An undersea volcano erupted in spectacular fashion near the Pacific nation of Tonga on Saturday, sending large waves crashing across the shore. A tsunami advisory is in effect for Hawaii and the U.S. Pacific coast | Bloomberg Originals

A Massive Underwater Volcano in the Pacific Is Showing Signs of Eruption A huge submarine volcano beneath the Pacific Ocean is displaying increased seismic activity, gas release, and ground swelling—signals that scientists monitor closely for potential eruption. Most underwater eruptions pose little immediate threat to humans, but large events can affect ocean ecosystems, shipping routes, and even trigger tsunamis under rare conditions. Important Details: • Located deep beneath the Pacific Ocean