Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
Part 1: A description of the natural hazard
What is an Earthquake?
An earthquake is the vibration and shaking of the ground, as a result of the
movement and abrupt splitting of the Earth’s tectonic plates belonging to the Earth’s
rock, in the outermost crust. Most earthquakes occur along the fractures which mark
the edges of these tectonic plates, and the tectonic plates either collide or rub
against each other. The size/magnitude of an earthquake is calculated through the
measuring of the amplitude of the seismic waves, which are recorded on a
seismograph, as well as the distance of the seismograph from the earthquake. These
results are converted to a magnitude, through the use of a formula. The word
‘magnitude’ is a unit of measurement of the energy released from the earthquake.
The shifting masses may result in forces cable of:
 Altering surface of Earth – thrusting up cliffs, opening great cracks in ground
 Collapsing man-made structures (physical environment e.g. buildings, homes,
etc.)
 Destroying power/gas lines (leads to fire)
 Leading to other natural disasters – landslides, snow avalanches, tsunamis,
volcanic eruptions
PARTS OF AN EARTHQUAKE
Fault/Fault Plane:
Surface where two blocks of earth suddenly slip past
each other
Hypocenter:
Area below earth’s surface where earthquake starts
Fault/Fault Plane:
Location on surface of earth, directly above
hypocentre
Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
The Kalgoorlie-Boulder Earthquake – WA, 20 April 2010
Background:
The Kalgoorlie-Boulder Earthquake was a 5.0
magnitude earthquake that occurred in Western
Australia, 20 April, 2010, near the city of
Kalgoorlie-Boulder. The earthquake took place
around 8:17am (WST), with an epicentre of
approximately 10km (10mi) southwest of
Kalgoorlie, at a depth of 10km (6.2mi). The
Location of Kalgoorlie-Boulder Earthquake, WA
earthquake, which lasted 10-15 seconds, caused
tremors up to 1,007km (626mi) away. One of the
largest ever in the Goldfields region, it led to major damage of historic buildings and the
closure of local goldmines, including the Super Pit gold mine. However, this earthquake did
not result in the deaths of anyone, though two individuals required minor treatment at
Kalgoorlie Hospital.
Causes:
What is a mainshock?
According to the USGS, “The mainshock is
the largest earthquake in a sequence,
sometimes preceded by one or more
foreshocks, and almost always followed
by many aftershocks.”
The Kalgoorlie-Boulder earthquake, which led to major damage to historical buildings and
injured two people, was the strongest earthquake in the goldfields region in 50 years. The
quake occurred under the southern part of Boulder, at a depth around 1.7km. The
epicentres of the aftershocks extend 3km in the north-southerly direction, thus providing an
estimate of the overall rupture length of the mainshock. At the east of the mainshock, a
large fault takes place, dipping in the direction of Boulder. This fault intersects the location
of the mainshock, at a depth of 2-3km, hence making it a prime candidate for being the fault
that ruptured during the earthquake.
Super Pit Mining Site
Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
Map of Australia and its major cities:
Map Key:
 Major City
 Location of
earthquake
Kalgoorlie on the map of Australia:
Location of Kalgoorlie-Boulder
Earthquake:
30.7489° S, 121.4658° E
Distances of Kalgoorlie-Boulder from major cities in Australia:
Major City
Perth
Darwin
Cairns
Townsville
Brisbane
Gold Coast
Newcastle
Sydney
Geelong
Hobart
Melbourne
Adelaide
Distance of earthquake from major city (km)
600
2258
2899
4374
3810
3867
3401
3400
2861
3610
2882
2159
Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
Landform and climate of Kalgoorlie-Boulder:
Climate
Since Kalgoorlie-Boulder is located on the edge of a desert, it often results in high temperatures
during the months of summer, averaging between 18-34oC. Winter days in Kalgoorlie-Boulder are
relatively sunny and bright, though temperatures can drop fairly in the evenings and temperatures
average around 5-7oC.
Kalgoorlie-Boulder Climograph
Landform
Unlike New Zealand and Indonesia, which sit along tectonic plate boundaries, and constantly
experience earthquakes, Australia has low seismicity. Therefore, it has low seismic risk leading
Australia to low resistance towards natural hazards such as earthquakes. Hence, it is vulnerable, due
to its combination of hazard and community exposure, as well as infrastructure vulnerability.
Kalgoorlie-Boulder is, in terms of area size, the largest city in the whole of Australia, and possesses a
number of historical buildings. These older and unreinforced masonry buildings contributed
disproportionately to community risk, especially when affected and destroyed by earthquakes, such
as the Kalgoorlie-Boulder earthquake in 2010.
View of Kalgoorlie showing the
epicentre of earthquake and location
of buildings surveyed between 18
and 22 May 2010
Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
Changes due to Kalgoorlie-Boulder earthquake:
Social and environmental:










Two individuals injured
Approx. 40 public and commercial buildings have had wall and roof damage
Most damaged occurred in Boulder area – predominantly on streets of Burt, Moran and
Piesse
29 buildings cracked – 2 with significantly damaged walls and collapsed chimney
Balcony collapsed at Golden Eagle Hotel (Lionel Street, Boulder)
Structural damage occurred at Rock Inn (Burt Street)
Ceiling collapsed at Boulder Primary school, minor damages at O’Connor Primary School,
North Kalgoorlie Primary School, Kalgoorlie Primary School and Kalgoorlie School of Air –
students remained unharmed, schools open
Firefighters attended to gas leak on Hopkins Street
Local mines evacuated
Kalgoorlie prison had minor damage, but no harm to inmates
Economic:



The mining industry suffered - as all mines in area had to be closed
Closure included Super Pit (Australia’s biggest open-cut mine) – had to be evacuated and
shut, pending geological assessment
No workers injured
Responses to Kalgoorlie-Boulder Earthquake:
In response to the earthquake, individuals began claiming from insurance companies. According to
the RAC, they had already received more than 20 claims early on and had started working to assess
the extent and cost of the damage. Apart from this, 30 emergency vouchers had been issued
overnight, mostly to mining workers who were staying at historic hotels, damaged by the
earthquake. Also, five structural engineers were flown in to assess the damage. Now, 3 years on, the
rebuilding of Kalgoorlie-Boulder is complete. Both the Western Australian Government and local
members of the city have collaborated, contributing to the multi-million effort in repairing damages.
These include areas such as Town Hall, which according to Mayor Ron Yuryevich last year, was
almost complete, along with significant hotels that required scaffolding. Overall, the rebuilding is
complete, with 80% done and over 400 building licences issued in 2012.
Year 9 Geography Research Report: The Kalgoorlie-Boulder Earthquake
Gayle Ting
Conclusion:
In conclusion, it is clear in this report that the Kalgoorlie-Boulder earthquake was the biggest
earthquake in the Goldfield region, which led to the devastation of numerous historical buildings in
Kalgoorlie-Boulder, and injured two individuals. Though thankfully, it did not result in any deaths. It
is evident in this report that the earthquake had a variety of impacts on a number of aspects. In
response to the earthquake, locals and governments cooperated with each other, in a joint effort to
rebuild this broken city, eventually doing so successfully.