The battle between Trump and political establishment is underway. The outcome of this intriguing process will answer the question who is Mr Trump - a system failure or an indication of failed system.
The current discussion between G6 and USA reveals the fact that there is only one country among 7 which really takes decision. Trump is not happy with G6 because they are trying just to limit his capability to take decisions. This is worthless and time consuming. Instead, he tries to meet with other decision takers, i.e. Russia and China. They demonstrate that they can take decision and be responsible for them. hence, the best future format to resolve real problems is G3. EU is helpless by design.
Discrimination of the DPRK underground explosions and their aftershocks using the P/S spectral amplitude ratio
We have estimated the performance of discrimination criterion based on the P/S spectral amplitude ratios obtained from six underground tests conducted by the DPRK since October 2006 and six aftershocks induced by the last two explosions. Two aftershocks were detected in routine processing at the IDC. Three aftershocks were detected by a prototype waveform cross correlation procedure with explosions as master events, and one aftershock was found with the aftershocks as master event. Two seismic arrays USRK and KSRS of the IMS and two non-IMS 3-C stations SEHB (South Korea) and MDJ (China) were used. With increasing frequency, all stations demonstrate approximately the same level of deviation between the Pg/Lg spectral amplitude ratios belonging to the DPRK explosions and their aftershocks. For a single station, simple statistical estimates show that the probability of any of six aftershocks not to be a sample from the explosion population is larger than 99.996% at the KSRS and even larger at USRK. The probability of any of the DPRK explosion to be a representative of the aftershock population is extremely small as defined by the distance of 20 and more standard deviations to the mean explosion Pg/Lg value. For network discrimination, we use the Mahalanobis distance combining the Pg/Lg estimates at three stations: USRK, KSRS and MDJ. At frequencies above 4 Hz, the (squared) Mahalanobis distance, D2, between the populations of explosions and aftershocks is larger than 100. In the frequency band between 6 and 12 Hz at USRK, the aftershocks distance from the average explosion D2>21,000. Statistically, the probability to confuse explosions and aftershocks is negligible. These discrimination results are related only to the aftershocks of the DPRK tests and cannot be directly extrapolated to the population of tectonic earthquakes in the same area
Seismic stations in South Korea, China and Russia detected increasing aftershock activity within the mountain where the biggest DPRK nuclear test was conducted on September 3, 2017. A few aftershock events occur three months after the test and about two months after the previous aftershock on October 12. This activity might be related to a complete collapse of the mountain or chimney collapse with opening of a direct access from the explosion cavity filled with radioactive debris to the atmosphere. This is the worst case scenario, but one cannot exclude this effect especially in view of high international tension in this region. China, Russia and South Korea are just in tens of kilometers from the test site, and Japan is not too far away. Seismologists continue detailed study without interruption and delay.
I guess that all current problems, clashes and overall turbulence, even if everything goes wrong way, will not be any important part of political/social/private life in 25 years. There are fierce discussions (even small wars) of most sensitive local/regional/global issues between great, not so great and small countries and organizations. It seems so much important to us. However, historically speaking this is just noise. People do not consider Nazism and concentration camps as a part of everyday lives any more. It is just sad history to remember to the date and it should not happen again, if possible. This was by far the worst crime against humanity.
The Democratic People's Republic of Korea (DPRK) conducted 6 underground test, with the last 5 from 6 in the same mountain. The biggest (sixth) event conducted on September 3, 2017 (DPRK6) had magnitude (mb=6) and resulted in visible landslides and also was followed by a few aftershocks with magnitudes between 2.4 and 3.4. Two of them occurred on September 23 (around 4:40 and 8:30 UTC) and are likely were reported today as the cause tunnel collapse and casualties. The test conducted on September 9, 2016 was also followed by a small aftershock well described in our paper (https://arxiv.org/abs/1611.03055 or https://link.springer.com/article/10.1134/S1028334X17030011 ), which is very similar to the aftershocks of the DPRK6.
Among many challenges in the analysis of various physical measurements related to the DPRK test is the absence of measurable levels of radioactivity after 4 from 6 events and just minor traces of radioactivity after the other two. Very deep placement of warheads can prevent radioactive gas venting and thus provide effective containment of radioactive debris, Let's consider two possibilities alternative to nuclear testing.
Having the last event equivalent to about 100,000 tons of TNT, one can reject the hypothesis that this DPRK test was a chemical blast. An alternative explanation would be testing of tectonic weapon, as introduced by Russian geophysicist V. Nikolayev in 1992. There are several physical mechanisms that can be used to facilitate effective release of pre-existing tectonic energy and generation of seismic waves. In any case, the mountain is exhausted after five tests and no more tectonic release is possible. I do not believe that tectonic weapon can be as efficient as we observed in six DPRK events. In case it does exist this is an additional threat for the peaceful world.