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Buckled railway lines caused by the 1968 Meckering Earthquake
Reproduced with permission from Alice Snooke
Tectonic plates
© Geoscience Australia
Plate margins near Australia
Reproduced with permission from USGS
Newcastle earthquake, December 1989
Reproduced with permission from EMA
Disaster recovery
Reproduced with permission from EMA
Aftershock sequence,
Northern Territory
© Geoscience Australia
Quaternary fault scarp,
Southwest Tasmania
© Geoscience Australia
Meckering earthquake,
Western Australia 1968
© Geoscience Australia
Earthquake Epicentres and Recent Fault Scarps
© Geoscience Australia
A Seismograph
© Geoscience Australia
$About 5% of the energy released in an earthquake is radiated as seismic waves. A seismogram is the recording of these seismic waves as detected by a seismograph. As the waves travel through the body of the Earth (Primary and Secondary waves) or around its surface (R and L waves) they encounter faults and layers of different density rock. At these boundaries seismic waves are reflected, refracted and converted to other phases (Primary to Secondary and Secondary to Primary) so a seismogram may be very complicated. For example, the seismic primary wave arrives at the seismograph station as a primary wave which has been converted from a secondary wave when reflected from the Earth's core/mantle boundary or moho (Mohorovicic discontinuity). Accurate interpretation of the seismogram reveals information about the earthquake and about the nature and composition of planet Earth.$
A seismogram recording
© Geoscience Australia

Topic contact: earthquakes@ga.gov.au Last updated: July 18, 2011