Talk:Aftershock

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When can an aftershock be considered a new earthquake? Fox news is reporting the March 28/29th quake in Indonesia as an aftershock of the December 26th quake in 2004. I would think that after three months a new tremor in the same area would no longer be considered an aftershock.

Aftershocks can continue for many years after a large earthquake. However, the magnitude of the aftershocks drops quickly with time. I don't think it's clear as of this writing whether the March 28/29 quake is an aftershock or a new main shock. It is certainly related to the December quake, though. Gwimpey 03:31, Mar 29, 2005 (UTC)

I think this really comes down to a definition of aftershock. I put "earthquake aftershock" into Google and the best definition contained two criteria namely "in the same area" and "is usually a magnitude smaller". I updated the article to include "in the same region" in the definition. The earthquake mentioned above does not meet either criterion. It was not in the same real estate being 150 km southeast of the 2004 earthquake and its aftershock region and in the range of 2-4 times smaller based on the final magnitude of the 2004 earthquake being 9.0 or 9.3. This Caltech article mentions the earthquake or aftershook issue but doesn't give a definitive answer.

i addressed some of the above in my additions but it must be remembered that the idea of what an aftershock is is defined by its fit to an emperical relation (Omori's law). some poeple think that aftershock actualy follow an exponential decay, based of a model and that the n(t) can be fit just as well (with no data at very small or large times you can really tell they apart). others suggest almost all events are aftershocks and that a finite (but small) chance exists that any event will be followed by another that is larger than itself so a forshock is really just a large aftershock. Bumfluff 20:56, 7 September 2005 (UTC)