The prediction about a huge earthquake that is about to occur in California is giving me something to think about. Why? Because California is where I live. There has been much talk as to how we should prepare for this walloping event which has been predicted to occur very soon!!!!!
When I heard the recent news about New York having an earthquake, I was in shock because New York City, with all its tall buildings, is not known to have earth quakes. In fact, when the citizens of this city felt the huge rumblings, they thought it must be due to another terrorist attack. Because of all this news, I became curious. I wanted to know what causes earthquakes. I also felt this would be an important lesson for students.
Scientists believe that pressures in the earth’s crust causes earthquakes. When there is a weak point in the earth’s crust, the crust breaks and moves. This is what causes the quake. The break in the earth’s crust is called a fault. Lately, this is what we have been hearing about in the news. California is known to have a fault.
When there is a slight movement of the ground, it is referred to as a tremor. It has been reported that there are over six million tremors a year in the earth’s crust. Sometimes these tremors are so slight that they cannot be felt. The only way we know that there has been a tremor is because an instrument, known as a seismograph, has been developed that measure these movements.
As you probably know, earthquakes can cause a lot of damage. On March 27, 1964, the ground in Anchorage, Alaska shook with such great force that 115 people had died. Buildings had fallen apart. There were great cracks in some of them. There were also cracks in some of the streets.
In 1835, a scientist explored the Andes mountains, which is located in South America. He found the remains of sea animals and plants that lived a long time ago. He discovered the remains of trees that usually grow near the sea. He knew that sea animals grow near the sea and not on mountains.
This scientist believed that this land was once covered by the sea. He thought to himself that long ago, these mountains may have been part of the ocean floor. Pressure inside the earth (the earthquake) caused this land to rise above the ocean.
In 1935, a man by the name of Charles Richter developed a scale for determining the strength of an earthquake. His scale was based on the size of the wavy lines on what is known as a seismogram. If the lines are large, this means that the earthquake was strong. Small ones meant that the earthquake was weak.
The Richter Scale gives each earthquake a score from 1 to 9 or more. The higher the number, the stronger the quake. An earthquake scoring of 6 or higher can cause a lot of damage. Of course, the stronger the structure of a building, the less damage there is. This is why it is important for cities to have strong buildings.
Source: A Lesson for Students, “How Does the Earth Crust Move?”