Seismic Station Detected Possible Blast During Baltic Gas Line Breach

Baltic Connector seismic location
Location of the faint seismic event in the Gulf of Finland early Sunday morning (Illustration courtesy NORSAR)

Published Oct 11, 2023 10:40 PM by The Maritime Executive

A sensitive seismological array in Finland picked up a signal at the time that the Balticconnector gas pipeline ruptured last weekend, according to scientific consortium NORSAR. However, the magnitude was below the typical level of detection, equivalent to less than 100 kilos of TNT - far less than the massive blasts detected during the Nord Stream sabotage attack last year. 

NORSAR's stations picked up seismic waves indicating a "possible explosion" at 0120 hours on October 8, originating near the coast of Finland. The magnitude was low, about 1 on the Richter scale, and the findings are not conclusive: NORSAR left open the possibility that the faint signal could have been caused by either sudden rupturing of the pipeline and a release of gas, or by detonation of explosives. 

The findings of a physical inspection of the pipeline suggest that external, mechanical force may have been the cause. Estonia's defense minister, Hanno Pevkur, told Reuters Tuesday that "mechanical impact or mechanical destruction" could have caused the damage, and that "quite heavy force" was required. 

The pipeline was encased in concrete, and the casing "has broken, or peeled off, specifically at that point of injury," Estonian Navy Cmdr. Juri Saska told Estonia's public broadcaster. The appearance of the damage suggests "someone tore it on the side," he said. 

Analysts have turned to AIS data to determine whether there were any suspicious vessel movements around the time of the breach. There were four ships in the general area, according to Estonia's vessel traffic management agency, including one that was anchored for two days - the aging Russian ore-bulk-oil carrier SGV Flot (IMO 8033089). Her St. Petersburg-based operator confirmed that she had been nearby, but said that the ship was simply waiting on the hook for better weather. A storm system was blowing through the area over the weekend. 

After the massive attack on the Nord Stream pipeline complex last year, defense officials in Estonia, Finland and allied NATO nations are looking closely at the possibility that it was an act of sabotage. As recently as April, Russia threatened to take "military-technical" measures against Finland as a penalty for its decision to join NATO. 

Charly Salonius-Pasternak, researcher at the Finnish Institute for Foreign Policy, told German outlet Tagesschau that "the list of states in the region that have the opportunity, motive and ability to carry out something like this is quite short. There's only Russia."

On Tuesday, NATO Secretary General Jens Stoltenberg warned that if an investigation reveals a deliberate attack, there would be a "united and determined response from NATO."