The Welsh Colonisation of Patagonia: a Volcanic Connection.
This was the most powerful volcanic explosion in recorded history, and the ash was carried so far into the atmosphere that it screened the earth from the warmth of the sun. The next year, 1816, was so cold that it was known as the year without a summer. For several years crops failed and food became expensive. The poor became poorer, a situation exacerbated by the potato blight a few decades later. Everyone suffered, but the Welsh soon had special grievances in the form of English taxes imposed by English land lords and English clergy. There were numerous waves of protests, and Karl Marx noted that the Welsh were ripe for rebellion.
The final trigger, though, came from a school inspection and the conclusion that the Welsh language was not fit for modern life. It caused the disquiet to grow, and from north Wales came the first murmurings of a radical proposal: why not go somewhere so remote the English would not have a chance to interfere?
The land they were about to inhabit would owe its existence to volcanoes too. The soils of the Chubut valley have been made fertile (in part) by the pale tuffs of old volcanic explosions swept to the valley by the prevailing wind from the Andes. And their final settlement, Esquel, is still periodically threatened by volcanic ashes. The last time was just last year when the Puehue-Cordon Caulle volcanic complex erupted in Chile.
So one volcanic explosion indirectly caused the Welsh to flee into the path of another. The events are separated by many years, but it interests me how geology and the fate of this population of people are connected.