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Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs. Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big. Environment As the EU targets emissions cuts, this country has a coal problem. How do tsunami differ from regular waves? What causes tsunami? Earthquakes Most tsunami are caused by large earthquakes on the sea floor when slabs of rock move past each other suddenly, causing the overlying water to move.
The largest run-up resulted from the Java tsunami that was recorded at 7. The tsunami that reach the Australia coast at Steep Point on 17 July was generated by a magnitude 7. The tsunami caused widespread erosion of roads and sand dunes, extensive vegetation damage and destroyed several campsites up to metres inland. The tsunami also transported a 4WD vehicle ten metres. Fish, starfish, corals and sea urchins were deposited on roads and sand dunes well above the regular high-tide mark.
Further north in the Onslow-Exmouth region in June , tsunami waves travelled inland to a point four metres above sea level and washed metres inland after appearing out of a calm sea. Both tsunami were generated by earthquakes in Indonesia. In May , a magnitude 9. The event generated tsunami waves of just under one metre at the Fort Denison tide gauge in Sydney Harbour. The tsunami in northern Papua New Guinea was caused by an earthquake that is believed to have triggered an undersea landslide.
The eruption of Krakatau volcano in Indonesia unleashed a series of devastating tsunami that resulted in the loss of tens of thousands of lives. What is Geoscience Australia's role in reducing risk to Australians from tsunami? Geoscience Australia: develops an understanding of natural hazards and community exposure to support risk mitigation and community resilience provides authoritative, independent information and advice to the Australian Government and other stakeholders to support risk mitigation and community resilience maintains and improves systems for effective natural disaster preparedness, response and recovery contributes to Australia's overseas development program.
Geoscience Australia identifies and characterises the triggering source for a tsunami to initiate the tsunami warning chain supports international efforts for the Indian Ocean tsunami warning and mitigation system IOTWMS.
In particular, the JATWC is one of three official Regional Tsunami Service Providers TSP for IOTWMS contributes data to the Pacific Tsunami Warning System for tsunami warnings in the South West Pacific develops national-scale offshore hazard maps as a fundamental input to assessing the local tsunami hazard and impact assesses the potential impact of tsunami on coastal communities in collaboration with state and territory emergency services supports national efforts to manage the potential impacts of tsunami, for example through participation in the Australian Tsunami Advisory Group ATAG collaborates nationally and internationally to enhance the tsunami hazard risk modelling methods.
Roles in the JATWC Geoscience Australia's role in the JATWC is two-fold: to detect earthquakes that have the potential to generate tsunami that can impact Australia's coastline, and advise the Bureau of Meteorology of this potential within 10 minutes of the earthquake occurring to undertake tsunami risk studies to assist local and state organisations in planning for tsunami events. Estimates of the earthquake magnitude and location are revised hourly or as more information becomes available, and this updated information is broadcast to authorities and the media.
The information continues to be reviewed as the first waves reach the shoreline, helping to provide better wave height estimates for countries further from the earthquake epicentre. At the local level, responses differ from country to country but the warning messages are usually broadcast through media channels including television, radio and internet.
Many people will also receive information through social media. Some countries send alerts directly to cell phones, and tourist areas may have tsunami sirens on popular beaches. Responding quickly and appropriately to these alerts can save lives. Fortunately on this occasion the tsunami triggered was only small. But the human impact of the earthquake itself is high, and the death toll will probably get worse.
Big tsunamis usually begin in the deep ocean, where a large volume of water can be displaced. As the wave moves closer to the shore, it grows taller as the ocean becomes shallower. If the water recedes—or moves away from the coast—after an earthquake, a big tsunami may be on its way.
This video shows how a tsunami can form from an earthquake under the ocean. Credit: NOAA. Tsunamis can be hundreds of feet tall, and they travel very fast. This means they can be dangerous even for people who aren't on the beach. Tsunamis can be extremely destructive and can knock down whole buildings. But not all earthquakes or volcanic eruptions cause tsunamis.
Whether a tsunami forms can depend on a lot of things. The shape of the ocean floor can determine if a tsunami happens.
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