It starts with silence. The kind that feels eerie. The waves stop rushing in. The sea quietly retreats, pulling back as though it’s holding its breath. Fish flip helplessly on the sand. Curious beachgoers walk closer, drawn by the mystery. But what they don’t realise is that nature is winding up like a slingshot. And when it lets go — it’s not water that flows, but a wall of fury. That’s a tsunami.
The word tsunami comes from Japan — tsu meaning harbour and nami meaning wave. But this wave doesn’t come with a warning bell. It often begins deep beneath the ocean floor, where massive rocky slabs called tectonic plates lie like pieces of a planet-sized puzzle. These plates are always on the move, nudging each other slowly. But sometimes, one plate slips suddenly beneath another — and the earth shakes.
When this happens under the sea, it’s not just the ground that moves. The entire water column above it is jolted. Imagine tapping the bottom of a full bucket — the surface ripples instantly. Now multiply that on a scale so vast that a wave begins racing across the ocean, travelling faster than a jet plane. Out in the deep sea, it might only rise a metre or two — barely a bump. But when it nears land, that energy has nowhere to go but up.
By the time it hits the shore, it can tower several storeys high.
On December 26, 2004, this exact nightmare unfolded after a 9.1-magnitude earthquake struck near Indonesia. The resulting tsunami raced across the Indian Ocean, hitting Sri Lanka, Thailand, India, and 11 other nations. Coastal towns were flattened. People were swept away. In just a few hours, more than 2 lakh lives were lost. India’s own eastern coast and the Andaman and Nicobar Islands felt the full brunt. It remains one of the deadliest natural disasters in human history.
But here’s the strange thing: not all tsunamis are caused by earthquakes. Underwater volcanic eruptions, landslides, and even meteorites slamming into oceans can trigger them. In 1958, a rockslide into Alaska’s Lituya Bay unleashed a tsunami that surged over 500 metres high — taller than most skyscrapers today. Trees were uprooted from hilltops. Boats vanished. It was nature at full volume.
Yet amidst the terror, there are tales of survival and quick thinking. Just before the 2004 tsunami reached Thailand, a young girl named Tilly Smith noticed something odd. The sea had pulled back — just like in a geography lesson she’d learned in school. She warned her family and the hotel staff. Dozens of people made it to higher ground because she connected the dots in time.
That’s the thing about tsunamis: the signs are subtle, but they’re there. The ocean withdrawing dramatically. A strange roaring sound. Animals fleeing inland. One wave might arrive gently, but it’s often just the first — more powerful waves usually follow. Waiting for “normal” to return can be a deadly mistake.
To stay ahead, many countries have built early warning systems. Underwater pressure sensors. Seismic monitors. Satellites. The moment a seaquake is detected, alerts are sent out — giving people precious minutes to escape. Japan, one of the most tsunami-prone places on Earth, even has old stone markers warning: “Do not build below this point.”
Long ago, an ancient Greek city named Helike vanished overnight, swallowed by a tsunami. It was lost for centuries, buried under layers of mud. In modern times, we have the tools to understand what happened — and to prevent history from repeating itself.