Australian Tsunami Warning System

Since the Indian Ocean Tsunami in December 2004, a number of countries around the world, including Australia, have increased their efforts to monitor, plan and warn for tsunami. The Australian Government, through the Bureau of Meteorology (the Bureau), Geoscience Australia (GA), and the Attorney-General's Department, (AGD) has been working with State and Territory governments and other relevant agencies to develop the Australian Tsunami Warning System (ATWS).

Joint Australian Tsunami Warning Centre

The Joint Australian Tsunami Warning Centre (JATWC) is jointly operated by the Bureau and GA. Based in Melbourne and Canberra, it was established in July 2007 so that Australia has the independent capability to detect, monitor, verify and warn the community of the existence of tsunami in our region and possible threats to Australian coastal locations and offshore islands.

The Bureau and GA are building on their combined expertise in the relevant science and technology areas including seismic and sea-level monitoring and a warning systems to provide 24/7 tsunami monitoring and analysis capacity for Australia. The centre boasts world class scientific technology with the expressed aim of providing the longest lead time of any potential tsunami threat. The major objective of the JATWC is to provide emergency managers with a minimum of 90 minutes warning of a likely tsunami impact on Australia. The Centre is a long-term investment in Australia's security and has the real potential to save lives and infrastructure.

Geoscience Australia Seismic Monitoring Station in Canberra.

Bureau of Meteorology staff provide early detection and warning for potentially dangerous tsunami.

Roles in the JATWC

The role of GA within the JATWC is to detect potentially tsunamigenic earthquakes in the Indian Ocean, Pacific Ocean and Southern Ocean, and advise the Bureau of this potential within 15 minutes of the earthquake occurring. GA also undertake tsunami risk studies to assist local and State organisations in planning for tsunami events.

The Bureau's role is to use its network of sea-level monitoring equipment including coastal sea-level gauges, deep-ocean tsunami detection buoys and tsunami computer models to confirm the existence of a tsunami and estimate its likely intensity at the Australian coast. The second part of the Bureau's role is to issue the relevant tsunami warnings and bulletins for Australia (including islands and territories) as required.

Distribution of messages

Media organisations across Australia work with the Bureau to inform the public in case of a tsunami event. Tsunami bulletins and warning distribution lists are maintained at each of the Bureau's State and Territory Regional Forecasting Centres.

These distribution lists are used for both National JATWC Bulletins and Regional Warnings. In addition to the media, key agencies such as the State and Territory emergency services, local councils, port authorities and police are included on these dissemination lists. The bulletin and warning messages are also automatically uploaded to the Bureau's website.

How does the new distribution system work?

GA operates an enhanced network of seismic stations nationally and has access to data from international monitoring networks. It advises the Bureau and AGD of the magnitude, location and characteristics of a seismic event which has the potential to generate a tsunami.

Based on this seismic information from GA, as well as advisories from the Pacific Tsunami Warning Centre (PTWC) in Hawaii, and from neighbouring countries with tsunami detecting capacity, the Bureau runs a tsunami model to generate a first estimate of the tsunami size, arrival time and potential impact locations. They then verify the existence of a tsunami using information from an enhanced sea level monitoring network.

The Bureau then promulgates advice and warnings on any possible tsunami threat to State emergency management services, media and the public. AGD liaises with the operations centres of affected State and Territory emergency management organisations and coordinates Federal assistance as required. AGD also has responsibility for improving public awareness and preparedness for tsunami in Australia.

Categories of threat levels within tsunami warnings

In order to assist the community, tsunami threat levels in regional tsunami warnings are categorised into three levels with required community responses. These have been determined in consultation with emergency management authorities. These threat levels will be specified for the same coastal areas that are used for routine Bureau Coastal Waters Forecasts, already known to marine users.

No threat
An undersea earthquake has been detected, however it has not generated a tsunami or the tsunami poses no threat to Australia and its offshore territories.

Marine and immediate foreshore threat
Warning of potentially dangerous waves, strong ocean currents in the marine environment and the possibility of only some localised overflow onto the immediate foreshore.

Land inundation threat
Warning for low-lying coastal areas of major land inundation, flooding, dangerous waves and strong ocean currents.

Cancellation of a tsunami warning

When the main threat has passed or if a tsunami didn't eventuate, the Bureau will issue a Tsunami Watch Cancellation or Tsunami Warning Cancellation. The relevant State or Territory emergency authority will inform the public when it is safe to return to the affected areas. However, caution should be exercised as unusual ocean activity may continue to affect beaches, harbours and coastal waterways hours and even days after an event.

For latest tsunami warnings call 1300 TSUNAMI (130 0878 6264) or visit the Bureau of Meteorology website at www.bom.gov.au

For tsunami assistance call SES on 132 500 (or if in Tasmania or Northern Territory police assistance on 131 444).