Nuclear Tests and Earthquakes

　Underground nuclear tests conducted in North Korea are known to cause strong seismic waves that are detected by meteorological observers and authorities throughout the region.

　Could the ripple effects trigger real earthquakes?

　 If the answer is yes, neighbors such as South Korea, China, Japan as well as the whole international community would have an extra serious reason for calling upon North Korea to stop such dangerous experiments immediately.

　1. Observers have noticed that nowadays, earthquakes occur much more frequently in South Korea, a country where such phenomenon used to be very rare, at least until the turn of the century. The strongest earthquake ever to be recorded in South Korea occurred on September 12, 2016, just 3 days after North Korea conducted its 5th nuclear test.

　 That was the 2nd North Korean test conducted in 2016; the first one was conducted in January.

　2. The same year, in Japan, large-scale earthquakes hit coastal prefectures such as Kumamoto (in April) and Tottori (in October) in the southwest, that face the Korean Peninsula, with the East China Sea and the Sea of Japan in between.

　There was little in the way of forewarning, as these prefectures used to be considered among the luckier places, relatively free of big tremors in a country known for live volcanoes and frequent geological disturbances, and this has set people wondering why they had to occur.

　3. One explanation must be sought in climate change. In recent years, East Asia has experienced its dramatic effects, including an increase in the number of typhoons that hit and traverse Japan and South Korea, and whirlwinds approaching tornados, much to the surprise and fear of the native people. A drastic example may be the catastrophic earthquake that hit the Tohoku region in 2011.

　4. At the same time, however, it may be worth considering the possibility of a correlation with underground nuclear tests in North Korea, as listed at the end. After all, both the Korean Peninsula and the southwestern half of Japan (including Kumamoto and Tottori) lie on the same Eurasian tectonic plate.

(Note) In general terms, Honshu, or the main island of Japan, rests on 2 tectonic plates that meet along the Tectonic Line that runs just to the east of the Japanese Alps, to connect Itoigawa and Shizuoka. The part of Honshu extending northeastwards from this line is on the North American plate, and southwestwards, on the Eurasian plate.

　5. Nuclear tests in North Korea have caused shock waves throughout the region strong enough to be observed by meteorological authorities in all neighboring countries, including Japan, despite the separating oceans.

　In fact, their magnitudes have been equivalent to strong earthquakes, ranging from M4.9 to M5.3. Experts claim there are wave patterns typical of nuclear tests, and this helps distinguish them from natural earthquakes.

　6. So far, there may be no direct proof or scientific research pointing out that nuclear devices detonated in underground test sites in North Korea do cause earthquakes and tremors in the region.

　However, one cannot help but notice a close sequence in earthquakes recorded in South Korea and in Japan, hinting at a possible co-relationship, especially following the 5th nuclear test of September, 2016, and it is hard to imagine how strong seismic waves from North Korea could be harmless or without geological repercussions in terms of causing underground shifts, slippage and other movements, especially along fault-lines.

　Moreover, no one can deny the fact that the shockwaves caused by the underground explosions must have eventually reached the different points on earth where they were detected and recorded in observatories.

(Note) One may recall the conclusions reached by Edward Lorenz by computer simulation in the early 1960’s that, seemingly minute changes in initial conditions may eventually bring on unexpectedly large differences, in systems such as the weather. This was termed the “butterfly effect” in the chaos theory, suggesting that the mere flap of a butterfly’s wings could eventually cause tornadoes in the end.

　7. Silicon Graphics has discussed the issue of such causation on the internet, as follows:

(1) An underground nuclear test was conducted in Nevada on June 19, 1992, and another test was conducted only 4 days afterwards. 3 days later, a series of earthquakes as strong as 7.6 on the Richter scale rocked the Mojave Desert 176 miles to the south, and they were the biggest earthquakes to hit California until then in the 20th century. 22 hours later, an earthquake of 5.6 struck less than 20 miles from the Nevada test site itself, the biggest quake ever to be recorded near the test site.

　 In response to public concerns, the US Department of Energy issued a statement on July 14 that year, asserting that the relationship between nuclear testing and earthquakes was “nonexistent.”

(2) 2 Japanese scientists, S. Matsumae and Y. Kato of Tokai University conducted a study 20 years later and concluded as follows:

　Abnormal meteorological phenomena, earthquakes and fluctuations of the earth’s axis are related in a direct cause and effect (relationship) to testing of nuclear devices…Nuclear testing is the cause of abnormal motion of the earth. By applying the dates of nuclear tests with a force of more than 150 kilotons, we found it obvious that the position of the pole slid radically at the time of the nuclear explosion…Some of the sudden changes measured up to 1 meter in distance.

　8. The shockwaves from large earthquakes have been known to travel over very long distances and cause tremors and fluctuations in unexpected places.

(1) The Great East Japan Earthquake of March 11, 2011 triggered sudden strong “seiche” waves the same day, in the Aurland-Flam fjord in Norway, and these measured up to 1.5~2 meters from trough to crest.

　Historically, there are records that the great 1755 Lisbon earthquake unleashed seiches in the fjords, and the last earthquake to set off seiches in Norway’s fjords was apparently the M8.6 Assam earthquake of 1950 in Tibet.

(2) On May 24, 2013, the M8.3 Okhotsk Sea earthquake occurred, and the tremors could be felt in places as distant as Tokyo, Nanjing and Moscow, where almost 900 residents left their homes to seek shelter.

　9. In 2016, North Korea conducted 2 underground nuclear tests, and given the earthquakes that did closely follow on, South Korea and perhaps Japan may be sufficiently motivated to try to find out if there may indeed be a logical correlation or cause-and-effect relationship between underground nuclear tests in North Korea and such earthquakes. China and Russia may also be given to similar concerns.

　10. The important points should be as follows:

(1) In the past tense, could the string of nuclear tests in North Korea have caused seismic ripples throughout the Korean Peninsula and across the Sea of Japan in close succession, accumulating stress and pressure over time, starting real earthquakes that otherwise might not have happened, including in unusual places?

(2) For the future, if North Korea were to conduct another nuclear test, would that not trigger new earthquakes, causing more damage, displaced persons and possibly, casualties?

(3) Furthermore, even if underground nuclear tests were not powerful enough to cause large, cataclysmic earthquakes that bring on heavy damage or casualties per se, they could play the role of the last straw, and trigger a large earthquake that otherwise may not have occurred at that particular location and at that point in time, i.e. to cause the seismic event to occur well ahead of “schedule,” by jerking forward the natural process by which geological stress accumulates, normally over years and decades.

　11. In any case, given the increasing number of earthquakes in the region in the 21st century, including in unusual places, North Korea would do well to recognize the strong effects of climate change, and halt nuclear tests as a safety measure, to ensure that geological disturbances are kept at a minimum, and that none are caused by human activity.

　This could be done without needlessly waiting for scientific proof of seismic linkages that could be time-consuming, because the shockwaves caused by underground explosions are far-reaching, as attested by the observatories in different countries that have detected and recorded them.

　12. Furthermore, following the Fukushima nuclear crisis concomitant with the Great Tohoku Earthquake in 2011, there is a strong public awareness that the safety of nuclear power generators is much dependent on the stability of the terrain, especially in earthquake-prone countries such as Japan.

　Since then, there has been a process of scrutiny to ascertain the safety of nuclear power plants throughout Japan, shutting them down, albeit temporarily, to check upon their safety environment, and decisions on re-opening are largely dependent on the result of geological surveys on the terrain and conditions underground where they operate.

　If underground nuclear tests conducted by North Korea can cause real earthquakes, including in places where natural earthquakes are considered rare, the credibility and reliability of such geological surveys will be put to question, and the safety of nuclear power generators must be seen in a completely different light, with added factors of uncertainty coming from North Korea.

　13. In this context, South Korea and other neighboring countries may need to consider making strong, concerted representations against North Korea, so that it may decide to stop such underground nuclear tests immediately for humanitarian reasons, in the interests of protecting citizens and their livelihood, including those living in North Korea itself.

　14. Besides the long term military implications of North Korean nuclear tests on the national security of potential opponents from the days of the Korean War, a priority concern on the basis of the above reasoning must involve the factor of predictability.

　That is to say, if underground nuclear tests can bring on earthquakes that cause real damage and casualties, an obvious conclusion is that North Korea should give a clear forewarning well before such a test is actually conducted, announcing the exact date and timing as well as expected magnitude, so as to enable nations in the immediate vicinity to be on the alert and take steps to minimize the consequences.

　To go ahead with an underground nuclear test without making such a public announcement in advance should be considered a gross act of negligence whilst knowing the possible consequences for the neighbors, and should be avoided at all cost.

　15. The succession of earthquakes in East Asia in 2016, regardless of whether or not they followed on North Korean nuclear tests by sheer coincidence, has served as a reminder that there is a close-knit geographical, geological and environmental relationship among countries in East Asia, including North Korea, South Korea, Japan, China and Russia, which all rest on the Eurasian tectonic plate.

　This may provide the needed window of opportunity for renewed dialogue with North Korea, to seek peaceful means of resolving differences, as there used to exist in the framework of the 6 Party talks.

　16. Ironically enough, the testing of nuclear weapons has been driven underground, following adoption and coming into force of the Partial Nuclear Test Ban Treaty in 1963, spearheaded by the US, UK and the Soviet Union.

　The aim of this treaty was to limit the effects of massive radioactive fallout from nuclear tests by banning them from the atmosphere and stratosphere as well in the waters; in conclusion, tests were to be conducted underground, as they were considered less harmful in this regard. The last tests were conducted underground by India and Pakistan in 1998, until North Korea started its own underground tests in 2006.

　The Comprehensive Nuclear-Test-Ban Treaty was adopted in 1996, but has not come into force, as the conditions requiring ratification by the nuclear weapons states and 44 others have yet to be fulfilled.

　If a case can be made against underground nuclear tests on grounds that they could cause subsequent “natural” earthquakes, there may be an urgent need to outlaw them as well, and the CTBTO Preparatory Commission may have an additional and convincing argument to promote their cause.

　17. Chronology

　1978 Only 5 tremors observed in South Korea.

　1980.1 Earthquake of maximum intensity 5.3 occurs in North Korea.

　 (Historically, the largest to be observed by the

　South Korean Meteorological Agency.)

　1995.1 Hanshin-Awaji Great Earthquake in Japan,

　reaching intensity 7.0.

　2000.10 Earthquake in west Tottori Prefecture, reaching intensity 7.3.

　2004.5 Earthquake of maximum intensity 5.2 in South Korea.

　2004.10 Chuetsu Earthquake of intensity 6.8~7.0 in Niigata, Japan.

　2005.3 Ripples from earthquake in Fukuoka, Japan,

　reach Busan, South Korea.

　2006.10 North Korea conducts 1st nuclear test.

(M 4.9, according to Japanese sources.)

　2006.11 Earthquake off the coast of the Kurile Islands (M8.2)

　2007.1 Earthquake off the coast of the Kurile Islands

　 (Outer rise from the Japan Trench, M8.1)

　2007.1 Earthquake of maximum intensity 4.8 in South Korea,

　close to North Korean border.

　2007.3 Earthquake in Noto Peninsula, Japan, M6.9

　2008.6 Earthquake in Iwate and Miyagi, Japan, maximum intensity 6.0.

　2009.5 North Korea conducts 2nd nuclear test. (M5.3)

(In 2009, more than 80 tremors are felt in South Korea.)

　2010.2 Earthquake of maximum intensity 3.0 to the west of Seoul

　2011.3 Great Tohoku Earthquake hits Japan.

　2013.2 North Korea conducts 3rd nuclear test. (M5.1)

　2013.5 Okhotsk Sea Earthquake (M8.3)

　2016

　1.6 North Korea conducts 4th nuclear test.

(M 5.1, as detected in Japan.)

　1.11 Earthquake in Rumoi, Hokkaido (Max Intensity 4, M6.2)

　1.14 Earthquake off Shizunai, Hokkaido (Max Intensity 6, M6.7)

　2.6 Earthquake in Tainan City, Taiwan (Max Intensity 7, M6.4)

　4.13 Earthquake northwest of Siocon, Philippines

　 (Max Intensity 7, M6.0)

　4.14~15 Kumamoto Earthquake in Japan (Max Intensity 8~9, M6.0~7.0) causes death of 110 inhabitants.

　5.31 Earthquake offshore Taiwan (Max Intensity 4, M6.4)

　8.4. Offshore Japan, near Iwo Jima (Max Intensity 2, M6.3)

　8.20 2 earthquakes offshore Japan near Iwate Prefecture

　 (Max Intensity 4, M6.0)

　9.9 North Korea conducts 5th nuclear test, (M 5.3)

　9.12 Earthquake hits South Korea (Max Intensity 7, M5.8)

　 Strongest recorded earthquake in South Korea.

　9.20 Offshore Hachijo-jima, Japan (Max Intensity 3, M6.1)

　9.23 Offshore Chiba Prefecture, Japan (Max Intensity 4, M6.2)

　9.24 Davao Oriental, Philippines (Max Intensity 5, M6.3)

　9.26 Near Nago, Okinawa Prefecture, Japan (Max Intensity 5, M6.0)

　10.21 Earthquake hits Tottori, Japan (Max Intensity 8, M6.2)

　 400 people are forced to flee their homes.

(2017)

　9.3 North Korea conducts 6th nuclear test, claims successful test of hydrogen bomb. (M6.3)

(Notes)

　1. “Intensity” is a measurement that indicates the strength of local tremors as felt by humans; “magnitude” (M) is a measure of the total amount of energy released in an earthquake.

　2. Maximum intensity and magnitude depicted above are according to open sources including news reports. The figures tend to differ according to the place of observation, and may need to be checked and augmented.

　3. In Japan, the Eurasian and the North American tectonic plates meet in the middle of Honshu Island, so that the boundary runs roughly along the Japanese Alps, from the Sea of Japan to the Pacific Ocean. Hokkaido and the northwestern part of Honshu including Chiba Prefecture are on the North American plate, whereas the Kansai area including Kumamoto and Tottori are on the Eurasian plate.

　4. Taiwan, where earthquakes used to be rare, is also on the Eurasian plate, as is the Philippines and other countries in southeast Asia, especially the ASEAN member states, not to speak of China and Russia.