What is intensity of an earthquake

Therefore, the Richter scale has been replaced by the moment magnitude scale, symbolized as M w. The moment magnitude scale is broadly similar to the Richter scale, but it takes more factors into account, including the total area of the fault that moves during the earthquake, and how much it moves.

This produces a magnitude number that is a better indicator of the total amount of energy released by the earthquake. Because the moment magnitude scale has replaced the Richter scale, we will assume from here on that we are referring to moment magnitude, not Richter magnitude, when we speak of earthquake magnitude.

The magnitude scale portrays energy logarithmically to approximately base For example, a magnitude 6. A magnitude 7. A magnitude 9. Earthquake intensity is very different from earthquake magnitude. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place. Therefore, each earthquake produces a range of intensity values, ranging from highest in the epicenter area to zero at a distance from the epicenter. The most commonly used earthquake intensity scale is the Modified Mercalli earthquake intensity scale.

The table below shows approximately how many earthquakes occur each year in each magnitude range and what the intensity might be at the epicenter for each magnitude range. The following table gives intensities that are typically observed at locations near the epicenter of earthquakes of different magnitudes. Answer the question s below to see how well you understand the topics covered in the previous section.

This short quiz does not count toward your grade in the class, and you can retake it an unlimited number of times. Use this quiz to check your understanding and decide whether to 1 study the previous section further or 2 move on to the next section.

Privacy Policy. Heavy objects and furniture overturn or topple. Big church bells may ring. Old or poorly-built structures suffer considerable damage. Some well-built structures are slightly damaged. Some cracks may appear on dikes, fish ponds, road surface, or concrete hollow block walls. Limited liquefaction, lateral spreading and landslides are observed.

Trees are shaken strongly. Liquefaction is a process by which loose saturated sand lose strength during an earthquake and behave like liquid. People find it difficult to stand even outdoors. Many well-built buildings are considerably damaged. Concrete dikes and foundation of bridges are destroyed by ground settling or toppling.

Railway tracks are bent or broken. Tombstones may be displaced, twisted or overturned. Utility posts, towers and monuments mat tilt or topple. Water and sewer pipes may be bent, twisted or broken. Liquefaction and lateral spreading cause man- made structure to sink, tilt or topple. Numerous landslides and rockfalls occur in mountainous and hilly areas.

Boulders are thrown out from their positions particularly near the epicenter. Fissures and faults rapture may be observed. Trees are violently shaken. Water splash or stop over dikes or banks of rivers. IX Devastating People are forcibly thrown to ground. Many cry and shake with fear. Most buildings are totally damaged. Numerous utility posts, towers and monument are tilted, toppled or broken.

Water sewer pipes are bent, twisted or broken. Landslides and liquefaction with lateral spreadings and sandboils are widespread.

Trees are shaken very violently with some toppled or broken. Boulders are commonly thrown out. River water splashes violently on slops over dikes and banks. How long does an earthquake last? Why are aftershocks recorded? What is the difference between Magnitude and Intensity? What is the Modified Mercalli Intensity Scale?

What is the Richter Magnitude Scale? Does the direction of rupture influence the size of the impact in different places? Does the Earth really ring like a bell after a big earthquake? Earthquake Hazards.

Earthquake - What to do? Lesson Plans. Virtual Tours.