- Hot spots
- Radioactive decay within earth = high temperatures
- If concentrated then hot spots around the core form = heat lower mantle = localised currents= plumes magma rise.
- Plumes burn through the lithosphere = volcanic activity. As hot spots stationary movement of plates = formation chain active and extinct volcanoes.
- Hawaii - December 09 - less dense magma plumes pushes through litosphere picked up my seismometres.
- Currently hot spot underneath southern end of hawaii, Pacific plate moves NW 5-10cm pa. next one in 200,000 years. To NW extinct sink to ocean.
- Any bends are result in change of movement of pacific plate. New shield volcanoes are above hotspot = runny lava.
- As moves away from HS lava becomes more alkaline =spatter cones. Final phase more violent eruptions and pyroclastic flows.