Hi EQ Forecasting. To test the hypothesis, earthquake data for 600 earthquakes occurring in North America in 1986 was gathered. This information was available from Dr Zhou, a geophysicist at the University of Houston Department of Geosciences. The form at of the data was then converted from days and months to days of the year, 1-365. Using a 1986 calendar indicating the phases of the moon, each day of the year was given a tidal range from 0-7, with 7 being the high tides (new and full moon), and 0 being neap tides (1st and 3rd quarter moons).

The number of days in the year for each type of tidal day (0 through 7) was counted. Then number of earthquakes occurring on each type of tidal day was determined. Finally, the average number of earthquakes per day (or earthquake frequency) for days o f different tidal magnitudes was calculated by dividing the number of earthquakes per tidal magnitude by the number of days per tidal magnitude.

Using Cricket Graph III, a Macintosh program, these data were plotted on a graph . Then a linear regression analysis was done to determine if there is a linear relationship between earthquake frequency and tidal magnitude. A correlation coefficient (r squared value) indicates how closely the points fall on a straight line.

This plot shows that, in general, earthquake frequency increases with increasing tidal magnitude. During neap tides, slightly more than 1.5 earthquakes per day occurred; during spring tides, more than 1.8 earthquakes per day occurred. The linear regression line, determined by the computer, has a very high correlation coefficient, showing a strong linear correlation. Given the number of data points, the r2 value or 0.898 is statistically significant to the 1% level (Snedecor and Cochran, 1965), thus there is less than a 1 in 100 chance that these two variables are not related.

In conclusion, the researcher found that there is a small but statistically significant increase in the frequency of earthquakes during periods of high tides. This study supports the idea that tidal triggering of earthquakes occurs, thus the hypothesis was correct. The increase in earthquakes is very slight, however, so you don't have to worry about an earthquake with every full or new moon! Take Care…Don in creepy town

• Tidal Triggering