Tokyo Magnitude 8.0 reach her own daughter and mother in Sangenjaya. Together, the three of them brave the partly ruined city and try their best to make it home safely. The series was first announced at the 2009 Tokyo Anime Fair, denoting that it would replace "Eden of the East" in Fuji TV's noitamina well-rated anime timeblock and would be co-produced by Bones and Kinema Citrus. The series' setting is based upon the prediction that there is 70% or higher chance of an earthquake measuring 7.0 magnitude on the Richter scale hitting Tokyo in the next 30 years, with the series illustrating the
Moment magnitude scale band. To simplify this calculation, he noted that the lowest frequency parts of the spectrum can often be used to estimate the rest of the spectrum. The lowest frequency asymptote of a seismic spectrum is characterized by the seismic moment, . Using an approximate relation between radiated energy and seismic moment (which assumes stress drop is complete and ignores fracture energy), (where E is in Joules and is in Nformula_4m), Kanamori approximated by The formula above made it much easier to estimate the energy-based magnitude , but it changed the fundamental nature of the scale into a moment magnitude scale.