Is a megaquake coming to Japan? How ready is the country for it?

Japan has seen multiple earthquakes over the years. And on Thursday (August 8), it quivered once again when a powerful 7.1-magnitude temblor struck off its southern coast, sparking a tsunami advisory.

But following this temblor, the Japan Meteorological Agency (JMA) issued its first-ever megaquake warning, which has led to concern and worry among the Japanese.

What does this megaquake warning mean? And will Japan be able to survive it? If these questions are plaguing your mind, we have the answers.

Quake rattles Japan

On Thursday (August 8), a 7.1 magnitude earthquake occurred off the southern island of Kyushu, at a depth of about 18 miles. Japan’s Chief Cabinet Secretary Yoshimasa Hayashi said that three people were reported injured. However, the Fire and Disaster Management Agency said eight people were hurt — including several hit by falling objects.

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One resident in Kyushu was quoted as saying, “First time in my life I’ve felt shaking like this. Normally I barely feel it when I’m outside or in a car, but it shook to the point that even when I’m standing, there was a fluttering feeling.”

Footage from Japan showed light fixtures and wall decorations swinging as the earthquake struck the region. Broadcaster NHK also showed traffic lights shaking violently in Miyazaki on Kyushu’s southeast coast.

However, there was no major damage reported — reports stated that traffic lights and cars shook and dishes fell off shelves — with the chief secretary reporting that there were no blackouts or damage to the water or communications systems in the region.

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While Japan Rail did suspend bullet train services for a while as a precaution, there were no reports of abnormalities at the nuclear power plants after the quake.

Following the quake, officials also issued a tsunami advisory, warning residents to immediately leave the coastal areas of Kochi and Miyazaki prefectures until the warning is lifted. Tsunami waves of up to 1.6 feet were detected along parts of Kyushu’s southern coast and the nearby island of Shikoku about a half hour after the quake struck. Japanese broadcaster NHK said Miyazaki Port had reported a surge of 20 inches.

A megaquake warning

As people resumed their daily life after the 7.1-magnitude tremor, the JMA then issued a warning — the first of its kind — about an increased risk of a “major earthquake” striking in the near future.

In its warning, the JMA said that the risk of a massive earthquake occurring around the Nankai Trough that runs along the Pacific coast has become higher than usual. It added that in the worst-case scenario, a powerful temblor could shake a wide area of Japan — from the Kanto region centering on Tokyo to the southwestern Kyushu region — and high tsunami waves could engulf the coastal areas of Kanto to Okinawa.

Naoshi Hirata, the head of an advisory body to the weather agency that assessed the latest quake, also said the probability of a major earthquake along the Nankai Trough has now increased by “several times” compared to usual, reported Kyodo news.

The agency further clarified that the warning didn’t mean that a quake would definitely occur in the coming days. It also said that while it didn’t recommend evacuation, it called for reviewing routine quake preparedness and staying alert for about a week.

Earlier in 2012, experts had said that there is a 70-80 per chance of a magnitude 8 or 9 quake striking somewhere along the trough in the next 30 years, which could result in the deaths of more than 300,000 people.

A Reuters report adds that the damage from such an earthquake could be a total of up to 220 trillion yen ($1.50 trillion), or more than a third of Japan’s annual gross domestic product, with long-lasting impacts on infrastructure and supply chains for coastal industrial powerhouses producing cars and other key Japanese products.

And past quakes in the Nankai Trough seem to match this assessment. Earthquakes typically occur in the Nankai Trough every 100 to 150 years. The most recent being the December 1946 quake of 8.1 magnitude. It killed more than 1,300 people and the US Geological Survey noted that it destroyed more than 36,000 houses.

The major earthquake warning prompted Japanese Prime Minister Fumio Kishida to cancel a trip to Central Asia. He was expected to travel to Kazakhstan, Uzbekistan and Mongolia and had planned to attend a regional summit. However, the Japanese PM has rescheduled his travel plans, telling reporters: “As the prime minister with the highest responsibility for crisis management, I decided I should stay in Japan for at least a week.”

Japan’s preparedness to be tested

With the possibility of a megaquake striking Japan, the question to ask is — can the country withstand such a natural disaster?

Japan , which sits on the Pacific Ring of Fire and is familiar with large tremors, has learnt from the past and adjusted its standards for structural engineering and strictly enforces them. It all began back in 1923 when a 7.9-magnitude earthquake in Yokohama, Japan, killed 140,000 people and toppled hundreds of thousands of structures. Because many of the country’s older buildings were made of wood, they weren’t able to handle the tremors.

Hence, after the tragedy, the Japanese introduced seismic standards to its building codes, focusing on strengthening new and existing wood and concrete construction, particularly in urban areas. Since then, laws specify that all buildings in Japan must not collapse during an earthquake of any force, despite the amount of damage that they sustain during the quake. Architects and engineers can achieve this life-saving stability by using both reinforcing and isolating techniques.

To achieve this objective of a building being able to withstand seismic activity, buildings are fortified with thicker beams, pillars, and walls to better withstand shaking. There’s also the installation of pads made of absorbent material like rubber at the base of a building’s foundation, dampening the shock of movement to the structure itself.

Builders also use dampers , which swing like pendulums inside skyscrapers, in an effort to ensure that the tall structures are earthquake proof.

Miho Mazereeuw, an associate professor of architecture and urbanism at the Massachusetts Institute of Technology (MIT), who explores Japan’s culture of preparedness, told CNN: “Conceptually, it all comes back to the idea that, rather than resisting the movement of the Earth, you let the building move with it.”

Take for example, the Toji temple’s 180-foot tall pagoda, constructed in the 17th century near Kyoto, which emerged intact from the 1995 Great Hanshin earthquake, also known as the Kobe quake, while many nearby buildings collapsed.

Experts note that this pagoda, along with others, has been able to withstand powerful temblors because of “shinbashira” — central pillars made from tree trunks and used by Japanese architects for at least 1,400 years.

However, building safety is only one part of Japan’s resilience towards earthquakes. As University of Tokyo professor Toshitaka Katada told AP that he believes that there are “probably no people on Earth who are as disaster-ready as the Japanese”. Evacuation drills are taken very seriously and evacuation centres are equipped with emergency supplies, and residents are told to have emergency supplies available at their homes, as well. The country also has a robust warning system.

However, despite all the prep and planning; all the innovation and hard work, Japan’s engineers can’t say for sure if the country’s buildings will be able to stand tall if an earthquake. Robert Geller, professor emeritus of seismology at the University of Tokyo, told CNN: “Tokyo is probably reasonably safe. But there’s no way to know for sure until the next big earthquake actually happens.”

With inputs from agencies