Table of Contents
What is the power of an earthquake?
It causes the surface of the earth to shake. To describe the strength of quakes, scientists use a scale of numbers called the Richter scale. The Richter scale grows by powers of 10. An increase of 1 point means the strength of a quake is 10 time greater than the level before it.
What measures the intensity of an earthquake?
The Richter scale measures the largest wiggle (amplitude) on the recording, but other magnitude scales measure different parts of the earthquake. Intensity is a measure of the shaking and damage caused by the earthquake; this value changes from location to location.
How are earthquakes recorded?
Earthquakes are recorded by instruments called seismographs. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. Instead the spring or string that it is hanging from absorbs all the movement.
Is hypocenter and focus the same?
The hypocenter is the point within the earth where an earthquake rupture starts. Also commonly termed the focus.
What is considered a big earthquake?
Getty/AFP A strong earthquake is one that registers between 6 and 6.0 on the Richter scale. There are about 100 of these around the world every year and they usually cause some damage. In populated areas, the damage may be severe. A magnitude 6.5 quake struck southeastern Iran Dec.
How many times stronger is a 6.0 earthquake than a 4.0 earthquake?
Therefore, an earthquake of magnitude 6 has thousand times more destructive energy than an earthquake of magnitude 4.
What is the highest intensity of earthquake?
Science Center Objects
| Mag | Alternative Name | |
|---|---|---|
| 1. | 9.5 | Valdivia Earthquake |
| 2. | 9.2 | 1964 Great Alaska Earthquake, Prince William Sound Earthquake, Good Friday Earthquake |
| 3. | 9.1 | Sumatra-Andaman Islands Earthquake, 2004 Sumatra Earthquake and Tsunami, Indian Ocean Earthquake |
| 4. | 9.1 | Tohoku Earthquake |
What four factors affect the intensity of an earthquake?
When an earthquake strikes, the intensity of earthquake shaking determines the severity of damage. In turn, the main factors affecting earthquake shaking intensity are earthquake depth, proximity to the fault, the underlying soil, and building characteristics—particularly height.
What is the atomic bomb equivalent to a 8.0 earthquake?
Seismic energy by magnitude compared:
| Magnitude | Energy in joules (J) | TNT equiv. |
|---|---|---|
| 5.0 | 2.0 x 1012 | 500 tons of TNT |
| 6.0 | 6.3 x 1013 | 15 kilotons of TNT |
| 7.0 | 2.0 x 1015 | 500 kilotons of TNT |
| 8.0 | 6.3 x 1016 | 15 million tons of TNT |
Can earthquakes be predicted?
While part of the scientific community hold that, taking into account non-seismic precursors and given enough resources to study them extensively, prediction might be possible, most scientists are pessimistic and some maintain that earthquake prediction is inherently impossible.
Where do earthquakes show the most damage?
The epicenter is the point on the land surface that is directly above the focus. In about 75% of earthquakes, the focus is in the top 10 to 15 kilometers (6 to 9 miles) of the crust. Shallow earthquakes cause the most damage because the focus is near where people live.
What does the P stand for in P wave?
primary
Compressional waves are also called P-Waves, (P stands for “primary”) because they are always the first to arrive.
Earthquakes and Seismic Waves When an earthquake occurs, rocks at a fault line slip or break, and two sections of Earth’s crust physically move relative to one another. That movement releases energy, and two types of seismic waves radiate outward from the earthquake through Earth’s interior and along its surface.
How does a seismogram help you find an earthquake?
Seismograms come in handy for locating earthquakes too, and being able to see the P wave and the S wave is important. You learned how P & S waves each shake the ground in different ways as they travel through it. P waves are also faster than S waves, and this fact is what allows us to tell where an earthquake was.
Which is the primary preliminary wave after an earthquake?
The P wave is designated the primary preliminary wave because it is the first to arrive at a seismic station after an earthquake. It travels at a speed usually less than 6 kilometers per second in the Earth’s crust and jumps to 13 kilometers per second through the core. The S wave is the secondary preliminary wave to be recorded.
How is the speed of a seismic wave determined?
The speed at which seismic waves travel depends on the properties of the material that they are passing through. For example, the denser a material is, the faster a seismic wave travels (SF Table 7.1).