Storm Ciarán pounded England's Newhaven Lighthouse and harbor wall on Nov. 4, 2023. AP Photo/Kin CheungAs oceans waves rise and fall, they apply forces to the sea floor below and generate seismic waves. These seismic waves are so powerful and widespread that they show up as a steady thrum on seismographs, the same instruments used to monitor and study earthquakes. That wave signal has been getting more intense in recent decades, reflecting increasingly stormy seas and higher ocean swell. In a ne