saw a show today explaining where all the heavy metal came from originally
and the theory postulated is that our Earth's interior core
is similar to a nuclear reactor...
these cores (@ nuke plants) we keep cool and stable with constant monitoring
of temperatures and water
...but the earth is a self regulating
reactor.... and it may have to blow chunks
once in awhile
every 230 years or so to do just that...
there is a reason all the real old brick buildings down south
are bolted together and thats because of a HUGE quake
that 2/3 rds of All American's felt back in the 1800's