According to Quantum FFF Theory, Black hole nuclei are not able to show inertial rotational oscillation strain in a merger process.
Recent LIGO Neutron merger signals show also a reduced comparable effect.
See also: https://www.scientificamerican.com/article/gravitational-waves-reveal-the-hearts-of-neutron-stars1/According to Quantum FFF Theory, Black Holes have no inertial mass, due to their non Baryonic Dark Matter Axion/Higgs content, (then no rotational strain but only nuclear particle oscillation-tension effects will take place during merging.
Black Hole merging without rotation oscillation, due to massless BH Inertia absence, according to Quantum FFF Theory. (=duration about 1 sec.)
Neutron stars however have normal baryonic mass and consequently rotational based strain effects. (=duration about 30 sec )
The difference in duration (30 sec.to 1 sec.) is supposed to be originated by the fast transformation of massive Neutrons into massless Axion Higgs nuclear particles of the newly formed black hole during the merging process..
see also:
https://www.researchgate.net/publication/324497489_Dark_Matter_Black_Hole_Galaxy_Hierarchy_according_to_Quantum_FFF_Theory
Ball lightning could be described as the smallest Axion-Higgs based electric dark matter black hole ( or rigid string based quantum knot) with an external negative charge. (below)
For micro electric dark matter black holes or ball lightning, originated by X-ray or Em interference in silicon crystals: http://vixra.org/pdf/1302.0172v3.pdf
