Archive for ‘Uncategorized’



An apology again.
Apart from the Lists and the Timeline Charts this Blog is pretty well redundant now that Google maps has been changed to Google My Maps.
As I mentioned in February, Google will no longer show the KMZ/KML files these maps are created from.
I have begun the arduous task of transferring my research to Bing Maps, using ikiMaps to create the interactive maps and i-frames.
There is also an issue with WordPress. WordPress only recognizes Google i-frames, therefore both Google Maps and WordPress are not fit for my purposes on this project any longer.
Please refer to my new Blog, World Significant Earthquakes 314-2014 on Blogger.



Sorry folks, the maps are almost redundant (end of Feb 2015) due to Google changing their policy on Google Maps being able to read KMZ data (which is how these maps are created). You will already notice that the “view larger map” has already disappeared from below each map. I am looking at alternative formats.



1977 and 1978 have been updated, 1977 +4 and 1978 +3 newly found events from the Centennial List.
Graphs have been updated
* Note. If you are following the updates on a regular basis, you may have to clear your cookies to be able to see the new updated charts and maps rather than the old ones. I had problems seeing them myself until I realised what was going on.


All Mag 8 + Quakes 314-2014

text list, opens in new window

Based on data from the International Institute of Seismology and Earthquake Engineering, Building Research Institute’s version of Utsu’s research Catalog of Damaging Earthquakes in the World (Through 2001) PC Edition and the USGS Centennial List 1900-2002, cross referenced with NOAA, NEIC, Geofon and EMSC


Project Graphs

The graph below shows the number of 7+ quakes each decade.
Certainly looks like an increase in numbers since the 1990’s.
Major World Earthquakes 1900-2010 Graph

The following graph shows the number of 7+ events 1910-2011 on a yearly basis.
With another decade added it looks that the 1930’s, 1950’s and 1980’s were quieter compared to the other 4 decades.
Major World Earthquakes 1910-2010 Graph

These graphs will change as I complete more years going back.


Project Progress

It has been brought to my attention that most of the data pre 2000 is incomplete.

ER Engdahl and A Villasenor from the University of Colorado, Boulder, USA have published a comprehensive publication “Global Seismicity: 1900-1999” which brings together many secondary catalogues such as Gutenberg & Richter’s 1954 publication “Seismicity of the Earth”, which provides most of the larger earthquakes occuring between 1904 and 1952.
Other catalogues such as Abe (1981, 1984), Abe and Noguchi (1983), Bath and Duda (1979), Geller and Kanamori (1977), Pacheco and Sykes (1992) and Rothe (1969) are used in compiling the data.

I have run the data within the “Centennial Catalog” for two years, 1949 & 1950 beside the data I have already used and found another 17 and 21 respectively.
Therefore I will revise each year again, as time permits, until all data is complete, before moving on to pre 1910.
As the data is entered and published I will mark the bars on the charts with an red tip to show those that have been revised
* Note. If you are following the updates on a regular basis, you may have to clear your cookies to be able to see the new updated charts and maps rather than the old ones. I had problems seeing them myself until I realised what was going on.


1935 Introduction of the Richter Scale

Charles Francis Richter and Beno Gutenberg, seismologists at the California Institute of Technology (Caltech), Pasedena, Clifornia developed a standard scale to measure the relative sizes of earthquake sources, called the Richter scale

At the time when Richter began a collaboration with Gutenberg, the only way to rate shocks was a scale developed in 1902 by the Italian priest and geologist Giuseppe Mercalli. The Mercalli scale classified earthquakes from 1 to 12, depending on how buildings and people responded to the tremor. A shock that set chandeliers swinging might rate as a 1 or 2 on this scale, while one that destroyed huge buildings and created panic in a crowded city might count as a 10. The obvious problem with the Mercalli scale was that it relied on subjective measures of how well a building had been constructed and how used to these sorts of crises the population was. The Mercalli scale also made it difficult to rate earthquakes that happened in remote, sparsely populated areas.

The scale developed by Richter and Gutenberg (which became known by Richter’s name only) was instead an absolute measure of an earthquake’s intensity. Richter used a seismograph – an instrument generally consisting of a constantly unwinding roll of paper, anchored to a fixed place, and a pendulum or magnet suspended with a marking device above the roll – to record actual earth motion during an earthquake. The scale takes into account the instrument’s distance from the epicenter, or the point on the ground that is directly above the earthquake’s origin. Richter chose to use the term “magnitude” to describe an earthquake’s strength because of his early interest in astronomy; stargazers use the word to describe the brightness of stars. Gutenberg suggested that the scale be logarithmic, so that a quake of magnitude 7 would be ten times stronger than a 6, a hundred times stronger than a 5, and a thousand times stronger than a 4.

The Richter scale was published in 1935 and immediately became the standard measure of earthquake intensity. Richter did not seem concerned that Gutenberg’s name was not included at first; but in later years, after Gutenberg was already dead, Richter began to insist that his colleague be recognized for expanding the scale to apply to earthquakes all over the globe, not just in southern California. Since 1935, several other magnitude scales have been developed. Depending on what data is available, different ones are used, but all are popularly known by Richter scale.
– Source – Wikipedia