Analysis of Nord Stream explosions using seismic recordings

As a significant detection task, underwater explosion events have piqued the interest of geophysicists. On September 26, 2022, two underwater explosions occurred in the Baltic Sea region involving the Nord Stream pipeline. Subsequent reports from the media and the European-Mediterranean Seismological Centre deduced that one event was detected at 17:03:49 GMT, exhibiting a magnitude of 3.1 on the Richter scale, whereas the second event lacked comprehensive information. To meticulously investigate the details of the two Nord Stream incidents, we employed 14 proximate stations for subsequent analysis. Using a linear inversion technique, we determined that the two events occurred at 00:03:30 and 17:03:49, with corresponding coordinates of 54.87°N, 15.52°E and 55.59°N, 15.80°E, respectively, and Richter magnitudes of 2.3 and 3.1, respectively. Spectral analysis corroborates that both events were underwater explosions, and the presence of anomalous signals within the frequency domain may provide valuable insights into source parameters and characteristics, particularly for the first event.