On 6 January 2016 a small earthquake was detected near a known nuclear test site in North Korea. Within hours after the reported earthquake, information came to light that the North Koreans had tested a hydrogen bomb. The detonation is the fourth nuclear test performed by North Korea, with their first test occurring in October 2006. The test is also the first use of a hydrogen bomb by the North Koreans, with all previous tests being low yield nuclear weapons. South Korean intelligence had speculated the North Koreans were trying to develop a hydrogen bomb, and with the 6 January test, confirmed their suspicions.
Within nuclear weapons, there are two types of bombs: fission and fusion. The American atomic attacks on Hiroshima and Nagasaki during World War II were fission weapons. Fission bombs are considered low-yield weapons, generating an explosion equivalent to 10-100 kilotons of TNT. Fusion bombs, such as the hydrogen bomb, are considered thermonuclear and yield a much larger explosive force, with some weapons such as the Tsar Bomba (the largest nuclear device ever detonated) unleashing a blast yield of 50 megatons. It should be noted the significance in the difference between a low yield nuclear weapon and thermonuclear weapons. Should North Korea attack the South Korean capital city of Seoul (metropolitan population of 25.6 million people) with a low yield 10 kiloton nuke (fission), it would produce 78,000 fatalities and 270,000 injuries. A thermonuclear bomb (fusion) of one megaton would kill 1.6 million people and inflict an additional 4.7 million injuries.
Meanwhile in the Middle East, trouble erupted in the Persian Gulf on 12 January when 10 American sailors were detained by Iran after their vessels drifted into Iranian waters. The sailors were operating two small, riverine boats when it was reported they were having engine difficulties. The Iran’s Revolutionary Guards Corps (IRGC) seized the two vessels and the American sailors after they had drifted near Farsi Island, a major Iranian naval base in the Persian Gulf. The sailors were held for 22 hours before being released, along with their vessels, to American forces in the region. The United States has apologized for the incident, citing the breach of Iranian waters was unintentional. While the sailors were returned unharmed by the Iranians, it is believed that sensitive items equipment was seized by the Iranians in the incident.