North Korea’s nuclear claim could increase threat of war

By ROBERT BURNS

AP National Security Writer

WASHINGTON

North Korea’s claim to have detonated a thermonuclear weapon in an underground test has raised worldwide worry about what really happened.

Some questions and answers about what the Pentagon called an “unacceptable and irresponsible provocation” that threatens peace in Asia.

Q. Why is this a big deal?

A. The weapon test, if confirmed, could mean North Korea is on a path to possessing a bomb of far greater destructive power than the types it detonated in three previous underground tests, in 2006, 2009 and 2013. So if the North Koreans were to field such a weapon, known as a thermonuclear or hydrogen bomb, then it could raise the stakes in a long-running struggle to reunite the Korean peninsula under its own terms. That, in turn, would force tough decisions on the U.S., which has a treaty obligation to defend South Korea – with nuclear weapons if necessary.

On the other hand, North Korea is believed to already possess a number of atomic bombs and is developing longer-range missiles to deliver nuclear warheads.

Q. Might the North Koreans be bluffing?

A. That’s a possibility. White House press secretary Josh Earnest said Wednesday that early U.S. analysis of the underground explosion is “inconsistent” with the North’s announcement that it conducted a successful hydrogen bomb test. Private analysts also expressed doubts about Pyongyang’s declaration. Anthony Cordesman, a defense expert at the Center for Strategic and International Studies, said the North might have tested an enhanced atomic weapon, rather than a hydrogen bomb, as a means of celebrating the rule of its leader, Kim Jong Un.

Q. What’s the difference between an atomic bomb and a hydrogen bomb?

A. In technical terms, the difference lies in the manner in which they release energy. An atomic bomb uses nuclear fission, or the splitting of atoms, to create its energy. Hydrogen bombs use fusion, in which atoms are combined rather than split. A hydrogen bomb is vastly more powerful than an atomic bomb.

Q. How can the U.S. tell whether North Korea did test a hydrogen bomb?

A. The U.S. and the international community have many means of analyzing an underground explosion, including seismometers that measure ground motion. Also, the U.S. Air Force operates aircraft specially equipped to detect tell-tale airborne signs of a nuclear explosion, and it operates a global network of nuclear event detection equipment called the U.S. Atomic Energy Detection Systems, which can detect nuclear activity underground, underwater, in the atmosphere or in space.

Q. If North Korea did obtain a nuclear weapon that it could attach to a long-range missile, could the U.S. defend against it?

A. The Pentagon has built a battery of ground-based missiles designed to knock down long-range missiles before they hit U.S. territory, and the system is configured specifically to defend against missiles launched from North Korea. But whether the interceptors would work as intended is anyone’s guess. The interceptors are based in underground silos at Fort Greely, Alaska, and at Vandenberg Air Force Base, Calif.