Earthquakes and Volcanoes
The Earth’s crust is made up of very large rocks called plates. Sometimes the plates move and rub against each other. This movement may cause the earth to shake, sometimes slightly and sometime violently. A sudden violent shaking as a result of the movement of the plates is called an Earthquake.
When the movement is very slight we call it an Earth Tremor.
Sometimes after a violent shaking we may have a slighter movement occurring and we call this movement an After Shock.
Earthquakes are caused from the faults (cracks) in the earth’s crust. These faults are deep inside the earth’s surface where the rocks move and break from time to time. The point in the earth where the earthquake begins is called the Focus.
Directly above the Focus on the surface of the earth is the Epicenter of the Earthquake. The most damage from an earthquake occurs at the epicenter.
Earthquake waves are called seismic waves. The higher the waves the stronger the earthquake.
The strength of the earthquake is measured by a Richter Scale.
Earthquakes are given a number from 1 – 10. The higher the number, the stronger the earthquake. An earthquake measuring 6 or 7 on the Richter scale is considered to be very violent and could cause severe damage including loss of life.
Most earthquakes occur along or near the edges of plate boundaries.
In the Caribbean Sea, severe earthquakes have caused serious damage.
In 1692 an Earthquake measuring 6 on the Richter scale destroyed Port Royal and several persons lost their lives.
In 2010 an earthquake measuring 7 on the Richter scale destroyed Port-au-Prince, Haiti and killed several people.
Ring of Fire – Considered to be the most active earthquake zone and is located in the pacific ocean. Many plate bounderies meet and there are numerous fault lines in this region.
Other Disaster cause by an Earthquuake.
Earthquakes cam trigger other disasters such as fires from ruptured gas lines, fallen power lines, flooding from broken water mains and reservoirs and all Tsunamis.
A tsunami is usually caused from an Earthquake or Volcano occurring in the ocean floor. A part of the ocean floor may move which causes huges waves to travel to the shores and can travel very far into the land. The waves are very powerful and pulls back to the ocean anything in its path on land.
A volcano is an opening in the earth’s surface. Beneath the earth is the innermost layer also called the core where hot molten magma exists. When magma reaches to the surface it tis called lava. When the lava cools and hardens it builds a mountain which is called a volcano.
The opening of the volcano is called a vent.
A volcano may be active, dormant or extinct.
Ring of Fire – Area in the Pacific Ocean with the most active earthquakes and volcanoes.