These are used to detect plate movement.
Picks up vibrations in the Earth's crust. An increase in vibrations may lead to a possible earthquake.
Escapes from cracks in the Earth's crust. A sudden increase may suggest an earthquake.
Some people believe that they sense earthquakes before they happen. Changes in behaviour may indicate an earthquake.
Monitoring water levels:
Changes in levels may indicate a shift in the rocks below a lake or river.
Monitoring electrical charges:
There is evidence that foreshocks, (small tremors) and electrical discharges increase before an earthquake.
Using GPS technology:
This checks whether the volcano is bulging as a result of rising magma.
Gas sampling (composition):
Changes in gas composition indicate the activity levels of the gas underground.
Geothermal monitoring from space:
This records changes in heat as magma approaches the surface.
This allows scientists to "listen" to the rising blobs of magma as they force their way upwards and cause small earthquakes.
Records of past volcanic eruptions allow scientists to see if there is a regular pattern to the eruption.
Preventing the effects of earthquakes
- Educating local resisdants on how to prepare and react. Having an emergency kit ready with a torch, bottled water, first aid kit and tinned food.
- Rubberised foundations on buildings allow the building to absorb the shock
- Planning regulations determine how high buildings can be
- Counter weights (weights which sway in the opposite direction to the building) return buildings to an upright position
- Shutters cover windows which might shatter
- Designing buildings to withstand minor earthquakes by having flexible steel frames, which sway as the ground moves
Preventing the effects of volcanic eruptions
- Spraying the lava to cool it down, making it solidify and stop flowing
- Putting concrete or rock barriers in the path of the lava to divert it away from villages
- Setting off explosions to divert the lava
- Digging ditches to divert the flows away from areas of risk