The deadly Beirut explosion caused electrical disturbances in the Earth’s ionosphere – part of our planet’s upper atmosphere ionised by solar radiation – just like past volcanic eruptions, a new study published in Scientific Reports found.

A team of scientists from Hokkaido University in Japan, joined by colleagues from the National Institute of Technology Rourkela, studied changes in the electron content of the ionosphere, which spans around 48-965 km in altitude.

"We found that the blast generated a wave that traveled in the ionosphere in a southwards direction at a velocity of around 0.8 km per second," scientist Kosuke Heki said.

The findings came to light after the researchers calculated differences in microwave transmission phases sent through the Global Navigation Satellite System on 4 August, when the explosion took place. When signals pass through the Earth’s upper atmosphere they are affected by its electron content, meaning that any disturbances resulting from volcanic eruptions or nuclear testing can be easily detected with the help of GPS signals.

The scientists also compared the Beirut explosion to the impact of multiple anthropogenic events and natural disasters, including Japan’s Asama Volcano eruption in 2004. They concluded that Lebanon’s tragedy made a larger impact on the Earth’s atmosphere compared to the Asama event. When reviewing the man-made explosion in America’s Wyoming coal mine in 1996, the team found that the Beirut blast was weaker in terms of power – equivalent to the detonation of 1.1 kilotons of TNT in Lebanon to 1.5 kilotons in the US. Still, the 4 August 2020 explosion caused a much larger electron content disturbance, potentially due to the blast’s greater exposure to the planet’s surface in comparison to the coal mine blast.

The Beirut explosion killed hundreds of people and destroyed many buildings, leaving scores of people homeless. The blast, that was also felt in neighbouring countries, was caused by the detonation of ammonium nitrate unsafely stored in port warehouse.