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.
