Question: What is the hottest volcano that has ever been recorded in the 21st/20th century?

Natasha Dowey answered on 4 Mar 2019:

Oooo good question!
Most lavas range from about 700 degrees to about 1400 degrees celcius, which is incredibly hot. It’s all to do with the chemistry of the lava and its melting point. It’s generally accepted that lavas rich in iron and magnesium tend to have hottest lavas, because this magma has a high melting point (like the Hawaiian volcano lavas- the USGS has this nice bullet point list about their temperatures: https://www.usgs.gov/faqs/how-hot-a-hawaiian-volcano?qt-news_science_products=0#qt-news_science_products).
There’s actually been a study on how hot volcanoes are, carried out using data from NASA satellites- it found that Hawaii is the hottest volcano in the world, in terms of the total heat energy it has radiated. It also found that the hottest single eruption event in recent years was one in Iceland called Holuhraun in 2014. This article talks a bit more about it and has a cool video in it of scientists sampling lavas at Holuhraun: https://earthsky.org/earth/hawaiis-kilauea-volcano-ranks-as-hottest