Volcano Watch: Using the ocean to track volcanic activity at Kilauea

  • A Hawaiian Volcano Observatory scientist services one of the temporary seismometers deployed on the down-dropped block at Kilauea summit near the rim of Halemaʻumaʻu crater. Instrumentation associated with HVO’s permanent Global Positioning System (GPS) network can be seen in the background. (USGS photo by N. Bennington)

Ocean swells occur continuously around the world. As these swells rise and fall, they couple with the ocean floor below them creating a constant signal. These signals, called oceanic microseisms, travel through the solid earth and are observed at the surface using instruments called seismometers.