Look Out! Here Comes an Earthquake! Quiz

Answer: principle of inertia

The English professors John Milne, Thomas Gray, and James Ewing are credited with developing the first seismic instruments (seismographs) sensitive enough to be used to study earthquakes. Seismographs use the principle of inertia to study earthquake movement. This law states that an object will stay in uniform motion unless an outside force is applied to it.

Answer: less than 60 kilometers

Earthquakes that are 60 kilometers or less in depth are referred to as shallow. Those that are generated between 60 and 300 kilometers are considered intermediate, and those with a focus greater than 300 kilometers are classified as deep.

Answer: Primary Wave

There are two types of seismic waves. The primary wave has a compressional motion similar to a slinky. The secondary wave has vertical movements. The primary wave moves faster than the secondary wave.

Answer: It destroyed a 2000 year old fort.

On December 26, 2003, a powerful earthquake destroyed much of the city of Bam. Not only did it destroy a 2000 year old fort built primarily of mud brick but the earthquake also killed over 43,000 people. The earthquake was reported to be a magnitude of 6.6.

Answer: Charles Richter

Charles Richter, an American, invented the Richter scale which measures the actual power of an earthquake. The higher the reading, the more powerful and potentially dangerous the earthquake. For example, a reading of 6.0 is 10 times as powerful as a reading of 5.0.

Answer: Japan

England would have been a good guess but it's not the right answer. Although three men from England developed the first seismic instruments, they developed these instruments at an Imperial College in Tokyo, Japan. The first attempts to create seismometers took place in China during the Han dynasty.

Answer: San Andreas Fault

The San Andreas Fault is 1,300 kilometers long and 16 kilometers deep into the earth. San Francisco and Los Angeles are on the Pacific plate while the rest of California and the U.S.A. is on the North American plate. The Pacific plate is moving to the northwest at a rate of around 3 to 4 inches per year.

Answer: epicenter

The first motion of an earthquake within the earth is called the focus. The hypocenter is the location of the focus. The epicenter is directly above the hypocenter.

Answer: Chile

The largest was the Chilean earthquake in 1960 which measured an unsurpassed 9.5 on the Richter scale.

Answer: mainshock

The smaller earthquake that occurs before the largest earthquake is called a foreshock. The largest earthquake that happens in the same place is called the mainshock. Then, the series of earthquakes that follow the main earthquake are called aftershocks.