Slashdot Mirror
Seafloor Sensors Record Possible Eruption of Underwater Volcano
vinces99 writes: Thanks to high-tech instruments installed last summer by the University of Washington to bring the deep sea online, what appears to be an eruption of Axial Volcano on April 23 was observed in real time by scientists on shore. "It was an astonishing experience to see the changes taking place 300 miles away with no one anywhere nearby, and the data flowed back to land at the speed of light through the fiber-optic cable ... in milliseconds," said John Delaney, a UW professor of oceanography who led the installation of the instruments as part of a larger effort sponsored by the National Science Foundation. Delaney organized a workshop on campus in mid-April at which marine scientists discussed how this high-tech observatory would support their science. Then, just before midnight on April 23 until about noon the next day, the seismic activity went off the charts. The gradually increasing rumblings of the mountain were documented over recent weeks by William Wilcock, a UW marine geophysicist who studies such systems. During last week's event, the earthquakes increased from hundreds per day to thousands, and the center of the volcanic crater dropped by about 6 feet in 12 hours. "The only way that could have happened was to have the magma move from beneath the caldera to some other location," Delaney said.
Before engaging in such speculation maybe you should calculate the volume of water you are talking about and the amount of energy it would require to raise that volume of water the temperature difference and compare that amount of energy to the known heat output of volcano's assuming every bit of energy is converted to heat.
Once you've done that calculation then you can come back and speculate knowing that there is no way in hell a volcano could actively heat that volume of water and hold that temperature fairly constant for several years unless it was the largest super volcano the planet has ever seen. It takes a LOT of heat to raise the temperature of even small volumes of water and the volume of water you are talking about is NOT small.
No volcano's aren't raising the temperature of the ocean in anything but the smallest of areas directly adjacent to the eruption, nor are they the source of climate change. If what you suggest was possible all the water around the island of Hawaii would be near boiling because of all the lava entering the ocean there.
Another way to look at this: total energy from the sun that hits the earth is 170 petajoule/second. Size of the blob is 1000x1000 miles, or 0.5% of the earth's surface. That means that the blob gets an average of 0.85 petajoule/second from direct sunlight. Energy from the Krakatoa eruption (largest volcanic eruption in recorded history) is estimated at 800 petajoule.
In other words, just the sun hitting the area of the blob provides the same energy as a Krakatoa-sized eruption every 15 minutes. I think we would have noticed if such huge eruptions were going on.
And this doesn't even take into account your point that the warming from the sun is from above, and the volcanic warming would be through several miles of cold ocean water.