Bardarbunga volcano update: Predicting the end of the eruption in March 2015
Monday Jan 19, 2015 14:29 PM | BY: T
Observed caldera subsidence versus time - if the modeled curve is correct, it should flatten out in March this year and might mean the end of the eruption (source: visir.is)
This audacious prediction is based on extrapolating the observed ongoing slow subsidence ("collapse") of the central volcano's caldera floor, located under 800 m of ice, and assuming that it is a direct indicator of the magma erupted at the Holuhraun fissure.
The underlying model is based on a number of assumptions:
- magma from the reservoir underneath the caldera is drained through a 50 km long underground "tunnel" (more likely a fissure-like feature) to the eruption site
- the evacuated volume corresponds more or less to the one erupted.
- the subsidence of the caldera is a result of pressure adjustment in the magma chamber. Once the pressure in the magma chamber reaches a balance (equals out with lithostatic pressure, i.e. the weight of the overlying rocks and ice), the caldera subsidence and supply of magma to the eruption site would stop.
- the observed rate of subsidence is amazingly regular and therefore it is reasonable that it can be extrapolated using a best-fit mathematical curve.
Using this approach, the rate of caldera subsidence is modeled as a simple square-function curve that flattens out in March. That would imply a pressure equilibrium in the magma chamber and the end of magma supply, hence the end of the eruption.
The volcano and time will tell whether this prediction holds!
Source: Volcanoist has calculated when the eruption will end (Visir.Is)
http://www.volcanodiscovery.com/bardarbunga/news/50413/Bardarbunga-volcano-update-Predicting-the-end-of-the-eruption-in-March-2015.html
--
__._,_.___
No comments:
Post a Comment