ENERGY INPUT RATE IN EARTHQUAKE DESTRUCTIVENESS : Comparison between epicentral and oceanic earthquakes

Abstract

The Hyogoken-Nanbu Earthquake of January 17, 1995 was characterized by its very large acceleration amplitude discharged in a very short duration. Such an epicentral earthquake motion having a high rate of energy input exhibits severer destructiveness for structures than an ordinary oceanic earthquake motion characterized by slow accumulation of energy input. Large energy input in a period shorter than the oscillator's natural period tends to knock down the oscillator in a monotonic manner before the oscillator exhibits its ample capacity of energy absorption in the hysteresis loops. Therefore, the structures susceptible to an epicentral earthquake needs more strength to survive such a pulse-like excitation.