Tsunami: What are they and how are they?
On Tuesday, a powerful 8.8 magnitude earthquake shook the area around Russia’s Doodle Peninsula, resulting in a tsunami warning worldwide. From Hawaii to Chile and Australia from Hawaii to Japan and BC coast, people were warned that high water could provoke their beaches.
Many people remember the deadly 2004 boxing day tsunami, which occurred after a 9.1 magnitude earthquake on the banks of Sumatra, Indonesia. More than 280,000 people died, and over a million people were displaced in South Asia and East Africa.
Another memorable and tragic earthquake and tsunami were the Tohoku incident in 2011, forcing Japan’s Fukushima nuclear power plant to shut down and killed over 15,000 people.
Clearly, tsunamis occur, but how many times and how dangerous they can be? There are some tsunamis facts here.
Large waves were observed on Wednesday as they reached the banks of Hokkaido in Japan after a powerful 8.8-distance earthquake in Russia.
What is tsunami?
The answer is less simple than some imagination.
Most people think of a tsunami that is in the form of a large wave that reaches a beach. But a tsunami is actually a series of waves, which arises from the displacement of water in the sea. It can increase the water level from centimeter to tens of meters and wash homes, buildings and people.
Tsunami waves travel in all directions and can proceed to an entire ocean basin – as we saw with a doodle earthquake on Tuesday, which traveled far from northern Pacific to South Pacific to New Zealand.
And they do not live just on the beach. They can travel to rivers and sections and stay for several hours or days as they are ahead in the basin of an ocean.
Earth’s tectonic plates are gradually shifted – about nine centimeters per year, slightly faster than nails. This movement can trigger powerful earthquakes. Earthquaker John Cassidi explains science behind the earthquake and why they can take the tsunami.
Catsu Goda, Associate Professor in Earth Sciences at Western University and Canada Research Chair in Multi-Haser Risk Assessment, said that it is liked that if you implicate your finger in a bowl of water, you will look at small waves, not only one wave.
What is the reason for tsunami?
Eighty percent of tsunami Earthquakes arise, but this is not their only source.
They can be due to landslides both above and below the sea. Rarely, they can be caused by atmospheric changes. These are called metiotsunamis. In fact, one is considered Superior is on lake Thunder Bay, near Onts in June.
Shunyah, Onts. Scientists say they feel that the video shows a metiotunmi, a type of large wave that can be caused by changes in atmospheric pressure.
Goda said underwater landslides can be triggered by relatively average earthquakes. The submarine landslides can expand to hundreds of kilometers, causing a large displacement of water that causes a tsunami that causes a tsunami.
It is also important to understand that while earthquake is a sub -center, it actually occurs for a hundred kilometers or more.
When they are in the sea, it is very displaced water.
How common are they?
Tsunami – Particularly large such as Sumatra and Tohoku events – are rare, Goda said.
“We think they (are) from at least a hundred years to a thousand years … for a place,” he said.
As Global Historical Tsunami DatabaseDangerous tsunamis occur about twice a year. Large tsunamis that cause damage or death of more than 1,000 kilometers occur about twice per decade.
Is Canada at risk?
When Tuesday’s tsunami warning was issued, they were involved Most of the BC coast,
The province is not a stranger for earthquake or tsunami dangers. This is because the south -western part of the province sits above the boundary between the Oceanic Juan de Fuka plate and the Continental North American plate. The border is called the Cascadia Sub -Division Zone and extends 1,000 km from North Vancouver Island to Northern California.
The earthquakes in the Cashedia subduction zone are called the megathrust earthquake, with a rupture region to the west of the Vancouver Island. It is the source of potential “Big forest” for BC, which is an earthquake with a magnitude of nine or more.
“Cashedia Sub -Division Zone, known as ‘The Big One’, is the one we must be ready,” said Goda. “If this happens, there are some things similar to tohoku or Sumatra. That’s what we hope, you know, 10 to 15-meters or even 20-meter will be on the tsunami coast.”
Brent Ward, co-director of the Center for Natural Hazars Research, says that an international network is to determine the risk of a tsunami, sometimes within a few minutes of earthquake. On Tuesday, BC issued several tsunami advice after a major earthquake in the Pacific Basin near Russia.
According to natural resources Canada, these earthquakes occur in about 200 to 800 years. And if there was “big one”, there would have been a difference of only 15 to 30 minutes between the earthquake and the first tsunami waves.
But there is also the eastern coast.
Although the Pacific is not almost active as the “ring of fire” of the Ocean-an area of a 40,000-km horseshoe-shaped area which is known for seismic activity-is a mistake in the middle of the Atlantic Ocean.
In fact, in November 1929 there was a 7.4 earthquake of magnitude, which led to a landslide in the sea, resulting in a tsunami Waves of three to seven meters In Nova Scotia. In Newfoundland, the waves reached 13 meters.
Goda said that when there is no way to stop the tsunami, it is important to have a good warning system in the place.
It seemed that this was the case with the most recent earthquake and tsunami.
“I think it is very difficult to stop the wave itself, it’s just like – in my opinion – huge energy,” he said.
“I think the only solution to save people’s lives is withdrawal. So initial warning is important, and tsunami withdrawal training is important, and there should be a place that people can vacate.”
