The crater Tjarnargígur or “Pond Crater” is one of many craters created in the infamous 1783-1784 eruption Skaftáreldar in Iceland. Nearby places: Laki, Langisjór, Eldgjá
The eruption is thought to have played a significant role in causing a famine in France which was one of the main causes for the french revolution.
For those interested you can read more about that in this article from Guardian: https://www.theguardian.com/…/iceland-volcano-weather-frenc… Lakagígar is a volcanic fissure in the south of Iceland, not far from the volcanic fissure of Eldgjá and the small village of Kirkjubæjarklaustur.
The system erupted violently over an eight-month period between June 1783 and February 1784 from the Laki fissure and the adjoining volcano Grímsvötn, pouring out an estimated 42 billion tons or 14 km3 (3.4 cu miles) of basalt lava and clouds of poisonous hydrofluoric acid and sulfur dioxide compounds that contaminated the soil, leading to the death of over 50% of Iceland’s livestock population, and the destruction of the vast majority of all crops.
This led to a famine which then killed approximately 25% of the island’s human population. The lava flows also destroyed 20 villages. The Laki eruption and its aftermath caused a drop in global temperatures, as 120 million tons of sulfur dioxide was spewed into the Northern Hemisphere. This caused crop failures in Europe and may have caused droughts in North Africa and India.