Complex sentence: Furthermore, plate subduction zones are associated with very large megathrust earthquakes, the effects of which are unpredictable and possibly adverse to the safety of long-term disposal, and disposal of nuclear wastes may cause havoc in the hadopelagic ecosystems.
Split into simpler sentences: Furthermore, plate subduction zones are associated with very large megathrust earthquakes, the effects of which are unpredictable and possibly adverse to the safety of long-term disposal. Also, disposal of nuclear wastes may cause havoc in the hadopelagic ecosystems.