North Korea Nuclear Test Causes magnitude 4.7 Earthquake
FEWW can confirm with 0.95 certainty that the magnitude 4.7 North Korea earthquake that occurred near Chongjin earlier today was caused by an underground nuclear test.
Based on FEWW estimates, the NK nuclear test had a blast yield of about 12 kilotons (TNT equivalent), or 50TJ (50 x 10¹²J), almost similar to the first US atom bomb detonated above Hiroshima.
Date-Time: Monday, May 25, 2009 at 00:54:43 UTC
Location: 41.331°N, 129.011°E
Depth: 0 km (~0 mile) set by location program [occurred at a shallow depth]
Region: NORTH KOREA
- 75 km (45 miles) NNW of Kimchaek, North Korea
- 95 km (60 miles) SW of Chongjin, North Korea
- 180 km (110 miles) SSW of Yanji, Jilin, China
- 380 km (235 miles) NE of PYONGYANG, North Korea
Location Uncertainty: horizontal +/- 5.3 km (3.3 miles); depth fixed by location program
Parameters: NST= 76, Nph= 76, Dmin=474.4 km, Rmss=0.8 sec, Gp= 68°, M-type=body wave magnitude (Mb), Version=8
Source: USGS NEIC (WDCS-D)
Event ID: us2009hbaf
Seismic Hazard Map [USGS]
Tectonic Summary: USGS says it cannot cannot confirm that the recent event was a nuclear test, however it says the quake was shallow and located in the vicinity of the October 2006 North Korean nuclear test.
How did the energy yield compare with other nuclear detonations/ earthquakes?
1. Hiroshima atom bomb had an energy yield of about 63TJ, or 15 kilotons (TNT equivalent). [Note: Estimates vary between 12-18 kilotons.]
2. Fat Man, the atomic bomb detonated over Nagasaki, yielded about 88TJ of energy, the equivalent of 21 kilotons of TNT.
3. Sichuan earthquake, China, 2008, which left up to 90,000 people dead, was a magnitude 7.9 Mw, which released about 3.3 EJ of energy (3.3 exajoules), or the TNT equivalent of 0.71 gigaton. [ Note: Various sources reported quake magnitude at 7.8 to 8.0 Mw.]
4. Sumatra Earthquake, which caused the deadly 2004 tsunami, was a magnitude 9.2 earthquake with an estimated yield of about 91 billion tons (91 gigatons of TNT). [Note: The Sumatra earthquake has been reported at different magnitudes of 9.1 – 9.3 Mw.