Reply #26: or maybe we can... [View All]

[Viva_La_Revolution]

When it comes to detection rates for major earthquakes over 100 years ago, it is worth noting that our ability to record all earthquakes of 7.0 or above occurring across the planet prior to 1901 is uncertain, and so there is likely to be some incomplete data in the 19th century, because of this. It was only in 1897 that a global network of seismographs was deployed. The numbers shown for the period from 1863 to 1900 may therefore be lower than actual, although it is unlikely to be more than three or four times that shown. (records for major 'quakes were fairly good from the 1880s onwards). It is acknowledged that care and good judgement must be exercised in using global seismic data, as there may still be incomplete data from our sources even after 1901. This report has been based on data available from USGS (NEIC) and other online sources, such as Wikipedia, in an attempt to cover as much of the available data as possible .


DATES FROM & TO PERIOD NO. EARTHQUAKES (Mag. > 6.99)
--------------------------- -----------
1863 to 1900 incl 38 yrs 12
1901 to 1938 incl 38 yrs 53
1939 to 1976 incl 38 yrs 71
1977 to 2014 incl * 38 yrs 164 (to Mar. 2011) predict >190 in total.

* Although periods are shown up to 2014, this report was initially written in 2006. Therefore the final period (from 1977) will be updated as required until the end of 2014. In the meantime a predicted total is shown.
The earthquake (OFF EAST COAST OF HONSHU, JAPAN) - incidently one of the largest in recent decades - on 11th March 2011 is the last included in these numbers.

Apart from the "long-term" trends shown above, which show an ongoing persistent increase, it is perhaps more stark to record that earthquakes across the planet show a marked increase in activity since 1997. There are more major earthquakes occurring now, and this on an ever more frequent basis.

http://www.earth.webecs.co.uk/