Describe how seismic waves and earthquakes can be measured.

Seismic waves can be measured by seisometers. For example the 'San Andreas Fault Observatory at Depth' where seisomoters have been placed in an L-shaped bore hole accross the faultline at Parkfield.

Earthquakes can be measured by their magitude/intensity on the Richter Scale. The Richer Scale measues the energy released by the earthquake and is a logarithmic scale (an increase in magnitude of 1 = tenfold increase in energy released) .

Earthqukes can aso be measured by the Mercalli Scale which records the level of damage caused by an earthquake based on observations. For example, level 1 on th Mercalli Scale accounts fo earthuakes which are detected by seisometers but barely felt, whereas level 12 records earthqukes which cause extensive damage.