My science/technology-related thoughts, sometimes controversial, sometimes can be based on limited knowledge base, logic can be non-perfect as well. I develop my vision in iterations. Don't take this blog as an attempt to convince anybody in anything.
Each post in this blog reflects my level of understanding of Tectonics of the Earth at the time the post was written; so, some posts may not necessarily be correct now.

27 May, 2011

Broken Subduction To Cause Earthquake And Tsunami.

   Imagine an oceanic (Pacific) plate is being subducted under a continental (Asia) plate from east to west. The  oceanic plate is not totally uniform. The most notable anomalies in my opinion are divergent boundaries, active or deactivated.

   The anomalies along the most stressed part of the subduction zone may lead to the rupture along the fragment of the subducted divergent boundary. The divergent boundary is a very thin, not yet fully solidified, highly irregular, and, therefore, weak juncture between plates.

Important is that the stress within the fragment is compression / bending. The compression is caused by distant divergent boundary pushing the oceanic plate under the continental plate. The bending stress is due to the oceanic plate moving down. The oceanic plate serves as a gigantic spring to store the energy a distant divergent boundary develops under Moon/Sun induced deformations, the energy to be released in the form of the rupture. How would a compressed / bent plate broke in normal life? There will be a rupture and the ridge of the rupture would go off perpendicular to the surface.

   In our case the ridge of the rupture would go up and west. Taking into account that the fragment on the west of the rupture is more molten than the fragment on the east,  the motion will be even more to the west. This would produce tsunami to west and anti-tsunami to east.

   The dynamics of the rupture should have a prehistory which, in my opinion, can be recognized prior to the rupture. Some of the detectable properties could be:
- usual set of divergent boundary features: numerous "molten" anomalies (higher seismic wave speed) within the future rupture line, thin crust, very thin viscous layer, magma is quite high here.
- sequences of the moderate deep earthquakes by which magma propagates through the crust (See "Intraplate Magma Transport. The Concept Of Moving Transition Zone." )
- pre-displacement under the force by the distant divergent boundary, as the zone gets hotter on average and therefore "less solid".
- oceanic water properties change due to magma having reached surface of the crust (probably could affect atmosphere as well).

   The described mechanism is heavily based on the assumption that the oceanic floor spreading mechanism is fueled by magma solidifying in the crust ruptures caused by Moon/Sun induced crust deformations (see "Divergent Boundaries Spreading Mechanism By Magma Solidifying In The Crust Ruptures Caused By Moon/Sun Induced Crust Deformations." ).
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