Seismicity of Western Australia - Large earthquakes of Western Australia

Many relatively large earthquakes are known to have occurred in Western Australia since the arrival of European settlers in 1824. Details of the earlier events have been estimated from newspaper accounts.

The most significant West Australian earthquake was that which occurred at Meckering in October, 1968. It basically destroyed the small wheat belt town, approximately 100 km east of Perth, and caused several injuries, but fortunately no deaths. It's magnitude was 6.9, and caused surface faulting up to 3 metres high, and nearly 40 km long. However, it was not WA's largest earthquake. That distinction belongs to an event near Meeberrie, approximately 300 km northeast of Geraldton. It occurred in April 1941, and had a magnitude of 7.3. Because it was in a remote location, it caused little damage, and no known surface faulting has been attributed to it.

Another important earthquake in WA's history is the Cadoux earthquake of 1979. At magnitude 6.1, it was not as large as the Meckering event, but still caused major damage to the small wheatbelt town of Cadoux, and also caused surface rupturing, about 15 km long.

A third West Australian earthquake is known to have caused surface faulting - the Calingiri earthquake of June 1971. Calingiri is also in the WA wheatbelt region, and the significant earthquake activity which has occurred over time in this region lead to the identification of a zone of seismicity known as the Southwest Seismic Zone.

Another important earthquake is one which occurred in 1906 off the WA coast, about 400 km NW of Exmouth. Because it occurred before world earthquake monitoring had really developed, little is known about it. However, with an estimated magnitude of 7.5, it is probably the largest earthquake known to have occurred in the Australian region.

#PRE-1900#PRE-1900 EARTHQUAKES

Everingham & Tilbury published a report ( Journal of the Royal Society of Western Australia, 1972) on research of early newspapers and journals in WA. They discovered many earthquake reports, two of which they concluded were caused by earthquakes of magnitude 6 or more. The first was a report in the diary of explorer Earnest Giles, who, on 15 Dec 1873 was in the Barrow Ranges, in far eastern WA, near the SA/NT border.

"I felt ill again from my morning's walk, and lay down in the 110 degrees of shade, afforded by the bough gunyah which Gibson had formerly made. I had scarely settled myself on my rug when a most pronounced shock of earthquake occurred, the volcanic wave, which caused a sound like thunder, passing along from west to east right under us, shook the ground and gunyah so violently as to make me jump as though nothing was the matter with me. As the wave passed on, we heard up in the glen to the east of us, great concussions, and the sounds of smashing and falling rocks hurled from their native eminences, rumbling and crashing into the glen below".

Everingham & Tilbury estimated a magnitude 6 for this earthquake, based on the above report.

Geraldton area, 5 January, 1875

A severe earthquake was experienced in the Geraldton area, in the evening of 5 January, 1885, and was reported in many local papers. Based on these reports, Everingham and Tilbury (1972) estimated that the earthquake had an epicentre about 100 km from Geraldton, and a magnitude of approximately 6.5

The extract below appeared in The Victoria Express, 7 January 1885

About five and twenty minutes past ten on Monday evening the inhabitants of geraldton were startled - many from their slumbers - by a severe shock of earthquake. The shock appeared to travel from a north-easterly direction and was preceded by a peculiar subterranean murmur lasting some seconds. This was followed by a tremor of the earth, which shook buildings and their contents in a most alarming manner. The shock from its first premonitory murmur to its complete subsidence must have lasted fully twenty seconds: and was of exceptional severity. Walls rocked, and the casement and contents of rooms rattled loudly, and a gentleman informs us that his bird was thrown off its perch. It aroused almost everybody in the town and for a time caused considerable consternation. There was no electrical disturbances in the air, the night being clear, calm and chilly for the time of year. Shortly after the shock, the sea subsided fully three feet in a quarter of an hour, but there was no subsequent rush of tide, the water rising gradually. According to the cable news we publish in another column the earth appears to have been in a state of great disturbance during the last few days in Europe, and we anticipate receiving further intelligence of a very heavy earthquake in some part of the world not very remote from ourselves.

Further particulars are to hand concerning the shock, and we learn from one of the men in charge at Point Moore Lighthouse that the shock was so severely felt there that he was almost thrown off his feet. Mr. du Boulay informs us that the shock was felt with much severity at his residence at Woorrie. A correspondent at Northampton telegraphs to us that the houses in the town were violently shaken and that a number of people were greatly frightened but no damage was done. The shock does not appear to have been felt at the Gascoyne as our Carnarvon correspondent reports nothing unusual has occurred here and the weather is fine and considering the season moderately cool. Up to the time of going to press we have received no information from Perth as to whether the shock was felt there.

Another event in the same general area was reported in May 1885. Everingham & Tilbury (1972) estimated a magnitude of 4 for this event, but, from the severity of the reported shaking, magnitude 5 might be a better estimate

From "The West Australian" of 11 May 1885

A very heavy shock of earthquake took place at six o'clock this morning and
lasted fully three quarters of a minute, in the direction of East to West.
Persons were thrown from one side of their bed to the other, houses rocked
violently and the disturbance altogether was on an extraordinary and alarming
kind. The weather was very overcast and threatening. It is reported from
Greenough that the shock was very heavy there, displacing plaster at the police
station. Giles of the eastern valley reports that his house rocked
tremendously and was nearly thrown down.

Some other earthquakes of interest are

28 August, 1917 Kalgoorlie

A tremor was reported near midnight, which resulted in an underground rock fall, killing one miner, and injuring several others.

20 April 1946, Yallingup

A magnitude 5.7 earthquake occurred near Yallingup at 2113 hrs on 19 April 1946 ( 05:13 local time on 20 April) , which was felt at Kirup. A tremor was reported at 05:30 am at Caves House Yallingup and at Busselton on 30 April, which is probably the same event, reported on the wrong date.

Gabalong, 30 August 1955, Mag 5.8

This earthquake was centred on Gabalong, a small community about 30 km east of Moora and 200 km NNE of Perth. The earthquake, at 9.52 pm local time, was felt at MM VI at Yericoin and Miling, and MM V in Moora. It was felt in Perth at intensities between MM II and MM IV, and at Dongara at MM II. It was preceded by a magnitude 5.3 earthquake at the same location at 2.09 pm on the same day. It was a SouthWest Seismic Zone earthquake, and because of the poor location capabilities at the time, may well be related to a series of earthquakes near Yericoin, which started with a magnitude 5.1 earthquake on May 2nd, 1949.

Busselton, 3 October 1959

A magnitude 5.0 earthquake occurred at 12:07 GMT (8.07 pm local time) at 34.5 degrees south, 114.5 degrees east. It was felt at Busselton, Yallingup, Margaret River, Bunbury, Cape Naturaliste and Cape Leeuwin.

Near Brookton, 18 Jan 1963

This earthquake occurred at a locality near Nourning Spring, approximately 20 km NE of Brookton and approximately 100 km ESE of Perth. It was felt at Intensity VII at Nourning Springs, VI at Brookton, and MM II at Perth. It occurred at 13:49 hrs local time, and had a magnitude of 5.4, although it was given a magnitude of 4.9 originally. Many earthquake questionnaires were distributed for this event, and a good isoseismal map was prepared.

Lake Tobin, 24 March 1970, Mag 6.7

This earthquake, near Lake Tobin in the Canning Basin, was the first in a location which had many more earthquakes over the following years. In all, there were three earthquakes of magnitude 6.0 or more (24/3/70, M 6.7, 16/7/71, M6.4 and 3/10/75, M 6.2), and 25 earthquakes of magnitude 5.0 or more, the last of which occurred on 13/2/1982

Cockatoo Sound, 10 Aug 1998, Mag 6.3

This earthquake, just off the WA north coast, was the largest Australian earthquake since the magnitude 6.7 earthquake near Tennant Creek, in the Northern Territory, in January 1988.

South of Albany, 12 Dec 2001, Mag 7.1

This very large earthquake occurred about 1000 km southeast of Albany. It was felt in Albany. It was an intra-plate earthquake, as it occurred about 1000 km north of the (constructive) boundary between the Indo-Australian and Antarctic plates.

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Important Historical Earthquakes in Western Australia