Major earthquake triggers tsunami warnings in Taiwan, Japan

Japan downgrades tsunami warning after Taiwan quake

A major earthquake hit Taiwan's east shortly before 8:00 am (0000 GMT) local time Wednesday, prompting tsunami warnings for the self-ruled island as well as parts of southern Japan.

The United States Geological Survey (USGS) said the quake had a magnitude of 7.4, with its epicentre 18 kilometres (11 miles) south of Taiwan's Hualien City at a depth of 34.8 km.

Japan's Meteorological Agency put the magnitude at 7.5.

Tsunami waves as high as three metres (10 feet) were expected immediately for remote Japanese islands in the region, including Miyakojima island, the agency said.

"Evacuate!" said a banner on Japanese national broadcaster NHK.

"Tsunami is coming. Please evacuate immediately," an anchor on NHK said. "Do not stop. Do not go back."

Live TV footage from the Okinawa region's ports, including Naha, showed vessels heading out to sea, possibly in efforts to protect their ships.

Taiwan is regularly hit by earthquakes because the island lies near the junction of two tectonic plates.

A 7.6-magnitude jolt hit Taiwan in September 1999, killing around 2,400 people in the deadliest natural disaster in the island's history.

Japan experiences around 1,500 jolts every year.

The vast majority are mild, although the damage they cause varies according to the depth of the epicentre below the Earth's surface and its location.

The severity of tsunamis -- vast and potentially destructive series of waves that can move at hundreds of miles (kilometres) per hour -- also depends upon multiple factors.

Even larger quakes usually cause little damage in Japan and Taiwan thanks to special construction techniques and strict building regulations.

Japan has also developed sophisticated procedures and technology to alert and evacuate people when needed.

Japan's biggest earthquake on record was a massive 9.0-magnitude undersea jolt in March 2011 off Japan's northeast coast, which triggered a tsunami that left around 18,500 people dead or missing.

The 2011 catastrophe also sent three reactors into meltdown at the Fukushima nuclear plant, causing Japan's worst post-war disaster and the most serious nuclear accident since Chernobyl.

The total cost was estimated at 16.9 trillion yen ($112 billion), not including for the hazardous decommissioning of the Fukushima facility, which is expected to take decades.

Despite stricter building guidelines, many structures, particularly outside major cities, but not only there, are old and vulnerable.

This was brought home in the 7.5-magnitude New Year's Day quake in 2024, which hit Noto Peninsula and killed more than 230 people, many of them when older buildings collapsed.