The Most Common Cause of Tsunamis: Understanding More About Tsunamis

In 2018, Indonesia’s tsunami early warning system failed to detect a tsunami near the Anak Krakatau Volcano. This failure occurred because the trigger of this catastrophe is not the most common cause of tsunamis. 

On the other hand, Indonesia’s tsunami EWS could only detect tsunamis that are triggered by the most common incident. This country programmed its tsunami EWS that way because this cause generates about 80% of tsunamis in the world. 

What is the Most Common Cause of Tsunamis?

Tsunami waves are different from tidal waves. These waves occur because of powerful seafloor movements. These movements are highly associated with violent plate tectonic movements that trigger earthquakes. Therefore, it is no wonder that earthquakes are the leading cause of tsunamis. 

• How do Earthquakes Generate Tsunamis? 

An earthquake can make the seafloor abruptly deform. This deformation will result in the displacement of a massive volume of seawater. Consequently, a series of huge waves will travel quickly in all directions. Those waves eventually hit coastal areas.

The waves typically need less than an hour to touch the shorelines if the epicenter of the earthquake causing the tsunami is not far from the shores. However, those waves may hit those areas hours to days after the quake if the epicenter is far away.

The height and speed of tsunami waves vary depending on the magnitude of the earthquake. Some waves are extremely tall and move exceptionally fast. Consequently, they can destroy houses and infrastructure along the coastal areas.

Moreover, tsunamis can sweep away people on the shorelines and drown them. The inundation of sea water and tsunami debris may also contaminate the soil and drinking water and damage crops.

• Not All Earthquake Can Cause Tsunamis

Are earthquakes the most common cause of tsunamis? Yes, but not all earthquakes can trigger tsunamis. Earthquakes can trigger tsunamis if it has an epicenter in a subduction zone under an ocean. 

Moreover, they must be shallow earthquakes with a depth of less than 70 km under the ocean floor. In addition, earthquakes can generate tsunamis if their magnitudes are over 6.5 SR. Earthquakes with a magnitude of 8 SR or above typically can cause destructive tsunamis. 

Other Causes of Tsunamis

Tsunamis can occur because of natural phenomena other than earthquakes. What are these causes?

1. Landslides

Subaerial and submarine landslides can cause tsunamis if earthen materials flow into an ocean and displace a vast amount of seawater. Tsunamis generated from landslides can destroy coastal areas nearby. 

However, those deathly waves typically lose energy quickly. Therefore, it is rare for the tsunamis to reach distant areas. In most cases, landslides can cause tsunamis if they are generated by powerful phenomena, such as strong earthquakes and volcanic eruptions.

2. Volcanic Eruptions

Submarine and subaerial volcanoes can generate tsunamis when they explode. During an eruption, volcanoes emit an excessive amount of lava and other volcanic materials. When they flow into the ocean, an immense volume of seawater may be displaced.

Consequently, a series of strong waves will hit nearby areas. Volcanogenic tsunamis are rare. Some well-known volcanogenic tsunamis are those triggered by the Santorini eruption in 1600 BC and by the Krakatoa eruption in 1883.

Another destructive volcanogenic tsunami in modern times is the Sunda Strait Tsunami. In December 2018, Indonesia suffered from this type of tsunami. 

Before the deathly waves hit the coastal areas along the Sunda Strait, Anak Krakatau Volcano erupted. This eruption caused parts of the volcano to fall into the Sunda Strait. This tsunami killed more than 400 people and injured over 13,000 people.

More About Tsunamis

When people get a tsunami warning or read about tsunami news, they often associate this catastrophe with a destructive disaster. However, not all tsunamis are damaging. They vary in speed and height. Below are some characteristics of tsunamis.

• Inundated Areas: The most common tsunami areas are low coastal regions. The inundated area of tsunamis can be a few meters inland. However, the inundation can reach 3 km inland in low-lying areas if the tsunamis are gigantic.

• Tsunami Height: Most tsunamis are only a couple of meters in height. Nonetheless, tsunami height increases when the wave passes shallow coastal waters. Moreover, some tsunamis can reach 50m tall in areas closer to the epicenter if the earthquake is of 9 magnitude or over.

• Tsunami Speed: The tsunami can cross the ocean at a maximum speed of 800 km per hour. However, it will decrease to 50 km/h or less when reaching the shore.

The most common cause of tsunamis is earthquakes. However, tsunami EWSs must be programmed to detect tsunamis generated from other causes to minimize victims. Moreover, governments must equip those EWSs with cell broadcast machines. Visit smsbroadcaster.com now to get these machines.