Submarine Volcanic Eruptions
Submarine Volcanic Eruptions Sounds
NW Rota Eruption Recording
Scientists recorded hydrophone sound data from NW Rota during an eruption in 2006. The hydrophone was placed on the summit of the volcano a safe distance from the eruptive pit. Sound courtesy of Submarine Ring of Fire 2006 Exploration, NOAA Vents Program.
Scientists use underwater acoustics to map, monitor, and evaluate the eruptions of submarine volcanoes. Acoustic data make it possible to quantify the character of submarine volcano activity, including duration, frequency, intensity, and evolution over time of eruptions.
The Mariana Volcanic Arc, located in the western Pacific Ocean, north of Guam, contains at least 20 submarine volcanoes. In 2004, at submarine volcano NW Rota-1, with a peak 517 m below the surface, scientists observed and recorded the sounds from an underwater eruption. Ash and lava fragments were spewing from the volcano. Hydrophones recorded acoustic data during cyclical gas-driven bursts lasting 2-6 minutes. These bursts were separated by shorter, non-eruptive intervals lasting 10-100 seconds. The short “pauses” were associated with cooling lava that forms a temporary quench cap over the vent site. Gas pressure builds beneath this cap, until the cap is eventually blown apart.
Acoustic signals of the gas-driven explosions have frequencies of 1-80 Hz, with a peak at approximately 30 Hz. Each acoustic burst starts suddenly. The amplitude gradually rises for 30 seconds, and then sharply increases further. This higher amplitude is often sustained for the duration of the acoustic burst. In 2008, underwater explosions with a broadband sound source level of 192 underwater dB were recorded.
Other submarine volcanoes in the Marianas Arc, as well as other arc volcanoes in the Lau Basin and other Pacific locations, have been studied using underwater acoustics.
Additional Links on DOSITS
- NOAA/PMEL: Earth Oceans Interactions (EOI) Program, Mariana Arc
- NOAA: NE Lau Basin- EOI Program
- NOAA Ocean Explorer: Submarine Volcanism 2004
- NOAA Ocean Explorer: Submarine Arc Volcanism
- Smithsonian Institution Global Volcanism Program, entry for Rota-1