AH challenge, Volcanism era.

AH challenge. Survival and prosperity under increased volcanism

We posit that the Krakatoa eruption of 1883 was not only much, much larger but the beginning of a volcanic age on the Earth, with an ongoing level of activity equivalent to that of the Deccan Traps era

Krakatoa erupts Supervolcano style, so does Yelllowstone and Fujiyama. In Europe we have Vesuvius as a normal eruption but still very big, also Kilimanjaro in Africa and several others. Big Tsumanis most everywhere, years without summers etc. etc.

This abates, but continues with much increased volcanism and earthquakes over the whole earth. The Appalachians (for god knows what reason) begin to rise again.

The challenge is to make humanity survive and prosper in this environment to the present day. It doesn't have to have the same level of tech or standard of living as now but it shouldn't be amazingly backward either (mid 19thc or thereabouts with mods.) You may have large patches where civilization is backward or gone but at least 3/8 of the Earth's habitable surface should be in a recovered and ongoing state.

Given where you said the volcanos were in terms of latitude, the equator and northern hermisphere will be totally screwed for growing seasons for decades. Blown ash will stay in the air, block out sunlight, cause killing frosts in the summertime.

All civilization there will crash, and the people left will be hunter-gatherers, assuming the ecosystem in general doesn't crash, which it very well might, as the decreased light will lead to less plant growth and algae, which will cause stress up and down the entire food chain, quite possibly mass extinctions

I would say Argentina/Chile, Australia, and South Africa are likely the only places something resembling civilization could survive, as they are far enough removed from the bands the volcanic dust is in that some semblance of normality may remain. They are isolated enough that refugees may swamp them as well. But there is no way I could see any states surviving north of that.