GCSE Natural Hazards

Holderness loses metres of till each year; the Himalaya gain millimetres of rock. Both are plates doing different jobs at their edges.

Focus is in the rock. Epicentre is the map dot. P, then S, then the surface wave that does the damage in town.

Viscosity is the plot. Shield, strato, rift — three shapes from one slider.

Seafloor slip lifts a water column. In deep water the wave is fast and low. At the coast it stands up.

Eye, eyewall, rainbands. Warm sea is the fuel. A UK depression is usually a different machine.

The 1953 North Sea flood was wind piling water onto a shelf. Katrina’s surge was the same machine on the Gulf. It is not a tsunami.