In what conditions can an earthquake form a tsunami?

Question

In what conditions can an earthquake form a tsunami?

Answer 1

If there is a shift of tectonic plates in the ocean and they conversion upon each other creating massive vibrations making waves

Answer 2

The most common cause is a seafloor earthquake. Other triggers are undersea landslides, undersea volcanic eruptions, and meteorite impact. Sudden changes to the seafloor cause the ocean to flow away from the disturbance, creating waves.

Answer 3

I thing I am the right person to answer this question because I have issued the warning 2 hours before Tsunami struck our coast and I have also issued denial report on several other occasions even though our seismologists issued false warnings. I am not just joking. I have records for my claims. Here is the conditions.The magnitude must be not less than 7 in Richter scale, not only the epicenter the force also should have been released in the sea. One of the tectonic plate should have moved up or down this is called compressional type of movement of tectonic plates.Some times the epicenter may be in an island and the force released in sea and some times vise versa. The depth should be fairly less.Some times the earthquake confuses our seismologist why because for instant the earthquake affected Indonesia Padang was the peculiar case. The epicenter was in the sea.But the force was released in island.Therefore it has not created Tsunami. On this incident after knowing a complete car show room was destroyed I issued the denial report.This time was also our local police continued to vacate the people from sea shore.

Answer 4

If an earthquake occurs on the seafloor it requires a particular motion to cause a tsunami. There must be some amount of strike-slip offset. That means one part of the earth is thrust upwards in relation to the other. This results in a sudden movement of the water column above the fault generating a tsunami. The size of the wave is dependent upon the throw and length of the offset. For example, the Indian Ocean tsunami from a few years ago resulted from fault movement of over 10 meters along many kilometers of fault.

Another earthquake generated tsunami can result from undersea ground slumping. A quake near a deep sea valley or canyon could trigger a large piece of earth to slide. This has the same effect as fault offset. The earth moves and disturbs the water column above, generating the wave.

The size and strength of a tsunami is relative to the amount of earth movement and the depth at which it occurs. If it's in the deep ocean (~4km) then the resulting wave is 4km high. But, if the offset is small, the force of the wave will be as well.