posted on Jul, 2 2011 @ 08:31 PM
It would have been nice to have this thread as part of the VOLCANO THREAD; keeping all related issues easy to find on later stage for references.
Contrary to what many people believe, NABRO is actually a VERY large volcano that spans about 70 km E-W and 75 Km N-S. It consist of three large
vents, different local names but on Google Earth these are Asavyo (Oldest), Aruku, and Nabro and most likely also includes Dubbi as the youngest vent.
Additionally there are 7 smaller vents and about 104 small vents in this volcano field.
@Foxe; Nabro is still ongoing to this day. It has not stopped eruption since first explosion. Now there is less ash cloud; but still lots of steam
and magma. I already had a series of agreements on VOLCANO WATCH that the Arabian plate is diving under the Nubian plate - thus it is in fact forming
a subduction zone.
@Kro32; you are only 50% correct. Nabro is in fact closer to Felsic (Rhyolitic) magma than Mafic Basalt. If you observe the 'pulses; during this
current eruption the periodic closures and explosions are evident.
I posted this elsewhere, so copy here for sake of info:
"What happens when the pressure is released is that this rhyolitic lava forms a layer of glass like hard rock which acts like a shield barrier.
Now pressure is building up below and can't escape to the surface. Until one day when the pressure is enough to crack the 'glass'. A short series of
earthquakes are the indication of such 'cracking glass'. Eruption temperature is somewhat lower at about 900 C; likely also due to the pressure drop.
Consider in this Nabro region the crust is around 23 to 25 km thick it does not take very long to reach the surface. At last the final top is blown
off and the volcano can 'deflate' somewhat. When pressure is low again, the glass top (in this case Felsic) seals again and the whole cycle starts
building again. "
FUTURE OF NABRO
Magma chambers takes time to fill and once filled, then it starts building up pressure, this vary from volcano to volcano. That is where we get a
sort of time frame to determine periodic eruptions. In the case of Nabro everything is completely unknown. This current eruption releases the
pressure in the magma chambers thus it is quite unlikely to have another massive explosive eruption soon. On the other hand this whole region is so
active (and young) NO PREDICITONS ARE POSSIBLE AT ALL.
On top of it all; this region is very little studied. Not major population, no major importance . . . until maybe somebody realises Nabro and his
siblings could close the Red Sea passing for ships!
The pressure potential under any of the volcanoes in Eritrea, NE Ethiopia, Djibouti (Afar Region) and Western Yemen are not possible to build up to
the same explosive powers you have from Krakatau. However there are other factors that could and would probably be more disruptive. These volcanoes
produce more Sulphur Dioxide, CO2 and the dust particles are smaller glass like which are serious issues for health, global temperature and air
edit on 2/7/2011 by Aromaz because: (no reason given)