Seismicity of Western Australia - Tsunamis in Western Australia

At least four tsunamis are known to have affected the Western Australian coastline in the last 50 years. By far the most significant was the event of Decemeber 2004.

They have all resulted from large earthquakes in the Indonesian region. These earthquakes are tabluated below

DATE	Mag	Latitude	Longitude	Remarks
17 August 1977	7.9	11.09 S	118.46 E	6 m wave at Cape Leveque
3 June 1994	7.2	10.48 S	112.83 E	flooded carpark near Exmouth
26 December 2004	9.0	3.30 N	95.78E	affected entire WA coastline
17 July 2006	7.7	9.31 S	107.28 E	2.5 m waves at Steep Pt.

The most recent tsunami event in Western Australia was on 17 July 2006, and came close to drowning some sea-side campers in the the Shark Bay region.

People who have first-hand accounts of the Dec 2004 tsunami, particularly its effects in Australia, are encouraged to report the effects by going to this report form, or sending an email to vdent@cyllene.uwa.edu.au

Map showing locations of three earthquakes and a volcanic eruption (Krakatoa) which have caused tsunamis in Western Australia

July 2006

The report below appeared in The Western Australian on 19 July 2006

Tsunami surge hits North-west campers

A Rockingham family ran for their lives after two metre waves caused by the Java earthquake devastated their Shark Bay campsite on Monday night.

Andrew White was preparing dinner at 7.30 pm on the beach next to his family's camp site at Steep Point, when an unusual sound caught his attention.

He saw two monster waves then ran 6 metres up the beach yelling to his partner who was about to put their 14 month old baby girl Kyra into a tent.

The family, including sons Luke, 10 and Jayden, 12 and friends at a nearby camp ran to higher ground, just escaping the chest-high water that flowed through their camp.

In most of northern Western Australia, sea leavels rose 10 - 20 cm. Dampier salt reported a 42 cm rise. Exmouth had rises of 30 - 40 cm.

Below - camp site at Steep Point, the next day. Photo by Paul Dickinson

The site at Steep Point was surveyed by geoscientists from Geoscience Australia shortly after the event. For more information, contact Amy Prendergast or Nick Brown at Geoscience Australia www.ga.gov.au

Boxing Day Tsunami, December 2004

Because of the significance and amount of information about this tsunami, most reports of its effects in Western Australia have been moved to a separate page.

EARTHQUAKE of 3 June 1994 (1817 GMT, 2 June), Mag 7.2

Earthquake location : -10.477, 112.83

A magnitude 7.2 earthquake struck Indonesia at 1817 hours, GMT on 2nd June, 1994. This event generated a large tsunami, which claimed over 200 lives along the Indian Ocean coast of Java.

The tsunami reached the north west coast of Australia 3 to 4 hours later, in the early morning of 3 June, and was recorded at Broome, Carnarvon, King Bay and Onslow. The wave carried fish, crayfish, rocks and coral inland for a distance of two to three hundred metres. It was heard by some residents of a caravan park as making a roaring sound, like a train.

An eyewitness at Onslow said that from a calm sea she saw two large waves appear, the second of which was estimated to be two to three metres high.

Report taken from "The West Australian" newspaper, 4 June 1994

Big waves dump fish, hit boats in Exmouth

TIDAL waves smashed fences and sign posts, beached small boats, washed away a road and left thousands of fish, squid and other sea life stranded hundreds of metres inland near Exmouth between 5am and 6am on Friday.

The three tidal waves were whipped up by an earthquake measuring 7.2 on the Richter scale that rocked the east coast of Java.

Exmouth police Sgt Neil Blair said the tidal waves would have caused a tragedy during the tourist season of if they had hit further north where fishing trawlers were moored.

Chris White, manager of the Yardie Creek Homestead caravan park south of Exmouth, said the waves left thousands of fish, crayfish and giant clams scattered in the sand dunes and in a carpark.

"One fellow got up early and went down to go fishing" Mr White said.

"He found hundreds and hundreds of fish on the beach. He threw about 300 big fish back in before he came back to tell everyone."

Mr White said the waves had swept through a channel in the surrounding coral reef and into the Cape Range National Park

EARTHQUAKE of 19 Aug 1977 (0608 GMT) - Magnitude 7.9

Earthquake location : -11.085, 118.464

On 19 August 1977, a magnitude 7.9 earthquake struck Sumba Is. in the Indonesian archipelago. A tsunami was generated which claimed approximately 190 lives in the region. Later on Aug 19, a tsunami was recorded at Cape Leveque, which reached 6 m vertically above the normal high tide mark.

Earlier Tsunamis

Two tsunamis are known to have affected Western Australia in the late 1800's. Due to the low population at the time, it is quite likely that the coastline has experienced other events, but that they have gone un-reported.

GERALDTON, January 05, 1885

Ian Everingham, in a report on the Seismicity of Western Australia, published the following extract from a newspaper in Geraldton in 1885.

"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"

From the reported felt effects of the earthquake, Everingham estimated the location of the earthquake to be 29 degrees South, and 114 degrees East (ie, about 70 km west of Geraldton. Its magnitude was estimated to be 6.5 on the Richter scale, and it occurred at 1425 hrs GMT, or 10.25 pm local time.

This is the only tsunami known in Austrlalia to have probably originated from a relatively close earthquake.

Krakatoa Volcanic Eruption, August 1883

The massive volcanic eruption/explosion of Karakatoa Island, in the Sunda Straights region of Indonesia caused widespead local devastation. However, its effects in Australia are sketchy. Below is an extract from "The WestAustralian" newspaper of 31 August, 1883. It has also been reported that the sand dunes to the east of Ningaloo Reef were inundated by water for approximately 1 kilometre (source unknown).

Extracted from "The West Australian", Friday August 31, 1883

We received the following telegram from Geraldton yesterday Strange rumbling sounds were heard here and at Tibradden and elsewhere on Monday morning early, and a most unusual rise of tide took place on Monday evening at eight o'clock, and again at half eight. The sea receded over 100 yards, enabling people to pick up fish in quantities. The draw back was of short duration. The sea returned with a great rushing noise and those who were fish gathering had to run quickly for their lives. Boats that were high and dry on the beach were washed out and swamped. The Rob Roy and the lighters at anchor were twisted right around. The sea rose about eight feet. In a short time all was quiet again, except that the ocean continued rising and falling until next morning		.