North Korea conducted its 6th underground nuclear test Sunday and this one appears to be significantly more powerful than the previous test in September 2016. The yield of the bomb is being estimated based on the size of the earthquake it created. The USGS says the quake was a 6.3 on the Richter scale. From Yonhap News Agency:

North Korea’s apparent sixth nuclear test was estimated to have a yield of up to 100 kilotons, about four to five times stronger than the nuclear bomb dropped on Nagasaki, Japan, in 1945, the chief of the parliament’s defense committee said Sunday.

Citing a report from the military authorities, Kim Young-woo said that the explosive power of the apparent nuke tested Sunday appeared to be much stronger than the North’s fifth one estimated to have a yield of 10 kilotons.

After the test, there was a much weaker secondary quake which is believed to be the result of an underground collapse. Earlier Sunday, the DPRK released photos of Kim Jong Un inspecting a nuclear weapon intended to fit inside the nose cone of a missile:

The Wall Street Journal reports North Korean state media claimed this was a new hydrogen bomb:

Leader Kim Jong Un witnessed a hydrogen bomb being mounted onto a new intercontinental ballistic missile while visiting the Nuclear Weapons Institute, North Korea’s state media said Sunday. The state media also published what experts said could be the North’s first photos of a purported hydrogen bomb.

Mr. Kim in the report boasted that all of the components of its thermonuclear weapon are homemade, insulating the nuclear-weapons program from sanctions and “enabling the country to produce powerful nuclear weapons, as many as it wants.”

A short time after the test, state media called it a “total success.”

An MIT professor specializing in nuclear proliferation says it really doesn’t matter whether this was a true hydrogen bomb or not. What matters is that this is a city-buster:

The bottom line:

Again, that’s what North Korea is claiming. We don’t know all of that is true yet. We do know they have a missile capable of reaching most of the U.S. and, as of now, they have a bomb capable of taking out a city. The only question left is whether they can really fit one atop the other successfully. That’s apparently what those pictures above were about, i.e. showing that the new weapon design is small enough to fit inside the nose cone of a missile.

Finally, here’s a list showing all of North Korea’s nuclear tests and the magnitude of the quake caused by each: