Interesting research Saul. I had not previously really appreciated this phenomenon, I think this field of research is most active in the Far East. I'm guessing "Benioff electromagnetic radiation" (the term used in the first reference) is the technical term for "earthquake lightning" (the term used in the second reference)?
If they are the same thing then it seems we have two proposed mechanisms for generating the electromagnetic radiation: (1) due to electric discharge by dielectric breakdown of ambient gases from friction contacts between rock minerals, and (2) Change in seismic stress releases piezo-compensating, bound charges due to changes in the piezoelectric polarization of quartz grains in granitic rocks. I would expect that both mechanisms are at play but it would be interesting to know which is the dominant -- clearly this would be dependent on geology as you would need the right mix of gases for the first, and sufficient quantities of quartz for the second. Of course, there is probably a third mechanism that has been overlooked here.
Note that in both these papers the electromagnetic radiation is in response to changes in the stress. Those changes in stress are also the cause of the earthquake (the rocks want to be in equilibrium just like pretty much everything else in physics, if you put a load on them that they are not strong enough to support then they will adjust to find a more stable equilibrium, when that happens suddenly and releases a lot of energy then we call that an earthquake). So, to be clear, this research does not propose a mechanism for triggering earthquakes electromagnetically. Rather, these papers propose physical mechanisms for explaining the cause of electromagnetic radiation which we observe to precede earthquakes. (I'm not 100% certain on the strength of the link between electromagnetic anomalies and earthquakes however, we must be careful that these observations are not coincidental magnetic storms which are pretty common -- is there something characteristic about this electromagnetic energy? Has it been observed frequently enough to confirm the link on statistical grounds?) I agree with Saul that it is at least plausible, if not likely, that animals respond strangely to this electromagnetic radiation -- if there is some data which shows the relative timing of the events this hypothesis would be easily falsified if animals were seen to react strangely before the onset of anomalous electromagnetic activity. However, again, I would question why animals aren't observed to behave strangely during magnetic storms -- which makes me wonder if there is a characteristic frequency of the earthquake precursor electromagetic energy.