Flood, tornado, earthquake, drought, tsunami volcano 1. a sudden shaking of the earth's surface, which may cause great damage; 2. a very violent wind in the form of a tall wide pipe of air that spins at a great speed; 3. a very high, quickly travelling sea wave caused by an undersea earthquake or similar disturbance; 4. a mountain with a crater at the top, through which lava, steam gases, etc. sometimes escape with explosive force; 5. an overflow of water; a large amount of water covering a place that is usually dry; 6. a long period of time when there is no rain and crops die.