Vanuatu Quakes continue

Shows how ocean ridges are formed, lithosphere...

Image via Wikipedia

Somehow I mistakenly said the quake yesterday was at Tonga, it was actually in Vanuatu, sorry for the mistake and confusion.

The 6 Magnitude quake I predicted happened as aftershocks continue but what I find interesting is that there was a sizable fore shock. This fore shock was a 5.1 north on the fault. This fore quake released energy and tension from the northern portion of the fault which allowed that pressure to transfer to the area where the magnitude 7 quake then ruptured.

We speak a lot of transfer of tension or pressure on quakes as one part of the quake lets go. The plates being pushed by expansion of mid-ocean ridges and by the plastic upper portion of the mantle flowing under the plates like water under ice. This puts pressure across the plate and causes it to press against the next plate, in these areas subduction zones. Now as part of the fault lets go the plate can’t spin to move itself forward at the part that ruptured although there is some elasticity letting parts move forward.

The pressure on the whole plate doesn’t decrease so it gets transferred to parts of the gets applied to the next sticking point. It can take time for the pressure to build to enough to rupture this next point, but in cases like this weeks Vanuatu fore-shock and subsequent quakes the rupture of the next big portion is quick and a link clearly established.


About echlinm

Computer Programmer/Systems Analyst/Hacker S31
This entry was posted in Earth Science, Earthquake, earthquakes and tagged , , , . Bookmark the permalink.

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