Quirks & Quarks

Earthquake science takes great strides in the 10 years since massive quake hit Japan

10 years ago a massive earthquake struck off the coast of Japan, resulting in a massive tsunami, killing nearly 16,000 people. But it also became the best studied large earthquake in history thanks to the number of instruments that captured the event in remarkable detail.

The 2011 quake was so strong, the Earth started spinning faster and days were a microsecond shorter.

A woman prays at a memorial site for the victims of the 2011 Tohoku earthquake and tsunami. (Yuichi Yamazaki/Getty Images)

Ten years after one of the strongest earthquakes ever recorded — and the costliest natural disaster in history — the world's earthquake hotspots are safer because of the lessons learned.

On March 11, 2011, a magnitude 9.0 earthquake struck the Pacific coast near the Tōhoku region of Japan, triggering a tsunami more than 40 metres high, which surged up to 10 kilometres inland, destroying everything in its path. It killed more than 15,000 people, and left hundreds of thousands of people homeless, and caused a triple nuclear meltdown at the Fukushima nuclear power plant.

On the ground and undersea, recently installed observation networks captured the event in remarkable detail.

An aerial picture shows a view of the tsunami-devastated the town of Ishinomaki, Japan on April 1, 2011. (KAZUHIRO NOGI/AFP via Getty Images)

"It was really the first well recorded subduction earthquake anywhere in the world. There were well over a thousand instruments on Japan that recorded this earthquake, both seismographs and GPS," earthquake seismologist John Cassidy told Quirks & Quarks host Bob McDonald.

Those recordings allowed for detailed measurements of the types of forces exerted from a quake this large, which has helped inform researchers around the world, including in Canada. 

"We know that the same type of earthquake happens here. We've seen evidence for 19 of those in the past 10,000 years. But we don't have any recordings of the shaking because the last one was more than 300 years ago," said Cassidy, who is the head of the Earthquake Seismology Section at Natural Resources Canada.

In this photo from 2019, work continues on a seawall near one of the towns hit by the 2011 Tohoku earthquake and tsunami. Japan has spent around $12 billion on the construction of 245 miles of seawall along its north east coast. (Carl Court/Getty Images)

But now, thanks to the information from the Tōhoku earthquake, "we know the size of the earthquakes and we know what type of ground shaking to expect."

"So that information has been folded into our national building code and is being used today in the design of bridges and structures to make them more earthquake resistant."

You can listen to Cassidy's full interview with Bob McDonald at the link above.

Written and produced by Amanda Buckiewicz


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