Seismicity in Australia

• Introduction

• Table of Important Australian Earthquakes

• Seismicity in Queensland

• Seismicity in New South Wales

• Seismicity in Victoria, Tasmania and the A.C.T.

• Seismicity in South Australia 

• Seismicity in Central Australia

For a listing of recent Australian earthquakes, follow this link

INTRODUCTION

Earthquakes can occur in almost every part of Australia, although certain regions have a higher likelihood of experiencing an earthquake than others. Possibly the most earthquake prone regions of Australia are the West Australian wheatbelt, and the Flinders Ranges of South Australia. The alpine region of eastern Australia is also relatively active. Three Australian earthquakes are known to have caused fatalities. The 1902 earthquake near Warooka, on the Yorke Peninsula of South Australia (mag 6.0), caused two deaths, attributed to heart attacks. The 1935 Gayndah earthquake in Queensland caused one death. By far the most significant was the 1989 earthquake at Newcastle, NSW (mag 5.6), which caused 13 fatalities, mostly because of the catastrophic structural collapse of the Newcastle Worker's Club.

The body responsible for producing risk maps of Australia is the Australian Earthquake Engineering Society.

West Australian seismicity is treated separately on this site. Seismicity for the rest of Australia is summarised below.

BELOW - Map of earthquakes superimposed on Digital Terrain Model - courtesy Dan Clark, Geoscience Australia

-Below - earthquake risk map of Australia published by the Australian Earthquake Engineering Society

This map shows that the coastal regions of NW Australia are the most earthquake prone, and the region of east Australia to the west of the dividing range is the least.

TABLE OF IMPORTANT AUSTRALIAN EARTHQUAKES

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Although the Newcastle NSW earthquake of December 1989 was one of our most significant in terms of loss of life and damage, for sheer energy release, the activity which began in Tennant Creek, NT in January 1988, is probably more significant. Three magnitude 6 events occurred there within 24 hours, and complex surface rupturing occurred. Many thousands of aftershocks have occurred there since those events, and aftershocks are still occurring there.

Since the Tennant Creek earthquakes, the largest Australian event has been the Mag 6.3 event off Cockatoo Is., northern WA, in August 1997.

Between 2000 and 2002, a large swarm of earthquakes occurred near Burakin, WA. Burakin is approximately 200 km NE of Perth. Three earthquakes of magnitude 5.0 or more occurred in this earthquake swarm.

Since the 1997 Cockatoo Is. event, the largest Australian earthquake has been the magnitude 5.4 earthquake at Mt. Redvers, N.T., near the West Australian border. It occurred on Feb 11 2004.

The maps below were produced from extracts of the on-line data base of Geoscience Australia (www.ga.gov.au)

AUSTRALIAN EARTHQUAKES SINCE 1989, MAG 5.0 & ABOVE

Earthquakes in Queensland

Most of the seismicity in Queensland occurs along the eastern coastal region. One of the largest earthquakes to occur in eastern Australia occurred near Gladstone, north Queensland, in 1916. An important earthquake occurred near Gayndah in 1935. Although its magnitude was only 5.5, a worker was killed when he was shaken off a railway bridge near Biggenden.

Below - map of Queensland earthquakes, mag 3.0 & above, Jan 1990 to 12 May 2005

NB - for events of Mag > 4.5, date is shown alongside. Also, events north of 10 degrees South are not plotted.

Important Queensland earthquakes 1990 - May 2008

Earthquakes in south east Queensland, 1990 - May 2005

the largest event in the map above was a mag 4.7 event north of Bundaberg on 2nd Nov 1998

Important historical Queensland earthquakes

Neotectonic Features in Queensland

The Geohazards Group of Geoscience Australia (Canberra, ACT), is responsible for identifying and researching potentially recent fault scarps in Queensland, and Australia as a whole. Two such features include the Palmerville Fault, in far North Queensland, and a probable fault north of Roma, in soiuth-central Queensland. For more information contact Dan Clark of Geoscience Australia.

Below - Palmerville Fault, North Queensland

Below - Forestvale Fault, north of Roma, Queensland

Images courtesy of Dan Clark, Geoscience Australia.

EARTHQUAKES IN NEW SOUTH WALES

Newcastle, approximately 120 km north of Sydney, was the site of Australia's most devastating earthquake, on 27 December, 1989. Although its magnitude was only 5.7, 13 people were killed, and the damage caused has been estimated at 4 billion dollars.

The most significant NSW earthquakes are tabulated below.

IMPORTANT EARTHQUAKES OF NEW SOUTH WALES

Earthquakes in NSW, 1990 - August 2005, magnitude 3.0 & above

(for earthquakes in far south-east, refer to map of Victorian earthquakes)

Recent (2008) NSW earthquakes, mag >= 3.5

VICTORIA, TASMANIA, SOUTHERN NSW and the A.C.T.

In the period Jan 1990 to March 2005, 183 earthquakes of magnitude 3.0 or more were located by Geoscience Australia, in the area defined below. Twenty of these were of magnitude 4.0 or more. Many of the larger events were offshore, in the Tasman Sea.

Events of magnitude 4.5 or greater (4.0 or greater since 2002) are tabulated below

Mag 3.0 & above earthquakes, 1990 - Mar 2005, for Victoria, Tasmania, southern NSW and the A.C.T.

TABLE OF EVENTS, MAG 5.5 OR MORE, SINCE JANUARY, 1900

(within area of above map)

The above table starts in January 1990, because there were many large events in the Tasman Sea in the 1880's and 1890's. These constituted an earthquake swarm of some importance, and would cause a lot of concern if it were to happen in modern times. The larger events were felt widely in Tasmania and Victoria.

LARGE EARTHQUAKES OF THE TASMAN SEA PRIOR TO 1900

For more information on recent seismicity in this region, visit the web site of the Seismology Research Centre in Melbourne.

EARTHQUAKES IN SOUTH AUSTRALIA

South Australia has had a number of significant earthquakes. The largest was the Beachport earthquake of May, 1897 ( magnitude 6.5), off the south-east coast of the state. This caused massive damage in the towns of Kingston, Robe and Beachport, and exhibited some phenomena which are only seen in major events - eg liquefaction.

The Warooka earthquake, on the Yorke Peninsula of S.A. in September 1902, is important because it was the first of only three Australian earthquakes known to have caused fatalities. At least two people died during this earthquake. Its magnitude was 6.0, and its epicentre was approximately 100 km west of Adelaide. It was felt strongly in Adelaide - isoseismal maps indicate an intensity of 6 on the Modified Mercalli scale in the city.

The Adelaide earthquake of March, 1954 was of relatively low magnitude (5.5), but did the most damage, because of its proximity to South Australia's major city.

For more information on South Australian earthquakes, visit the website of the Dept of Primary Industries & Resources of South Australia.

Sth Aust earthquakes, mag 3.0 & above , Jan 1990 to August 2005

Yellow - Burra earthquake, 1997, Mag 5.0

Orange - earthquakes, magnitude 4.0 - 4.9

Below - more detailed view of Adelaide - Flinders Ranges region

South Australian earthquakes (magnitude > 4.2) since 1990

SA earthquakes 2008, mag 3.5 and above

LARGE HISTORICAL EARTHQUAKES IN SOUTH AUSTRALIA (MAG > 5.5)

Earthquakes in Central Australia

The 1991 map of earthquake risk in Australia, published by the Australian Earthquake Engineering Society, shows three main areas of high earthquake risk in Central Australia. Each of these areas relates to sustained levels of high earthquake activity at certain points in Central Australia.

These points are 1) Tennant Creek Area 2) Simpson Desert and 3) the Lake Tobin area of eastern Western Australia.

Below - 1991 map of earthquake risk in Australia - zoomed in to Central Australia ( star shows location of a small Tennant Creek earthquake, March 2004)

Recent large eartquakes  ( Mag >= 4.0) in the Northern Territory

Below - earthquakes in Central Australia to 2004 on Digital terrain model

(figure courtesy of Geoscience Australia)

Below - Gravity map for the above area (Geoscience Australia data)

DESRIPTION OF SEISMICITY IN INDIVIDUAL AREAS OF CENTRAL AUSTRALIA

Simpson Desert

The Simpson Desert, in the southeast of the Northern Territory, near the SA border,  saw a series of large earthquakes in the 1930's, beginning with a magnitude 6.5 event on 28 Oct 1937. Another series of large events commenced with another magnitude 6.5 event on 27 June 1941. After a long period of inactivity, a magnitude 6.2 event occurred in the area on 28 Aug, 1972.

The earthquakes of the 1930's and 1940's occurred before the development of the modern seismographic network, which began to take shape in the 1960's. Consequently, the accuracy of the locations given is not high. The error in locations is probably of the order of +/- 50 km. Although there is some scatter in the location of the events, the location accuracy does not discount the possibility that they are more closely grouped than the map suggests.

Lake Tobin, WA.

Activity in this region began on 24 March 1970, with a magnitude 6.4 earthquake. Numerous other quite large events occurred in approximately the same location overn the ensuing years. A magnitude 5.0 event on 13 June 1992, near the location of the magnitude 6 events, is probably an aftershock of these events.

While seismic station coverage was much better for these events than the Simpson Desert events, the lack of close stations again means that location accuracy is not as high as might be hoped, particulary for the smaller events in the region.

Reference Denham, D., Everingham, I., and Gregson, P.  Journal of the Geological Society of Australia, 1974.

Tennant Creek

Activity in this region began on 7 Jan 1987 with a magnitude 5.2 event, followed by another of the same size two days later. Prior to  these events, the region had been classified as aseismic. Activity died away after these two events, but resumed on a much greater scale a year later, on 7 Jan 1988, when three magnitude 6 events occurred there on the same day, and a major surface fault scarp, approximately 35 km long was created. The southern block was thrust over the northern block, and the maximum vertical displacement was approximately 1 m. The maximum horizontal displacement was approximately 2 m.

Magnitudes have been given as 6.3, 6.4 and 6.7, but the values may vary slightly, according to the agency which computed the magnitudes. Major damage was caused to the SA to Darwin gas pipeline. Unlike the earlier events, these events occurred close to a major array of seismic recorders ( the Warramunga array), and the subsequent locations have a relatively high degree of accuracy.

Seismic activity at this location has remained at above average levels since the magnitude 6 events. Small earthquakes are still occurring, the latest being a magnitude 2.9 event in January 2004. Larger earthquiakes from this location can still be expected.

Reference: Crone, A., Machete, M., & Bowman, J., US Geological Survey Bulletin 2032 (1992)

Marryat Creek

On 30 March 1986, a magnitude 5.9 earthquake occurred at Marryat Creek, at the eastern end of the Musgrave Ranges, and about 10 km south of the SA-NT border. A 13 km long, L shaped fault scarp was created by this event. The maximum displacement was approximately 0.6 m. vertically, and 0.8 m in an E-W direction.

A magnitude 5.6 aftershock occurred near the March event on 11 July 1986. The remoteness of these two events means that location accuracy is not high, and the two events could be closer than the earthquake coordinates suggest.

For more information, refer to the PIRSA website.

Other important earthquakes in Central Australia

Uluru. On 28 May, 1989, a magnitude 5.8 event occurred in a remote area, west of Mt. Olga. It has been titled the "Uluru" earthquake. It was felt over a wide area, including Alice Springs, but did no damage. Unlike many other large earthquakes of central Australia, no aftershocks were recorded, even though portable seismographs were positioned near the epicentre shortly after the earthquake.

Mt. Redver. On 11 Feb 2004, a magnitude 5.4 earthquake occurred in the SW on the Northern Territory, near the WA border. A magnitude 5.0 foreshock occurred 15 minutes before the main shock.

Earthquake locations in Central Australia 1980 - 2004

from the ANSS catalog

Date       Time             Lat       Lon  Depth   Mag Magt  Nst 
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1986/03/30 08:53:53.21 -26.1940  132.7670  10.00  5.80   Ms  193    
1986/07/11 07:17:59.07 -26.0790  132.7360  10.00  5.60   Mb  100 
1987/01/07 20:01:52.22 -19.9730  133.8980  10.00  5.20   Mb   56    
1987/01/09 11:27:12.68 -20.1100  133.6360   5.00  5.20   Mb   75     
1988/01/22 00:35:58.07 -19.8470  133.8030   5.00  6.30   Ms  270    
1988/01/22 03:57:25.26 -19.7980  133.9100   5.00  6.40   Ms  309     
1988/01/22 04:18:46.92 -19.9780  133.6630   5.00  5.10   Mb   17   
1988/01/22 12:04:57.88 -19.8290  133.8820   5.00  6.70   Ms  344   
1988/01/27 11:27:17.12 -20.0670  133.6050   5.00  5.10   Mb   47     
1988/01/29 10:19:30.84 -20.0030  133.7450   5.00  5.60   Mb   98     
1988/02/06 05:23:57.95 -16.6790  124.6630  10.00  5.20   Mb   57   
1988/02/06 19:08:26.41 -19.5670  133.7990  10.00  5.00   Mb    7     
1988/09/30 20:42:58.13 -20.0480  133.8650   5.00  5.30   Mb   64      
1989/03/30 12:46:25.67 -19.9040  133.6450   5.00  5.30   Mb    7       
1989/05/28 02:55:19.65 -25.0530  130.7810  10.00  5.80   Mb  132 
1991/03/07 01:28:10.54 -20.0820  134.0250   5.00  5.20   Mb   44     
1991/06/19 11:38:23.39 -20.1340  133.9520  10.00  5.20   Mb   49     
1991/07/08 10:45:33.78 -20.2250  133.8250   5.00  5.10   Mb   39      
1992/06/13 18:05:17.88 -23.5800  130.2840  10.00  5.00   Mb   28     
1992/07/15 00:17:05.14 -22.3630  126.5290  10.00  5.20   Mb   38    
1997/08/10 09:20:30.98 -16.0130  124.3290  10.00  6.30   Mw  269      
2004/02/11 09:17:58.00 -22.7380  129.8710  13.00  5.00   ML   32   
2004/02/11 09:30:39.00 -22.6800  129.8230  13.00  5.40   ML   37