The eruption of Japan's Sakurajima volcano caused a huge ash cloud and volcanic lightning. The result was the extraordinary time-lapse above.

Electrical discharges during volcanic eruptions are not uncommon and are known as volcanic lightning. However, it does not always result in as many discharges, particularly in the amount observed above.

However, it is normal for volcanic lightning to discharge in the ash plume of a volcanic eruption. Only occasionally do they actually shoot out of the ash plume. This happened, for example, in the March and June of 2023 at the Fuego volcano in Guatemala.

The cause of volcanic lightning in the ash cloud is friction between the finest ash and dust particles, which shoot out of the volcano's crater during an eruption under high pressure.

In the process, the particles become electrically charged, which then causes the discharge of energy. Although this doesn't occur in every volcanic eruption, their frequency increases with the strength and explosiveness of an eruption.

Volcanic lightning was also observed during the massive eruption of the Tonga volcano on January 15th 2022. At that time, hundreds of thousands of lightning bolts were recorded in ash clouds up to 58 km high. This eruption is considered one of the most powerful in recent history.

Sakurajima is a stratovolcano located in the far south of Japan, about 8 km from the city of Kagoshima. The volcano is among the most active volcanoes on Earth and often has hundreds of smaller and larger eruptions per year.

The volcano is so active due to its location on the Pacific Ring of Fire. This is the most geologically active zone on Earth. Earthquakes and volcanic eruptions are particularly frequent there.

Usually the Japanese volcano only causes inconvenience by ash as it gets rained out, but in 1914 it also caused casualties. Incidentally, these were caused by the heavy earthquake that preceded the eruption, but the population was fortunately evacuated before the actual eruption.