GEOLOGY

Detailed explanation-1: -Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a larger event or “mainshock.” They occur within 1-2 fault lengths away and during the period of time before the background seismicity level has resumed.

Detailed explanation-2: -What is an aftershock? When a relatively large earthquake occurs, a series of smaller earthquakes will follow continuously around the epicenter of the first earthquake. We call this first large earthquake “mainshock” and the subsequent “aftershocks”.

Detailed explanation-3: -In seismology, the mainshock is the largest earthquake in a sequence, sometimes preceded by one or more foreshocks, and almost always followed by many aftershocks.

Detailed explanation-4: -Foreshocks come before large earthquakes, in the same location. Sometimes a foreshock may be identified incorrectly as the mainshock until a larger one occurs after it. Neither foreshocks nor aftershocks can be bigger than the mainshock.

Detailed explanation-5: -Large earthquakes are often followed by aftershocks, the result of changes in the surrounding crust brought about by the initial shock. Aftershocks are most common immediately after the main quake. As time passes and the fault recovers, they become increasingly rare.