What are the indicators of a tsunami

Earthquake prediction

According to the current state of science and technology, there is no reliable method for forecasting earthquakes. Researchers are aware of some evidence that suggests an increased earthquake probability. However, these allow neither an exact location nor a temporal prediction. Earthquakes are and will remain natural phenomena that are difficult to predict for the time being.

Warning systems for earthquakes and tsunamis

However, it is physically possible to warn the population that the earthquake has already started. This technology takes advantage of the fact that an earthquake emits two different waves: first the harmless ones Primary waves (P waves), then the destructive ones about half as fast Secondary waves (S waves). If a seismograph registers a P-wave, it can trigger an alarm and warn of the next S-wave. Such warning systems are already in use. The achievable lead time depends on the distance to the earthquake focus and is in most cases only a few seconds.

The hope is that a few seconds can be enough to save lives. For example, people can step out of their homes to avoid being hit by falling walls. More about the correct behavior in case of earthquakes here.

The chance of a successful Early warning of tsunamis is much better. Although tsunamis also spread at high speeds (around 800 kilometers per hour) in the oceans, the earthquake waves are much faster. If a submarine earthquake is detected, the tsunami risk can be calculated on the basis of this data. In a favorable case, the authorities even have several hours to warn and evacuate the population. Many countries such as the USA, Japan, Indonesia, Taiwan and Malaysia already have a network of warning stations.

Apparently that is particularly successful and safe GPS technology, which indirectly registers fluctuations in the sea floor. Buoys and special pressure sensors are also in use on the sea floor, which are supposed to provide important data shortly after a seaquake.

Animal behavior as a warning signal

Some eyewitnesses report abnormal animal behavior shortly before an earthquake. For example, animals are said to have gathered in unusual places. According to some observers, the animals revealed something like a "sixth sense" that warned them of earthquakes. Therefore, there is always advice to take such unusual behavior seriously as a warning signal. However, so far there has been no scientific confirmation of this hypothesis.

Seismic calm

Other indicators, on the other hand, are more reliable and verifiable. For example, it has been found that the noble gas radon increasingly escapes from the earth before a major earthquake. In addition, there is something comparable with earthquakes like the "calm before the storm": If the otherwise frequent small earthquakes are absent for a long time in a typical earthquake region, the probability of an impending major quake increases. It is assumed that small earthquakes reduce the tension between two clods of earth and that a "seismic calm" leads to a build-up of tension. But even this model cannot say whether or when a major quake is actually to be feared.