May 6, 2012 – Earthquakes and Tsunamis by Longitude: The graph above reflects global earthquakes and tsunamis by east and west longitude. The data was downloaded from NOAA. Both the earthquake and tsunami databases were through May 5, 2012. The earthquake data started in 2150 B.C. and included 4,162 years, for magnitude 7 or higher, with 1,457 events. The tsunami data started in 1410 B.C. and included 3,422 years, with 813 events.
The earth is divided by longitude and latitude lines, so that any location on the globe may be exactly marked, as shown below:
The zero (0*) Longitude line runs vertically through Greenwich, England (just east of London). From 0* to -180* is west longitude, while 0* to +180* is east longitude. Zero (0*) latitude marks earth’s equator, with 0* to +90 marking north latitude and 0* to -90* showing south latitude. Both longitude and latitude are measured in degrees, minutes and seconds. There are 60 minutes in one degree and 60 seconds in one minute.
Clearly, there are more quakes in east longitude (965 – 66%) versus the west (492 – 34%). The download with 1,457 events did not lend itself to computation by country, so I used the 354 event download to prepared a graph of the top 20 countries, in terms of earthquakes:
The east has the most quakes because the countries with the most earthquakes are located in the east, e.g., Indonesia, Japan, Russia, etc. (see graph). The 21 quakes shown for the USA were mostly in Alaska or the Aleutian Island chain (12), California (7), Idaho (1) and Hawaii (1).
So far, 2012 has seen six quakes greater than 7.0 magnitude. Three of those were off the west coast of Northern Sumatra (Indonesia), one in the Vanuatu Islands, one in Mexico and one in Chile. The last two on the list occurred on April 11, 2012 and where 8.6 and 8.2 events that were only two hours and five minutes apart (both off the west coast of Northern Sumatra).
The map below shows the locations of those two quakes (8.6M and 8.2M) in relation to the 9.1 mega-quake and tsunami of December 26, 2012:
Similarly, the majority of the Tsunamis were in east longitude, with 595 in the east (73%) and 218 in the west (27%). Below, is a graph of the top 20 countries, in terms of tsunamis:
Japan had 250 and Indonesia 57, which are both in east longitude. One reason Japan shows so many tsunamis is that they tended to keep better records than other countries, and the country is prone to tsunamis generated primarily from earthquakes.
Of the 56 USA tsunamis, the oldest is the January 26, 1700 Cascadia Subduction Zone event; which took place off the northwest coast of the U.S. The newest on the list took place on September 2, 2011; at the Fox Islands, Aleutian Islands, Alaska. It is interesting to note that of these 56 tsunamis, seven were greater than 100 feet high. The highest of any tsunami reported over the 3,422 year period is the July 10, 1958 southeast Alaska event; which was an incredible 1,722 feet high (see my post on this event). Further, of the 56 U.S. tsunamis; seven had tsunamis greater than 100 feet, with the oldest listed first: 394’, 200’, 110’, 490’, 115’, 1,722’ and 220’ (all in Alaska). Lastly, the 1,722 foot July 1958 tsunami was cause by a landslide, rather than an earthquake or volcanic eruption.
The Master of Disaster