Yes, a small shift underwater is the cause of a tsunami.
The Earthquake occurred before the tsunami as it is what caused the tsunami.
Yes.
You can not prevent an earthquake and tsunami like you can prevent getting sick before you get sick.
a tsunami
There was an 8.9 earthquake.
yes there has been
No. A tsunami is a giant ocean wave. A tsunami can be caused by an earthquake, but they are completely different things.
the 9.3 earthquake before it i think
An earthquake happened, which triggered the tsunami.
Generally not. If you are close enough to the source you may feel an earthquake some time before the tsunami, however.
There was a tsunami, but it was triggered by a volcanic eruption, not an earthquake.
Earthquake