Anak Krakatau: Spectacular Video Shows Volcano Generating Its Own Lightning During Eruption

A spectacular video has emerged online of the Indonesian volcano Anak Krakatau, spewing out lava bombs and plumes of ash as lightning appears to emanate from the crater.

The incredible footage was captured by researcher Richard Roscoe from a nearby island during eruptions in October.

"In the first sequence, glowing volcanic bombs can be seen setting fire to vegetation and causes large splashes as they fall into the sea around the Anak Krakatau Island," Roscoe wrote in his YouTube post. "Probably due to a change in ash characteristics, eruptions were suddenly accompanied by numerous static discharges, also known as volcanic lightning."

Anak Krakatau is notable for being the currently active part of the famous volcanic island Krakatau (or Krakatoa)—which experienced a cataclysmic eruption in 1883. This event was one of the most destructive volcanic events in recorded history, with at least 36,147 deaths attributed to the eruption and related tsunami.

The eruption was so powerful it darkened the sky for years afterward and had a significant impact on the world climate. The following year, for example, global average temperatures fell by as much as 2.2 degrees Fahrenheit.

Furthermore, the eruption destroyed 70 percent of the island and its surrounding archipelago as it collapsed into a caldera—large volcanic crater. Anuk Krakatau emerged as a new island from this caldera in 1927 and is now the current location of eruptive activity. In fact, its name means "Child" or "Son of Krakatoa."

Lightning discharges, such as those seen in the video footage, are often observed during explosive volcanic eruptions and are commonly associated with the formation of ash plumes, according to the United States Geological Survey (USGS).

In order for lightning to form like this there needs to be a large charge separation between two masses, according to Oregon State University (OSU).

"If the charge separation becomes big enough it is then able to overpower the air resistance, create a path of ionized air, and conduct electricity in the form of lightning," according to the university's Volcano World outreach project.

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Lava streams down from Anak Krakatau during an eruption as seen from Rakata island in South Lampung on July 19, 2018. FERDI AWED/AFP/Getty Images

"The ash that is to be erupted begins as electrostatically neutral rock or rock fragments. Heat and movement within the volcano is thought to be the first source of particle charging, although the main process by which ash particles acquire a charge is friction," OSU wrote. "When an object (in this case ash) with a neutral charge comes in contact with another object with differing electrostatic qualities, electrons can potentially flow and one of the objects can become charged relative to the other. "

Despite being less than a century old, Anuk Krakatau is of considerable interest to volcanologists and has been extensively studied, not least because of its spectacular eruptions.

Anak Krakatau: Spectacular Video Shows Volcano Generating Its Own Lightning During Eruption | Tech & Science