The DPRK reportedly launched short-range ballistic missiles from its Musudan-ri facility in the northeastern region of the country shortly after the underground nuclear test.

The type of missile launched appears to be the KN-02 missile, capable of carrying a nuclear, chemical, or conventional payload about 130km. North Korea launched the same type of missile from the same facility back in 2005.

The KN-02 is a single-tage solid propellant missile based on the Soviet SS-21 “Scarab” — a missile in service with the Soviet Army since 1975. The KN-02 was developed to replace the inaccurate short-range Soviet artillery rocket FROG-7. Some relevant info from GlobalSecurity:

In 1983 Syria acquired SS-21 missiles supplied from the USSR. During mid-1996 Syrian missile technicians spent two weeks training in North Korea. The Syrian technicians reportedly provided North Korea with data on the SS-21 missile. In August 1996 Syria shipped Soviet-built 70km-range SS-21 Scarab missiles to North Korea.

At least, that’s what I’m told by an informed friend that that’s the missile we’re dealing with. It seems to match the description as well.