'Supervolcano' forming near New Zealand
Supervolcanoes occur when vast quantities of magma build up beneath the surface over a large period of time, eventually erupting in a single destructive event that tends to have dire consequences for life on Earth.
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“Geologist [I'm Climate Change]”
Since: Mar 07
#1 Feb 18, 2013
This mantle plume is also known as the "Fiji plateau"
The easiest way to see it is to key into the NEIC website (Earthquakes), and look for a quake in the Tonga arc in the deep crust in the "curl" at the top of the arc.
Once there look at "Historic seismicity, since 1990".
The view will show a contour map of the descending cold pacific plate under Tonga heading to greater depths under Fiji. The important bit is that @ Fiji the descending plate is being bowed back up into a dome under the SW, part of Fiji by the rick rising above the mantle plume.
Of further interest here is the fact that the "Fiji plateau" is actually uplifted deep ocean crust which is as a result spreading in all directions. The result is lots of active radiating rifts in the upper crust which are visible N. and W. of Fiji extending to Vanuatu.
Last but not least (especially for NZ) is the Hunter ridge backarc basin, the source of the magma erupting in the Fiji volcanoes. This actively spreading backarc basin is in the latest stage of recompression with the Fiji colcanoes in the least compressed E. section @ Fiji now dorrmant. The activity of the Fiji volcanoes indicates that the current dormant period is unusual and the last event may have decompressed the entire fiji plateau.
Continued spreading will eventually break the Hunter ridge megathrust resulting in a bloody great big tsunami @ NZ from the N. as the crust of the Hunter ridge & Fiji relaxes south. The runout would be anywhere from 30 to 500 metres and may last anywhere from 10 minutes to an hour two. The Tsunami produced would for short runouts approximately equal the runout, and would top out at about 85m for long runout events... and will be followed by a very long wave train for the longest runouts. The west part of the Hunter ridge around Hunter island may have already relaxed, alternatively the telescoping Vanuatu arcs may be absorbing the recompression with the result being that a magathrust quake would cover the entire sweep of the hunter ridge.
Keep watching that space.
Have a nice day: Ag
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