Certainly huge volcano eruptions in Revelation can easily produce those events, darkness, blood moons etc...
have happened before...
look at the results in the 1815 and 1880s eruptions in the East Indies.... Krakatoa East of Java 1880 something... great PBS video on u tube...

the 1815 eruption created a year without a summer, darkness in New England and elsewhere Snow in mid summer........ So my money is on a volcanic super eruption somewhere causing Revelations darkness and blood moons...
there are several Yellowstone type super volcanoes around the Earth...
And the massive Middle East quakes could cause such an eruption there around the Gog Magog war time frame

 

Lewis B