Find out how the global network of tsunami warning systems works

News of a Russian earthquake and tsunami* warnings dominated world headlines on Wednesday. The media has an important role to play when such events unfold: reaching as many people as possible before a potential tsunami hits gives them more time to prepare and respond.

In this case, the Pacific Tsunami Warning Centre (PTWC) added Australia to its advisory after the magnitude* 8.7 earthquake struck off the coast of Kamchatka in Russia’s east at about 9.24pm AEST, triggering tsunami warnings across the globe. It was the world’s largest recorded earthquake since 2011.

Russia and Japan were the primary focus of the tsunami warnings and both were hit by waves caused by the quake. The alert also took in Hawaii, parts of the west coast of North and South America, Alaska, parts of South East Asia, Guam and all Pacific Islands.

The PTWC said waves reaching 0.3 to 1m were possible along the Australian coast but a Bureau of Meteorology* spokesman said there was no tsunami threat here.

“The Joint Australian Tsunami Warning Centre has assessed the event in the Pacific and there is no threat current to the Australian mainland and islands,” they told NewsWire.

“The JATWC will continue to monitor and assess the situation as it evolves.”

AUSTRALIA IS AN ISLAND CONTINENT – ARE WE IN DANGER?
It is important to understand that, in general, Australia is in a very stable location. We are located in the middle of a continental plate and away from major fault lines*. We’re also part of an international network, sharing data, resources, response protocols and usually humanitarian aid to help countries when a tsunami strikes. Tsunami management is a global effort.

BUT WHAT ABOUT THE PACIFIC “RING OF FIRE”?
Yes, Australia is very close to the Pacific “Ring of Fire”. Hugging the edges of the Pacific Ocean, the ring takes in 452 volcanoes, from the southern tip of South America, up the coast of North America, across the Bering Strait, down through Japan and into our close neighbour New Zealand. National Geographic notes that there are even several active and dormant* volcanoes in Antarctica, which “close” the ring.

With that number of volcanoes, it’s no surprise that the ring is the source of 75 per cent of the world’s volcanoes and 80 per cent of its major earthquakes.

HOW DO EARTHQUAKES CREATE TSUNAMIS?
Tsunamis begin offshore after an earthquake, volcanic eruption or landslide. The sudden movement on the seabed displaces* the water above it. The upward movement might be less than a metre but it covers a very large area, so the total volume of water involved is huge. Unfortunately, there is no way of stopping it.

The Bureau of Meteorology said tsunamis that start in the Pacific or Indian oceans can approach Australian coastlines at the speed of a passenger jet, taking as little as two hours to reach our shores. That’s pretty fast – and we’re surrounded by water on all sides. But Australia is also part of a global tsunami early warning system network.

Tsunami warning systems and processes worldwide were overhauled following the devastating loss of life caused by the 2004 Boxing Day tsunami. Approximately 230,000 people across 14 impacted countries lost their lives, including 26 Australians. Even so, the 2011 Japan tsunami also claimed nearly 20,000 lives.

TSUNAMI WARNING NETWORK
Today, the Bureau of Meteorology and Geoscience Australia run one of the world’s most advanced tsunami warning systems.

The Joint Australian Tsunami Warning Centre (JATWC) provides 24/7 monitoring, detection and warning services for Australians. The centre’s tsunami warning services rely on three very special pieces of technology.

DETECTION BUOYS
Not your average bright bobbing buoy at the beach, these detection buoys have a big job to do.

Australia has a network of six deep-ocean tsunami detection buoys that make up not just the backbone of Australia’s ocean monitoring but also form a critical part of global monitoring in the Indian and Pacific oceans.

Like divers, they work in pairs. They’re located in three earthquake hotspots: the Indian Ocean, close to the Sunda Trench; the Coral Sea, on the edge of the Pacific Plate and the south Tasman Sea, close to the Puysegur Trench.

The Bureau of Meteorology site states that the buoys are extremely accurate.

Any sea-level changes caused by tsunamis trigger instant alerts. The buoys measure changes in deep-ocean sea levels as small as 1mm – but did you know that tsunamis actually build in shallow water? That’s why people who were on offshore boats during the Boxing Day tsunami were actually safer than those on the beach.

The buoys don’t come cheap. Not only are they huge – they look a bit like the space shuttles that bring NASA astronauts home with a splash – each buoy costs more than $1 million to build and deploy, and their exposure to heavy weather creates huge maintenance costs. But they’re money well spent, being our first and best defence.

WHAT ARE THE OTHER TWO PARTS OF THE SYSTEM?
Tide gauges and computer software are the other key components of the system. The Bureau has tide gauges attached to coastal piers and jetties around Australia, our offshore islands and in our 14 partner countries in the Pacific. Data from the gauges and buoys is updated every minute through JATWC’s phone and satellite network. Those 60-second updates are added to real-time data servers linking hundreds of other gauges and buoys across the world’s oceans, and exchanged freely in real time between countries.

There have been monumental advances in science and technology since 2004. The Bureau’s cutting-edge computer modelling software is key to predicting tsunami threats and evaluating the need for warnings.

A powerful supercomputer uses an earthquake’s location, depth and magnitude data to model how much water could be displaced by the sea floor movement and where it is then likely to travel. The speed and precision of the supercomputer means the Bureau can create a vast store of tsunami scenarios from all possible major undersea earthquake sources around the globe.

Most earthquakes pose no tsunami threat to Australia, and JATWC will issue a national No Threat Bulletin when it assesses the threat to be either non-existent or negligible.

On average, JATWC issues No Threat Bulletins about once a week. That means they’re fully aware of large earthquakes happening around the world and reassuring Aussies that there’s no threat to us.

If modelling indicates a potential threat, JATWC immediately issues a Tsunami Watch for relevant areas of the Australian coastline. It will then monitor its ocean and coastal networks to see if a tsunami has developed, how dangerous it is and where it is heading.

If a tsunami is confirmed or the threat is within 90 minutes of Australia, the watch will be upgraded to a warning, updated hourly and detailing which coastal zones are under what specific level of risk.

As soon as JATWC confirms a tsunami threat, the Bureau contacts emergency services.

The warnings are also delivered to other relevant authorities and organisations, such as port and maritime authorities, the Department of Defence, Surf Life Saving Australia, the Australian Maritime Safety Authority and media. JATWC also advises national tsunami warning centres around the Indian Ocean rim.

The Bureau also has a dedicated tsunami hotline (1300 TSUNAMI) and more information on JATWC and the Australian Tsunami Warning System can be found at: bom.gov.au/tsunami

The JATWC information in this explainer was sourced from the Australian Bureau of Meteorology site

POLL

GLOSSARY

• tsunami: an extremely large wave caused by a strong, sudden movement of the earth under the sea
• magnitude: size or extent
• fault line: also called a fault plane in geology, a fault line is the surface of a fault fracture along which the rocks have been displaced
• dormant: quiet and inactive, often used to describe a volcano that hasn’t been erupting
• displaces: to force something out of its usual or original position

EXTRA READING

Why some buildings fall in quakes

Biggest Taiwan quake in 25 years

Time capsule of the day the dinosaurs died

QUICK QUIZ

1. What was the magnitude of the earthquake that struck off the coast of Russia on July 30?
2. What does PTWC stand for?
3. Aside from Russia, the tsunami alert took in which other countries?
4. What proportion of the world’s volcanoes are located in the Pacific “Ring of Fire”?
5. What happened on Boxing Day, 2004?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Do you know?
Do you know if all earthquakes cause tsunamis? Use information from the story and possibly your research skills to find out. Use the information that you have found to create a set of diagrams that will help other kids understand the answer to this question.

Time: allow at least 60 minutes to complete this activity
Curriculum Links: English, Science, Geography, Visual Communication Design

2. Extension
“If most earthquakes don’t cause tsunamis in Australia, we shouldn’t waste money on a warning system!” Write paragraphs that would convince someone who believes this statement to change their mind. Use information from the story to help you.

Time: allow at least 25 minutes to complete this activity
Curriculum Links: English, Science, Geography

VCOP ACTIVITY
Wow word recycle 
There are plenty of wow words (ambitious pieces of vocabulary) being used in the article. Some are in the glossary, but there might be extra ones from the article that you think are exceptional as well.

Identify all the words in the article that you think are not common words, and particularly good choices for the writer to have chosen.

Select three words you have highlighted to recycle into your own sentences.

If any of the words you identified are not in the glossary, write up your own glossary for them.

Extension
Find a bland sentence from the article to up-level. Can you add more detail and description? Can you replace any base words with more specific synonyms?

Down-level for a younger audience. Find a sentence in the article that is high level. Now rewrite it for a younger audience so they can understand the words without using the glossary.