A tsunami is a massive sea wave caused by earthquakes, volcanic eruptions, underwater landslides, and meteor impacts. Natural warning signs are often monitored and observed to prevent this sea wave. One of the signs is a felt shaking of the ground. If you are in a tsunami-prone area while the ground is shaking, protect yourself first by doing the Drop, Cover, and Hold On. Immediately go to higher ground when the shaking stops. Another sign is sea recession which is the receding of the water exposing the normally submerged areas. If this is observed, immediately run away from the shore. And the last sign to look for is hearing an unusual noise similar to that of a train or jet aircraft. Do not wait for an official warning if one of the natural signs of an impending tsunami is observed.