Yes but huge tsunamis - 'megatsunamis' - are not caused by undersea earthquakes, especially half a world away off Chile. They are caused by volcanic eruptions, or meteor/asteroid impacts. The Krakatau eruption in 1883 made much larger tsunamis - upwards of 50m high - than the undersea Boxing Day earthquake, the second-largest earthquake ever recorded.
The only eruption that could cause megatsunamis on the Australian east coast would be a cataclysmic eruption in New Zealand, such as the one that blew out Lake Taupo around 26,000 years ago (Lake Taupo is the volcano's caldera). We should worry - Taupo historically erupts every 1,000 years or so but hasn't done anything since 1800 BC. It's overdue, and apparently the average temperatures of the waters of Lake Taupo are gradually increasing - perhaps the volcano is warming up again.
One interesting theory is that a tsunami was the basis of the Moses crossing the Red Sea story. The Santorini volcano in the Mediterranean Sea erupted in 1628 BC, one of the largest volcanic eruptions in recorded history. It's also known as the Minoan, or Thera, eruption. It destroyed the Minoan civilisation on Thera, was recorded in Greek myths and caused low temperatures, crop failures, and spectacular sunsets in China. It also sent 100m high tsunamis across the Mediterranean, devastating the coast of Egypt. That was roughly the time of the Exodus of the Israelites from Egypt mentioned in the Bible. Mosus supposedly parted the sea - the tsunami would have caused the shoreline to draw back - got safely across but the following Pharaoh's army was swamped as the water returned. Just like a tsunami.
Exactly Phil74.
The pillar of fire by night and the column of smoke by day that was used by Moses to navigate the Children of Israel out of Egypt is said to have been followed. This would not be correct as it was to their North as they traveled to their North East, but it would have been a very useful navigation aid. It was of course the Thera volcano going gangbusters with smoke and ash that would have lit up the whole sky at night and would have put up a huge column of smoke by day that would have been easily seen even though it was over the horizon.
I'm one of the people who got the media to stop calling the Boxing Day Tsunami a tidal wave. I telephoned every TV station in Perth and got right up them for their irritating ignorance about the differences between tsunamis and tidal waves. I wasn't the only one who was doing that. By the second day, the TV stations were saying that they had got the message.
There is a diference between a tsunami and a tidal wave, but the average bloke in the street wouldn't know it and what difference would it make if a bloody great wall of water came roaring over the piece of land that you happened to be standing on at the time, being one of the older generation I had never heard of a tsunami till fairly recently, they were always tidal waves to me, still I'm glad you got your message across.
I dream of a day when a chicken can cross a road without being asked for it's motive!
Without going into long and involved detail a tidal wave is caused by the moon which causes tides and they occur every 12 hours. Tidal waves or tidal bores occur in only a few places like the Bristol Channel and The Bay of Fundy were the water is channeled into a narrow space. Broome does not have a tidal wave. It comes in at a steady rate but not as a big wave because it's an open ocean beach front.
A tsunami is caused by earthquakes under or near the ocean, volcanoes blowing up and taking the whole mountain with it in a big bang and creating a caldera, under or near the ocean or meteorites hitting the ocean.
To the everyday observer the most important indicator of a tsunami about to strike is that the ocean recedes in an unusual event and then comes rushing back in as a huge wave.
That's what happened in the Boxing Day Tsunami. The ocean went out and people went out to look at the sea bed instead of doing what the elephants did and running for high ground. The elephants knew what was about to happen and took off at the run ignoring all commands to stop.
A tsunami travels across the ocean at about 600 miles per hour. It's not a wave as in water moving bodily, but it's a pressure wave. Deep ocean islands that have deep water all around do not have tsunamis. Ships on the ocean do not even notice the tsunami pressure wave going past. Ocean fronts with shelving beaches have tsunamis.
The key to it is the water goes out first and then it comes rushing back in, so if you are ever at a beach and the water goes out in an unusual way, get out of there in a big hurry. Head for the hills or climb high in a very strong building.
