It's one of the most devastating natural disasters imaginable. They cause enormous waves that sweep away everything in their path. Discover in this post the characteristics of a tsunami : what it is, its causes, consequences, and much more.
What is a tsunami?
It is said that a tsunami has been generated when a series of large waves can be observed. These waves are the product of strong movements in the earth's crust, which are found under the seabed.
These high-intensity movements on Earth can be caused by earthquakes, volcanic activity, such as that of the Kilauea Volcano , or rockfalls at the bottom of seas and oceans.
A tsunami originates from a series of tremors in fragments of the lithosphere. These oscillations occur in the benthic zone of bodies of water, and when they reach the maximum levels on their classification scale, they produce great tragedies, making them one of the most catastrophic natural disasters that can occur.
There are other characteristics of a tsunami, but the height of its waves will depend on the depth of the epicenter that originates it and the distance it has from the coasts.
Characteristics of a tsunami
A tsunami has several characteristics ; some of them are mentioned below:
- The waves that are produced reach a height of more than 40 meters. This is the equivalent of standing in front of a seven story building.
- In general, it is preceded by an earthquake, although it could be due to volcanic activities, also by the movements of the tectonic plates and in very rare cases, they can be triggered by the fall of a meteorite.
- In the areas farthest from the coast, the waves can reach speeds of up to 900 kilometers per hour. This acceleration is directly proportional to the depth of the body of water.
- One of the characteristics of a tsunami, which causes conflicting criteria, is the dramatic reduction in its speed when it approaches the coast. These drop to below 20 kilometers per hour.
- It is important not to confuse the terms tidal wave and tsunami, which are generally used as similar. In reality they are totally different phenomena, a tidal wave has its epicenter in the depths of the sea, while the tsunami is a large wave.
- The tsunami that exceeds 6 °, has devastating effects on all infrastructure and people who are close to the event. They have the power to destroy houses, crops, factories, among others.
- Rivers, lakes and other freshwater reserves are affected by the incorporation of water with high concentrations of salinity. In addition to the harmful effect, with the increase in the pH of arable soils and the rest of the ecosystems.
- Tsunamis are classified by their intensity and can range from I to VI on the Sieberg scale. Being grade I the one with the least intensity and grade VI, it can produce great natural disasters, like the ones that happened tsunami from Japan, Indonesia and Sumatra.
Causes of tsunamis
Tsunamis are usually the result of strong earthquakes, although other natural events can cause the formation of these huge destructive waves.
The triggering events for these natural disasters are listed below.
Earthquakes
The movements of the tectonic plates are usually the triggers for these colossal waves in series, which is one of the characteristics of a tsunami. The continuous elevation or descent of the plates causes a displacement of the masses of water above them, forming the great waves.
This wave formation of high proportions can move in different directions and without a pattern in size.
The earthquake, in order to cause the formation of a tsunami, has to occur in the depths of the ocean. In addition to generating a vertical movement in the water column, covering an area of more than 100 square kilometers.
In the place where the epicenter occurred, the waves are low. But as these masses of water approach the coast, where the waters are shallow, the waves reach enormous heights, which are what cause the worst flooding.
rock slides
The collapse of rocky material, when it is on a large scale and goes directly to the sea, can produce large waves. Once these waves reach the nearby coasts, they cause terrible flooding with the disastrous consequences of the deaths of people and the desolation of cities.
volcanic activities
Volcanic activity generally causes large explosions and expels large amounts of debris in the form of smoke into the air, if it occurs in the interior of a volcano.
But, if the activity is on the seabed, it can cause such a powerful displacement of the mass of water that they will quickly become large waves.
Wherever the tsunami originates from, it will always bring the loss of human lives, the collapse of the economies of the affected nations and the feeling of helplessness of their inhabitants.
Information on tsunamis, consequences and more
The consequences of these natural events are truly impressive. Faced with the impossibility of alerting with a reasonable time, to carry out the evacuations, they turn it into a silent enemy.
loss of human life
These are very difficult events to predict, since the waves that form gain height as they approach the coast. For this reason, citizens cannot be alerted in time and move to higher and safer regions.
Not only are human lives lost during a tsunami, but thousands of animals and plants are also devastated in the places where these natural events occur.
ruin of real estate
As they are events of great power and speed, they move between all the constructions near the coast and inland. Producing damage of great proportions and sometimes they are disabled for a future occupation
For the reconstruction of the affected areas, large investments in time and economic resources are required. For several months many people are left homeless and have to settle for living in shelters.
As the impact does not distinguish between buildings and hospitals, medical care for the injured is also compromised. This adds one more factor of risk to the crisis caused by the tsunami, since outbreaks of infection are generated.
Imbalance of ecosystems and the environment
Destructive power is another characteristic of a tsunami. It is capable of destroying everything in its path and this includes animals and plants in the areas of occurrence.
Much of the material that it drags with it modifies the relief and ecology of many species. It causes the destruction of entire communities, which would only be able to survive with the environmental conditions prior to the event.
In short, the change is complete and forever, since they are very fragile ecosystems, that it is almost impossible for them to recover on their own and even less with the intervention of the human hand.
damage to the economy
After the disaster, nations and their governments have to invest large amounts of money, which were intended for the productive development of the country. But they have to be reoriented for the reconstruction of the affected areas.
In addition to the disbursement for the reconstruction of the infrastructure, disbursements must be made, for the aid to the affected citizens. For the acquisition of food, equipment and the reconstruction of their homes, if applicable.
Medical emergencies
Not only is it about losing human lives, but the tsunami leaves many injured in its wake and spreads contagious diseases. Many of the pathologies that occur after these devastating events are related to the quality of the water and the state of the food that is consumed.
Overcrowding is another source of disease transmission, many have to stay in shelters, where the demand for space exceeds the capacity to shelter.