# planetwater

ground- water, geo- statistics, environmental- engineering, earth- science

## Some Effects on Water and Statistics From the Recent Earthquake in Japan

This is a blog about water and statistics. Admittedly, in a very broad sense. Neither earthquakes nor related problems with nuclear power stations are at first glance directly related to these two topics. However, the earthquake was so strong that its consequences are felt widely. Even in groundwater wells in which the seismic waves from an earthquake induce water level fluctuations. This phenomenon has been pointed out both by the NGWA blog and by Dave Campagna at WaterWired

Image from WaterWired

If this earthquake has been felt by groundwater wells, it was really big. But how big? As theusrus.de points out, only one earthquake of the USGS data-set he used that contains all earthquakes since 1973, has been bigger.

The “size” of an earthquake is measured on the logarithmic Richter scale, which is used as the x-axis in the above histogram. The recent earthquake in Japan was linked with a value of 9.0 on the Richter scale. The earthquake in the Indian Ocean around christmas 2004 was the one that was bigger since the recent one in Japan, with a value of 9.3 on the Richter scale. The folks at Mathematica seem to have a little larger time series, which contains one more earthquake of magnitude bigger than 9.0 — it happened in 1964 in Alaska, USA. It’s always fun to look at something logarithmic on a linear scale:

The folks at Mathematica also have a nice map of where earthquakes happen, and great info on seismic waves and plate tectonics.

And finally, two visualizations of descriptive statistics:

–  xkcd has posted a nice graphic visualizing radiation dose units: what activity leads to which radiation exposure and how big is that dose compared to other activities

– IBM has produced a nice graphic showing the deaths per TWh by energy sources (nuclear energy is not the worst in that measure).

Written by Claus

March 26th, 2011 at 8:33 am

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