What kind of wave released during an earthquake

Although useful for decades, this technique has been replaced by digital calculations. Seismic stations record ten earthquakes in this animation.

People have always tried to quantify the size of and damage done by earthquakes. Since early in the 20th century, there have been three methods The oldest of the scales is called the Mercalli Intensity scale. Earthquakes are described in terms of what nearby residents felt and the damage that was done to nearby structures. Today these maps are still important and various seismological stations will create shake maps of the surface damage.

With the invention of the seismograph station, the Richter magnitude scale was created. Developed in by Charles Richter, this scale uses a seismometer to measure the magnitude of the largest jolt of energy released by an earthquake. Today, the moment magnitude scale has replaced the Richter scale. The moment magnitude scale measures the total energy released by an earthquake.

Moment magnitude is calculated from the area of the fault that is ruptured and the distance the ground moved along the fault. The Richter scale and the moment magnitude scale are logarithmic.

The amplitude of the largest wave increases ten times from one integer to the next. An increase in one integer means that thirty times more energy was released. The sound energy travels through the ground, but it can also be transmitted into the air. Students mark the coils so that they can see the movement of energy along their length. Have two students each hold one end of the slinky for their group.

Stretch out the slinky to about 3 meters along a floor, table, or other flat surface. Have students take turns compressing 10—20 coils and then releasing them rapidly while they hold the end of the slinky, making sure to watch the energy wave travel the length of the slinky.

After several repetitions, ask students to describe their observations of the coil and the tape: the coils move back and forth along the length of the slinky as they compress and expand it.

Ask students what kind of earthquake waves this slinky motion resembles. The answer is compressional waves. Remind them that in compressional waves particles of material move back and forth parallel to the direction in which the wave itself moves. As a compressional wave passes, the material first compresses and then expands. P-waves P stands for primary are compressional earthquake waves that pass through the interior of the Earth.

P-waves change the volume of the material through which they propagate. Note: P-waves in the air are sounds. P-waves can move faster through the ground than the air, but not all of this energy is in the range of human hearing. When the sound waves are in the audible frequency range, some people may hear them. Now tie one end of a 2-meter rope to the door knob of the classroom door. Ask the student to back away from the door until the rope is straight with a little bit of slack and start to gently shake the rope up and down.

Allow each student to create this motion. After several repetitions, ask students to describe the rope motion. Ask them what kind of earthquake wave motion this resembles. The answer is shear waves. Remind them that in shear waves particles of material move back and forth perpendicular to the direction in which the wave itself moves. S-waves S stands for secondary are shear earthquake waves that pass through the interior of the Earth.

S-waves don't change the volume of the material through which they propagate, they shear it. Note: The motion of the rope due to shear waves is much easier to observe than the compression waves, but the shear waves travel more slowly than compression waves. In an earthquake, scientists can observe the arrival of compression waves before the arrival of shear waves using seismographs.

You may choose to show a close-up of a record seismogram for a single earthquake event, and ask your students to point out different seismic waves.

In addition, shear waves cause much more damage to structures since it is easier to shake surface rocks than it is to compress them. Encourage your students to critically evaluate their slinky and rope setup. Download 0 items. Twitter Pinterest Facebook Instagram. Email Us. See our newsletters here. Would you like to take a short survey? This survey will open in a new tab and you can fill it out after your visit to the site.

Yes No. Some of those vibrations will move forward and back through the material they travel through. Other waves travel just like ocean waves, where they make the material they pass through move up and down compared to the direction the wave is traveling.

And while some of these waves travel deep within the planet, still others move only along the surface. Studying where these various flavors of waves are and how they move not only can help scientists pinpoint where an earthquake or explosion occurred, but also can shed light on the structure of our inner planet.

Seismic waves are vibrations in the ground. These can be generated by a number of phenomena, including earthquakes, underground explosions, landslides or collapsing tunnels inside a mine.

There are four major types of seismic waves, and each typically travels at different rates of speed. If the waves arrived at vibration-detecting instruments — seismometers Sighs-MAH-meh-turz — all at the same time, it would be difficult to tell them apart. Another major difference between these types of waves is how a material will move as the wave passes through it.

Seismologists are scientists who study earthquakes. The fastest seismic waves are known as P waves. And early seismologists called them that because these waves were the first to arrive at seismometers from some distant quake.

Deeper within the planet, where pressures are higher and material is typically more dense, these waves can travel up to 13 kilometers per second 8. P waves travel through rock the same way that sound waves do through air. That is, they move as pressure waves.

When a pressure wave passes a certain point, the material it is passing through moves forward, then back, along the same path that the wave is traveling. P waves can travel through solids, liquids and gases. In general, S waves are only 60 percent as fast as p waves.