The earthquake — tremors and vibrations of the Earth's surface caused by natural reasons or artificial processes (explosions, filling reservoirs, underground cavities collapse of mine workings). Small tremors can be caused also the rise of the lava during volcanic eruptions.
Every year on Earth there are about a million earthquakes, but most of them are so minor that they go unnoticed. Really strong earthquake that can cause extensive damage to occur on the planet about once in two weeks. Most of them are on the bottom of the oceans, and therefore is not accompanied by catastrophic consequences.
Earthquakes are most known for the devastation they can produce. The destruction of buildings and structures caused by fluctuations in soil or giant tidal waves (tsunamis) that arise when seismic shifts on the seabed.
Most of the foci of earthquakes occurs near the Earth's surface.
Earthquakes can also be caused by landslides and large landslides. Such earthquakes are called sharp, they have a local character and a small force.
1. Letters were being sent at 5 yesterday.
2. A new play for the theatre is written every year.
3. Next week the whole class will be taken to the museum.
4. Her car is being washed now.
5. The article was being read.