www.ccsenet.org/jgg Journal of Geography and Geology Vol. 3, No. 1; September 2011 Published by Canadian Center of Science and Education 171 On the Dependence of Earth’s Seismic Activity on Lunar Distances Muhammad Shahid Qureshi (Corresponding author) Department of Mathematical Sciences, Faculty of Computer Science Institute of Business Administration & Institute of Space & Planetary Astrophysics University of Karachi, C-16, Staff Town, 75270, Pakistan Tel: 92-300-251-2627 E-mail: shahidq@yahoo.com; mqureshi@iba.edu.pk Rashid Ibrahim Institute of Space and Planetary Astrophysics, Karachi University, House # 25, Block D-3, Malir Town Karachi, Pakistan Tel: 92-300-223-8586 E mail: rashid.ispa@gmail.com Received: October 15, 2010 Accepted: November 2, 2010 doi:10.5539/jgg.v3n1p171 Abstract In order to explore any direct link between celestial phenomena and the seismic activity the distance between Moon and the Earth is calculated at the time of all major Earthquakes during the last 109 years. It is found that the Earthquakes (EQ) frequency is very low (4.4%) for lunar distances less than 360,000 km (close to perigee). At large lunar distances greater than 400,000 km (close to apogee), the EQ frequency (27 %) is very high. A cubic relation between the two has a high degree of goodness of fit. This leads to a major revelation that for the period of study there is found a clear dependence of EQ frequency on lunar distances. Keywords: Seismic activity, Lunar distances, Dependence 1. Introduction Earth quake (EQ) is one of the natural disasters on the earth. The main cause that has ever been discovered is energy release during rapid slippage along a fault. Since the middle of the19th century many seismologists and some astronomers have tried to discover the relations between the cause of the energy released and the positions of the moon and the sun in some detail. F. Omori, Rigakushi and Rigakuhakushi (1900) have described the relation between EQ after shocks frequencies with the lunar daily distribution. The occurrence of two maxima in the curves of hourly earthquake distribution at a mean interval of 12 hrs, and approximately at, or little after, the meridian passages of the moon is found to be a common feature. G. P. Tamrazyan (1967) related syzygy zone, phase of the moon and the earthquake frequency. The study revealed that, the earthquake frequency in the new and full moon zones doesn’t always increase; under certain circumstances it shows a substantial decrease. Earthquake frequency during the quadrature moon phase does not decrease; under certain circumstances it increases sharply. Besides the above facts Tamrazyan (1974) presented the evidence to support the hypothesis that the Tashkent earthquake of 1966 April 25 and the largest (intensity V or greater) earthquakes in its aftershock sequence tended to occur under similar 'cosmic' conditions. Tamrazyan (1968) related the two ranges of magnitudes of EQ, an upper magnitudes 8.4–8.9 and a lower magnitude 7.9–8.3 to (a) rotational parameters of the Earth (the so-called V numbers) and (b) lunar declination at culmination. In the last quarter of the century (1940–1964) three-fourths of all earthquake energy was released when the position of the Moon was over the northern hemisphere of the Earth (Tamrazyan, 1969). This positional relationship pertains to the seismic foci of the northern, as well as the southern hemispheres. All the above studies are localized i.e. based on region, period and intensity of EQ, whereas, we have attempted to explore the global EQ data (more than 100 years from May, 1900 to April, 2009), to explore whether there are any links between the celestial phenomena and the seismic activity on the Earth. For this purpose in this work the EQ frequencies are studied in comparison to the lunar distances.