Earthquakes cause tsunami panic, but little damage
By Karlis SalnaThu Oct 8 18:31:46 EST 2009
Thu Oct 8 07:31:46 UTC 2009
CANBERRA, Oct 8 AAP - More aftershocks are expected in coming days after a series of powerful earthquakes triggered a tsunami alert for much of the South Pacific, including Australia's northeast coast.
The latest tremors caused panic on many of the region's remote islands just days after 184 people were killed when giant waves, whipped up by another earthquake, smashed into Samoa and neighbouring islands.
A warning was issued on Thursday by the Pacific Tsunami Warning Centre for some 25 countries and territories stretching as far as Australia, New Zealand and Indonesia.
The Joint Australian Tsunami Warning Centre issued a tsunami watch for areas off the north Queensland coast but cancelled the alert after more detailed analysis.
The first of three earthquakes struck about 500 km northwest of Vanuatu at 9.03am (AEDT), prompting thousands of people on remote islands to flee to higher ground.
Geoscience Australia said the large "potentially tsunamigenic" magnitude 7.9 earthquake occurred at a shallow depth of 38 km below the seabed and was followed by a series of strong aftershocks.
The two largest aftershocks were recorded at magnitudes of 7.4 and 6.8, occurring at 9.19am and 10.13am respectively.
However, the quakes produced only a small tsunami, with waves of just three to 10 centimetres recorded. Experts said serious damage was unlikely.
Geoscience Australia's senior seismologist, Dr Phil Cummins, said the absence of damage was not unexpected as the closest areas of significant population were outside the range of impact.
"Following this size earthquake we would expect to see a number of aftershocks in the coming days, and possibly weeks, gradually reducing in size and frequency", Dr Cummins said.
Authorities in Vanuatu said conditions around the archipelago were calm and that people in offices and resorts who moved to higher ground had since returned.
The Vanuatu Tourism Office said there was some minor structural damage on the island of Espiritu Santo but no reports of fatalities or injuries.
There were no reports of damage in the capital Port Vila or on Efate Island and there had been no effect on tourism operations.
Air Vanuatu said it would maintain normal services.
The airline's Australian manager, Malcolm Pryor, said he was not aware of anyone who had booked with Air Vanuatu cancelling their travel plans.
"Passengers that were booked today all elected to travel," he said.
The latest earthquakes follow those that impacted on the Samoa region and Indonesia last week. A 7.6-magnitude quake off the western coast of Sumatra killed more than 1000 people and left half a million homeless.
Dr Cummins said it was remarkable to have so many large earthquakes over such a short space of time, adding that while they were related as part of the Earth's ongoing dynamic processes, there was no direct connection.
"This earthquake occurred where the Australian plate slides beneath the Pacific Plate and releases stress which builds up due to this process," he said.
"Earthquakes will continue to occur at the boundaries of the Australian Plate as it pushes slowly northeast at approximately seven centimetres per year, resulting in collisions with the Pacific, Eurasian and Philippine plates."
