Video from an active volcano in Japan earlier this month shows incredible eruptions of lava and ash laced with volcanic lightning.

“Shot by filmmaker Marc Szeglat, 47, this incredible footage shows the highly active Sakurajima volcano on the Japanese island of Kyushu,” says the Barcroft TV YouTube page. “The German videographer was able to capture the rare phenomenon of volcanic lightning, as well as an explosive shockwave which rippled through the sky.”

Lightning in volcanic eruptions is caused by the same reason it occurs in thunderstorms — negative and positive charges separate in the atmosphere, and lightning is what restores the charges to balance. But why the charge separation occurs in volcanic eruptions in the first place is still not well-understood. There seem to be a few theories, including one that suggests the ash ejected from the volcano already carries a certain charge, which then interacts with the charges in the atmosphere.

Volcanic lightning is difficult to capture — it usually only happens in the most intense eruptions, and is often confined to the very beginning of the eruption. While these are two of the hottest surfaces on Earth, lightning — at an astonishing 50,000 degrees Fahrenheit — is actually 25 times hotter than lava.

The volcano Sakurajima is located in southern Japan in the Kagoshima Prefecture. “Although Japan’s Sakura-jima volcano is one of the most active in the world, it rarely makes headlines,” says NASA in a story on the volcano in 2013. “One or two small explosions typically occur every few days, with effects no greater than a light dusting of ash on the surrounding cities.”