Scientists Stunned by Mysterious Underwater Explosion in Pacific Ocean A bizarre underwater explosion has left experts scratching their heads, as a massive sonic boom was detected in the Pacific Ocean. According to reports, the blast, which occurred on April 30th, was so powerful that it was picked up by seismic monitoring stations over 1,000 miles away. The cause of the explosion remains unknown, sparking a flurry of speculation and theories among marine biologists and geologists. As investigators scramble to determine the source of the blast, concerns are growing about the potential impact on marine life and the ocean's ecosystem.