Deep earthquake with 7.5 Magnitude Hits Off Eastern Russia, North of Japan: USGS
Last edited Tue Aug 14, 2012, 12:13 AM - Edit history (1)
Source: Reuters
Deep magnitude 7.5 quake off Russia, north of Japan
Mon Aug 13, 2012 11:19pm EDT
SYDNEY (Reuters) - A strong earthquake with a magnitude of 7.5 struck off the eastern Russian coast to the north of Japan, the U.S. Geological Survey said on Tuesday, but no tsunami warning was issued by Japanese authorities.
The quake was measured very deep at around 580 km (360 miles) below the earth's surface. Japanese television said the quake was measured at 7.3.
Read more: http://www.reuters.com/article/idUSBRE87D03820120814?irpc=932
= new reply since forum marked as read
A Wadati–Benioff zone (also Benioff–Wadati zone or Benioff zone or Benioff seismic zone) is a deep active seismic area in a subduction zone.[1] Differential motion along the zone produces deep-seated earthquakes, the foci of which may be as deep as about 700 kilometres (430 mi). The term was named for the two seismologists, Hugo Benioff of the California Institute of Technology, and Kiyoo Wadati of the Japan Meteorological Agency who independently discovered the zones.[2]
They develop beneath volcanic island arcs and continental margins above active subduction zones.[3] They can be produced by slip along the subduction thrust fault or slip on faults within the downgoing plate, as a result of bending and extension as the plate is pulled into the mantle.[4] The deep earthquakes along the zone allow seismologists to map the three-dimensional surface of a subducting slab of oceanic crust and mantle.
http://en.wikipedia.org/wiki/Wadati-Benioff_zone
so the movement over there (asia/indian plates) is also occurring at the mantle level as well...
Not to sound nuts but are these deep quakes any indication of magnetics or polarity shifts? aren't they related in some way...?
As far as polarity shifts no, they have pretty much zilch to do with plate tectonics. There is a great deal of residual heat from the formation of the Earth, as well as radioactive material giving off heat as it decays, all of which drives plate tectonics. Heat rises through the mantle, pushes against the crust driving it apart in places, and edges of the plates furthest away from these pushed areas are forced under into the magma-y deep. We know precious little about the core, which is a spinning ball of iron which creates the magnetic field. We do know that the field isn't created symmetrically and over time something has to give in the magnetic field, that's when you have flips. Your fillings won't get ripped out, planes won't fall from the sky, birds won't slither on the ground. Compasses will get screwy, the Earth will be a little less protected from incoming solar radiation, so there will likely be some increase in cancers and mutations but not enough to get freaked out about. The Earth's core will continue spinning for billions of years, and thus there will always be a magnetic field but with varying strength and polarity as it constantly tries to find an impossible balance with itself.
It's cool (well, hot I guess) stuff and you'll be fine. Worry less. 
