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Why is a large earthquake followed by numerous aftershocks?

Why is a large earthquake followed by numerous aftershocks?

Aftershocks. Aftershocks are earthquakes that usually occur near the mainshock. The stress on the mainshock’s fault changes during the mainshock and most of the aftershocks occur on the same fault. Sometimes the change in stress is great enough to trigger aftershocks on nearby faults as well.

What do multiple aftershocks mean?

Aftershocks are earthquakes that follow the largest shock of an earthquake sequence. They are smaller than the mainshock and within 1-2 rupture lengths distance from the mainshock. In general, the larger the mainshock, the larger and more numerous the aftershocks, and the longer they will continue. …

Which is bigger an earthquake or an aftershock?

Most large earthquakes are followed by additional earthquakes, called aftershocks, which make up an aftershock sequence. While most aftershocks are smaller than the mainshock, they can still be damaging or deadly. A small fraction of earthquakes are followed by a larger earthquake, in which case the first earthquake is referred to as a foreshock.

What happens to the Earth after an earthquake?

Earthquakes can cause a lot more damage after the first shock. They are often followed by aftershocks, causing even more damage to already weakened buildings and roads. Land, especially hills, can also be damaged by earthquakes and result in devastating landslides and mudslides. What is an aftershock?

The magnitude of an earthquake is related to the length of the fault on which it occurs. That is, the longer the fault, the larger the earthquake. A fault is a break in the rocks that make up the Earth’s crust, along which rocks on either side have moved past each other.

Effect of aftershocks. An aftershock sequence is deemed to have ended when the rate of seismicity drops back to a background level; i.e., no further decay in the number of events with time can be detected.