Two undersea leaks that began in the Russian-owned Nord Stream gas pipelines on Monday were likely caused by powerful underwater explosions, according to Swedish and Danish seismographic data. It is ‘very clear from the seismic record that these are blasts,’ Björn Lund, director of the Swedish National Seismic Network at Uppsala University told NPR in a phone interview. ‘These are not earthquakes; they are not landslides underwater.’ German and Danish officials said both the Nord Stream 1 and Nord Stream 2 pipelines showed sudden losses of pressure late Monday, which they said could only be caused by a leak from large holes in the pipelines.