Seismologists discovered several underwater explosions in the Gulf of Finland on Thursday and Friday, but the causes of them are still unknown.

The explosions occurred close to Vyborg, a town in Russia.

Connections to the Nord Stream Leak, if any, are yet to be determined.

Researchers at the University of Helsinki's Institute of Seismology discovered the five explosions.

They discovered that the explosions occurred in the Gulf of Finland close to the Russian town of Vyborg, which is situated close to the Finnish border and about three hours' drive east of Helsinki, Finland.

Timo Tiira, the director of the institute, told Newsweek in an interview that On October 20, there were four explosions between 9:35 in the morning and 3:33 in the afternoon; on October 21, there was a fifth explosion at 00:08 UTC.

Earthquake Magnitude Explosions

When compared to the strength of an earthquake, the explosions had an intensity of between 1.3 and 1.8. Although it is too small to be felt by humans, a seismograph can measure its strength.

Tiira said that these unusual events are explosions rather than earthquakes based on signal characteristics.

He added that although the "events" had previously been found in the region, they did not occur annually.

Tiira further stated that the Nord Stream pipe runs further northeast, and the team is unaware of any infrastructure present in the area.

The team is scheduled to assess the depth of the explosions.

Read also: Understanding Nord Stream Methane Leaks: Environmental Impacts, Action Plans Identified 

Mysterious Explosions that Got the Nord Stream 1

The reported explosions coincide with the ongoing investigation into the unexplained explosions that in late September damaged a portion of the Nord Stream 1 gas pipeline.

Investigations revealed the pipeline had sustained significant damage, with about 50 meters missing from one section, according to South China Morning Post.

The cause of the explosions is still unknown despite police investigations.

The pipeline was built by Russia and other nations, and it is used to transport energy to other regions of Europe.

States in Europe and the US have attributed the pipeline explosions to sabotage, but it is unknown who may be responsible.

According to Russia, the US or possibly its allies were responsible for the explosions and that the pipeline ruptures took place in areas that were entirely under the control of the US intelligence agencies.

Meanwhile, support ships and submarines of the Russian navy not far from the locations of the Nord Stream leaks, Reuters noted.

America has disputed being involved in the event.

The explosions occurred as winter approached and European governments struggled with a current energy crisis, which is partially attributable to the interruption of Russian gas supplies as a result of political unrest between the West and Russia over the ongoing conflict in Ukraine.

By pipeline, Russia supplies 40% of the gas needed by the European Union, despite a 75% reduction in exports this year, Newsweek reported.

Related article: Scientific Trip Investigating the Nord Stream Leak Discovers Methane Levels Were 1,000 Times Higher Than Usual