A Thousand Tiny Quakes: Documenting Russian Bombings in New Detail

The explosions came one after another, a relentless series of bombings that echoed across Kyiv in the first weeks of the war. Residents at the center of Russia’s invasion of Ukraine were forced underground into makeshift shelters.

While the fight for Ukraine’s capital is well known, researchers have developed a new tool to systematically document Russian attacks by using one of the most universal elements of the battlefield: the explosions that shook the earth.

Seismic waves were generated when Russia fired artillery, airstrikes and missiles across northern Ukraine. For the first time, researchers in Norway and Ukraine studied data from dozens of earthquake sensors around Kyiv, estimating the position and strength of each explosion to see the full extent of the Russian barrage.

There is no perfect way to chronicle a war, and the seismic record has gaps. Attacks farther from the sensors are most likely to be missed. A few of the explosions may have been set off by Ukraine. And the unique geology of the city of Kyiv, built on wetlands and floodplains, deadens signals from explosions, researchers say.

But unlike the selective focus of traditional war reporting, seismic detections can track blasts at any time, picking up hundreds of attacks that were not previously reported. And the objective measurements can see through the distortions of social media reports and aggressive propaganda from both sides.

“It’s a way of finding out what’s happened which doesn’t involve anecdotal reports,” said Ben Dando, a seismologist at NORSAR, an independent research foundation in Norway and the lead author of a paper on the work published today in the journal Nature. “It’s verifiable data that’s showing what happened where.”

One well-known attack illustrates how the detection works.

On the fourth day of the war, an explosion was detected at the Hostomel airport outside Kyiv. Satellite imagery from the same day showed smoke billowing out of one of the hangars.

The force from the explosion sent seismic waves toward two dozen nearby sensors, the equivalent of a tiny 0.2-magnitude earthquake.

This bombing was one of more than a thousand detected explosions during a constant, around-the-clock barrage during the first five weeks of the war.

As Russia’s attempt to capture Kyiv failed and its troops withdrew from northern Ukraine in early April, the rate of the bombardments dropped. But Russia continued to bomb civilian infrastructure, hitting the Malyn train station in the early morning of May 20 and injuring three people. The researchers said that they picked up three separate explosions from the attack.

Militaries have long used remote sensing techniques to detect missile launches, bombings and other details of conflict. But their records are largely kept secret, and the researchers said public research on seismic detections of conventional weaponry is lacking.

Using the same technique in future conflicts could help document wartime violations of human rights, said Sebastian Schutte, a senior researcher at Peace Research Institute Oslo who has used spatial data to research conflicts around the world. For example, he said, it could be used to document “double tap” strikes in which an attack on a civilian area is followed, after a delay, by a second attack aimed at rescue workers.

Dr. Schutte said the data could also guide post-war cleanup efforts, as areas that experience large numbers of blasts inevitably contain unexploded munitions, “which oftentimes kill civilians for decades to come.”

Keith Koper, a professor of geology and geophysics at the University of Utah and the director of its earthquake observatory, who reviewed the analysis, said the work appeared to be “careful and rigorous.” But although there are hundreds of seismic arrays around the world, few war zones have high-quality arrays, he said.

“It is a very unusual situation. There was nothing similar in Iraq or Afghanistan, for instance,” Professor Koper said.

Researchers determined the location of a blast to within a couple of miles by analyzing the timing of multiple seismic waves that arrived at each sensor after the blast went off. They also estimated the size of each blast, although this was more of a rough estimate.

Dr. Schutte said that the current approach for using seismic waves to monitor wars had limitations, because it required “a large-scale array that happens to sit in a war zone. More research is needed to make this an easily deployable solution.”

“But the glass is way more than half full here,” he said. “The first telescopes, satellites, and radars could not see much, but they all sparked decades and centuries of steady progress and now deliver invaluable data. Let’s hope this approach will also be developed over time to reveal intentional attacks on civilians, and thereby deter perpetrators.”