Lights associated with earthquakes?
I am not too much into the subject, but it is a curious phenomenon indeed.
There is a recent publication in Scientific Reports (Enomoto et al., 2017) where a group of scientists performed some lab experiments and reported:


  CO2 gases passing through the newly created fracture surface of the rock were electrified to generate pressure-impressed current/electric dipoles, which could induce a magnetic field following Biot-Savart’s law, decrease the atmospheric electric field and generate dielectric-barrier discharge lightning affected by the coupling effect between the seismic and meteorological activities


If you want to read the full paper you can search it with this reference: 

Enomoto, Y., Yamabe, T., &amp; Okumura, N. (2017). Causal mechanisms of seismo-EM phenomena during the 1965–1967 Matsushiro earthquake swarm. Scientific Reports, 7. doi: 10.1038/srep44774.

It is open access.