Abstract
Magnitude obtains its physical basis when it is converted to energy by a simple relation. Radiated energy is considered as the energy of earthquake. This energy is a function of the focal depth, the moment of a double couple force system and the time process at the source. Depth dependency of the energy is expressed by
1/ρ(1/VP5+1.5/VS5)
and is determined when a certain earth model is given. Such depenency, or the correction in energy determination, is calculated. The dip and slip angles and the direction of the strike do not affect the energy, but they give important effect to the amplitude of the wave from which the magnitude is calculated. Supposing that the energy and magnitude show one-to-one correspondence, the magnitude correction for the dip and slip angles and the direction of the strike as well as for the focal depth was introduced. By this correction, the magnitude obtains its physical meaning and expresses the moment of earthquakes. The two kinds of corrections mentioned above were obtained by using the theoretical seismograms of surface waves with poriods of 17-18 sec.
