which country has the most earthquakes

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Request for Question Clarification by tutuzdad-ga on 11 Apr 2006 08:08 PDT

It is difficult, if not impossible, to narrow the answer down to one
specific country since earthquakes in one region are often felt in
another region. Add to this the fact that earthquake epicenters are
often not within the official bountries of any given country yet their
most damage is occassionally recorded in one. Let me know if this
answers your question as well as possible under the circumstances:

"Which countries have the largest and most frequent earthquakes?
 
Around 75% of the world's seismic energy is released at the edge of
the Pacific, where the thinner Pacific plate is forced beneath thicker
continental crust along 'subduction zones'. This 40,000 km band of
seismicity stretches up the west coasts of South and Central America
and from the Northern USA to Alaska, the Aleutians, Japan, China, the
Philippines, Indonesia and Australasia.

Around 15% of the total seismic energy is released where the Eurasian
and African plates are colliding, forming a band of seismicity which
stretches from Burma, westwards to the Himalayas to the Caucasus and
the Mediterranean."
EARTHQUAKE QUESTIONS AND ANSWERS 
http://www.moorlandschool.co.uk/earth/images/Earthquakefaq.htm#FAQ03
 
tutuzdad-ga

The following link lists the largest earthquakes in the world since
1900 (magnitude 8.5 and higher).

http://earthquake.usgs.gov/regional/world/10_largest_world.php

The list includes 12 earthquakes.  Of those earthquakes, 7 of the
largest 12 earthquakes, and three of the largest four, occured in just
a fifteen year period from 1950 to 1965.

This site says that Japan has the most earthquakes:
http://www.insite-tokyo.com/column/joanne/index11.html


This one, however, suggests that Iceland may be in the running,
especially considering that the country is so small:
http://hraun.vedur.is/ja/englishweb/index.html

Here is a really interesting website:
http://tsunami.geo.ed.ac.uk/local-bin/quakes/mapscript/home.pl#

Of course, there are earthquakes and earthquakes.  The last one I
experienced only rattled my dropleaf table, I didn't feel anything.

Thinking about numbers of earthquakes, whilst interesting, is not what
scientists generally do as earthquake size varies massively. What
seismologists and geologists actually use is Seismic Moment, a measure
of the energy released in an earthquake.  A better measure of the
country which experiences the most earthquakes would be to look at
which experiences the highest total seismic moment, summed over all
earthquakes.

In areas where very large earthquakes occur, such as Sumatra or the
Himalayas, the total seismic moment is dominated by very large and
rare earthquakes.  Earthquakes like the one off Sumatra occur only
every few thousand years or so.  Given that worldwide seismic
monitoring has only been going a few decades it is unlikely we have a
full idea of how common and how widely spread such large earthquakes
are.  Hence a certain answer to your question is rather difficult to
ascertain.