Following North Korea's latest nuclear provocation, here is a timeline North Korea's six nuclear tests, going back to its first, in 2006:

Sept. 3, 2017

North Korea said it set off a hydrogen bomb in its sixth nuclear test, which judging by the earthquake it set off, appeared to be its most powerful explosion yet.

South Korea's weather agency and the Joint Chiefs of Staff said an artificial 5.7 magnitude quake occurred at 12:29 p.m. local time, in Kilju, northern Hamgyong province, the site where North Korea has conducted nuclear tests in the past. Seoul officials revised their earlier estimate of 5.6 magnitude quake. The U.S. Geological Survey called the quake an explosion with a magnitude 6.3. 

Sept. 9, 2016 

North Korea said it conducted a "higher level" nuclear warhead test explosion, which it trumpeted as finally allowing it to build "at will" an array of stronger, smaller and lighter nuclear weapons. It is Pyongyang's fifth atomic test and the second in eight months.

5.3-magnitude tremor, detected in a remote area of North Korea, near the Punggye-ri test site, was the first sign of the test. At the time, Seoul estimated it had produced the North's biggest-ever explosive yield.

The test came just after the U.S. and South Korea held their annual joint military exercises. 

Jan. 6, 2016

North Korea claimed it had conducted a hydrogen bomb test. North Korean state television claimed the regime had tested a "miniaturized" hydrogen bomb, elevating the country's "nuclear might to the next level" and providing it with a weapon to defend itself against the United States and its other enemies.

While the North was said to have deemed the test a "perfect success," Seoul's intelligence agency said the device may not have been a hydrogen bomb, South Korea's Yonhap News Agency reported, according to Reuters. Reuters also reported South Korea's meteorological agency said it hadn't detected any radiation after the supposed test. 

Japan's government also said its environmental detectors noted no radiation after the claimed test. The U.S. Air Force also sent a WC-135 Constant Phoenix "sniffer" aircraft to test for radiation. 

Feb. 12, 2013

North Korea claimed to have successfully detonated a miniaturized nuclear device at a northeastern test site, state media said, defying U.N. Security Council orders to shut down atomic activity or face more sanctions and international isolation.

South Korea confirmed that the North had indeed carried out the test, and condemned it.