Abstract

In the paper double seismic zones are discussed as a phenomenon confirming penetration of oceanic lithosphere through the mantle as solid and extremely hard medium. Formation of such medium has been performed by solidification of Earth from core-mantle boundary upwards. Lower mantle formed under extremely high pressure prevents any earthquakes. Upper mantle is suitable for formation of embrittlement and earthquakes in double seismic zones. Continental lithosphere overriding oceanic lithosphere forms subducton zones firmly anchored in mantle. Deeply steeping subduction zones penetrate mantle burning its way by melting probably as far as through core-mantle boundary. Oceanic lithosphere grows in midocean ridges with half speed of the front of plate. Driving forces are tides. Movements of plates confirm hotspot tracks. Hotspots are probably of meteoric origin. They penetrate through mantle in same way as subducton zones. Material created in penetration moves upwards by buoyancy and during its subsidence creates hotspot tracks over 10 000 km, however their penetration as far as coremantle boundary is not proven.