Can an aftershock of an earthquake have a higher magnitude than the earthquake itself?

Answer 1

The short answer is no. If in greater magnitude, probably is a new earthquake.

Aftershocks are earthquakes in the same region of the central shock (generally within a few rupture length) but of smaller magnitude and which occur with a pattern that follows Omori's law. Omori's law, or more correctly the modified Omori's law, is an empirical relation for the temporal decay of aftershock rates. Omori published his work on the aftershocks of earthquakes, in which he stated that aftershock frequency decreases by roughly the reciprocal of time after the main shock, in 1894.

An earthquake storm is a recently proposed theory about earthquakes, where one triggers a series of other large earthquakes—within the same tectonic plate—as the stress transfers along the fault. This is similar to the idea of aftershocks, with the exception that they take place years apart. These series of earthquakes can devastate entire countries or geographical regions. Possible events may have occurred during the end of the Bronze Age, and the latter part of the Roman Empire. It has been suggested that this is what may be occurring in modern day Turkey.[1]

The term was coined by Stanford Professor of Geophysics Amos Nur in 2000.[

Remotely triggered earthquakes have also been characterized as 'The very long reach of very large earthquakes' [1]. Fundamentally, it is postulated that large earthquakes can have an influence outside of the immediate aftershock zone, and actually activate other earthquakes at considerable distance [2]. The further one gets from the initiating earthquake in both space and time, the more controversial is the association.

The physics involved in actually triggering an earthquake is complex. Most earthquake-generating zones are in a state of being close to failure. If such a zone were to be left completely alone, it would generate significant earthquakes spontaneously. Remote earthquakes, however, are in a position to disturb this critical state, either by shifting the stresses statically, or by dynamic change caused by passing seismic waves.

OK, I know, probably way more than you cared to know.

Answer 2

The aftershock of an earthquake is usually lower in magnitude than the earthquake itself!

Answer 3

It differs depending upon the accumulated stress and the finish of tectonic plate boundaries. I am doing research right from my house from the past 6 years. I have some imported and my own designed simple instruments to sense the earthquake waves. I am the one issued the warning 2 hours before Tsunami struck our Indian coast. Mostly we get the report of minor quakes after heavy one. But on 24th July 2005@ 15.30 Indian STD time I was sensing minor wave for a long period. The same day after 6 hours major earthquake of 7.1 struck at Andaman Island. This was also alerted by my instrument. Some parts of our city Chennai in India only observed small shaking. But we have not felt any physical shaking in our area. This incident itself is the proof for the capability of my quake alarm. But the seismologists are not showing real interest to make use of my inventions. Most of the times we get only small quakes after big one. Therefore we can not say which way it will affect.

Answer 4

Earthquakes consist of earth tremors (shaking) and the epicenter at the surface and often deep below can be pinpointed by seismic recorders. Tremors may proceed and follow an earthquake. The earthquake relieves built up stress within the earth often at slip planes (existing faults). Although unlikely, a large earthquake could follow a small earthquake in a certain area although the epicenter may have shifted. Relieving stress in one location can increase stress in another (to the breaking point!).

Answer 5

I live in Christchurch. It was very very scary...but I'm afriad it won't be fixed by next week. We are still getting scary aftershocks...that will apparently last for weeks to come. The damage will take months to clear.