 26, 2015 3:41 PM
Beatrice Yardolo was to make history as Liberia’s last Ebola patient. Liberians recently started counting down 42 days, the period that has to go by without a single new infection until the World Health Organization can declare a country Ebola-free. That countdown stopped on March 20 when there was another new case of Ebola, making Yardolo’s story a reminder that Ebola is far from over. Benno Muchler reports from Monrovia.
Video

Video Liberia's Almost Last Ebola Patient Grateful but Still Grieving

Beatrice Yardolo was to make history as Liberia’s last Ebola patient. Liberians recently started counting down 42 days, the period that has to go by without a single new infection until the World Health Organization can declare a country Ebola-free. That countdown stopped on March 20 when there was another new case of Ebola, making Yardolo’s story a reminder that Ebola is far from over. Benno Muchler reports from Monrovia.
Video

Video Cambodian Land Grabs Threaten Traditional Communities

Indigenous communities in Cambodia's Ratanakiri province say the government’s economic land concession policy is taking away their land and traditional way of life, making many fear that their identity will soon be lost. Local authorities, though, have denied this is the case. VOA's Say Mony went to investigate and filed this report, narrated by Colin Lovett.
Video

Video US, South Korea Conduct Joint Military Exercises

The Eighth U.S. Army Division and the Eighth Republic of Korea Mechanized Infantry Division put on a well orchestrated show of force for the media this week during their joint military training exercises in South Korea. VOA’s Seoul correspondent Brian Padden was there and reports the soldiers were well disciplined both in conducting a complex live fire exercise and in staying on message with the press.
Video

Video Space Program Status Disappoints 'Last Man on the Moon'

One of the films that drew big crowds last week at the annual South by Southwest festival in Austin, Texas, tells the story of the last human being to stand on the moon, U.S. astronaut Eugene Cernan. It has been 42 years since Cernan returned from the moon and he laments that no one else has gone there since. VOA’s Greg Flakus reports.
Video

Video Young Filmmakers Shine Spotlight on Giving Back

A group of student filmmakers from across the United States joined President Barack Obama at the White House this month for the second annual White House Student Film Festival. Fifteen short films were officially selected from more than 1,500 entries by students aged 6 through 18. The filmmakers and their families then joined the president and a group of celebrities for a screening of their films. VOA’s Julie Taboh reports.
Video

Video VOA Exclusive: Interview with Afghan President Ashraf Ghani

Afghan President Ashraf Ghani, during his first visit as president to Washington, gave a one-on-one interview with VOA Afghan Service reporter Said Suleiman Ashna, about his request for a change in U.S. troop levels, the threat from the Islamic State, and repairing relations with the United States and Pakistan. The interview was held at Blair House, late Sunday, in Pashto.
Video

Video California Science Center Tells Story of Dead Sea Scrolls

The ancient manuscripts were uncovered in the mid-20th century, and they are still yielding clues about life and religious beliefs in ancient Israel. As VOA's Mike O'Sullivan reports, an exhibit in Los Angeles shows how modern science is bringing the history of these ancient documents to life.
Video

Video Angelina Jolie Takes Another Bold Step

Hollywood actress and filmmaker Angelina Jolie has revealed she had her ovaries and fallopian tubes removed to lower her odds of getting cancer. Doctors say the huge publicity over her decision will help raise awareness about the importance of cancer screening. VOA’s George Putic has more

All About America

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More