Are submarines safe from a tsunami?

Tsunamis - mysteries of the deep sea

Almost invisible at sea

Not only the strength of an earthquake decides on the formation of a giant wave, several factors have to come together. Anyone wishing to warn of a tsunami must know how it occurs. And there are still some puzzles to be solved. If it has shaken, the researchers analyze the process and then use submersible boats to search the seabed of the affected regions for unusual features.

If a giant wave forms, it races through the ocean almost invisibly at 700 to 800 kilometers per hour. It often covers thousands of kilometers to the nearest coast. The tricky thing about it: The wave remains almost invisible at sea. Often the water level only rises a meter, sometimes even less.

But near the coast, when the sea becomes shallower, the giant wave can rear up and destroy obstacles with tremendous force. There have already been reports of tidal waves up to a hundred meters high.

On December 26, 2004, a tsunami in the Indian Ocean with waves more than 30 meters high killed well over 200,000 people. The tsunami was triggered by an earthquake on the ocean floor. A functioning early warning system could possibly have saved many lives.

The tsunami is revealed on the sea floor

A tsunami can throw deep-sea fish onto the beach from a depth of more than 1,000 meters. That reveals how deep the force of a tsunami can reach. When a tsunami races through the sea, the pressure on the sea floor changes.

That is why deep-sea researchers install sensors here that constantly monitor the pressure. Sensors transmit their measurement data to a transmitter buoy via an acoustic signal, and they are sent directly to early warning centers via satellite.

There the data is automatically evaluated and also compared with other measurement data, such as seismic activity. If it becomes threatening, the system sounds an alarm. The Pacific has been monitored for around 50 years. The system there has never failed so far.

Indonesia has had such an early warning network since 2011 - built and developed in a joint effort by German and Indonesian engineers and geologists.