Investigation of earthquake mechanisms and their impact on certain basic
concepts in earthquake engineering and seismology
Men Fulu
Institute of Engineering Mechanics, China Seismological Bureau, Harbin, China
Abstract: In this paper, mantle circulation flow, continental drift,
earthquake origin and other mechanical principles are examined as they apply to
earthquake engineering, seismology and dynamics of fluid saturated porous
medium. The relationship of mantle flow to earthquakes is examined and
clarified, and a new model, different from Haskell’s, is proposed for the
earthquake mechanism. The proposed new model is based on the discovery that two
pairs of jump stress and jump velocity will start to act from the fault plane.
Records obtained directly from recent earthquakes nearby and right on the fault
break show a very large velocity impulse, which verify, indirectly, the new
mechanism proposed by the author. Further, at least two physical parameters that
characterize the seismic intensity must be specified, because according to the
discontinuous (jump) wave theory, at the earthquake source, the stress jump and
the velocity jump of particle motion should act simultaneously when a sudden
break occurs. The third key parameter is shown to be the break (fracture)
propagation speed together with the break plane area. This parameter influences
the form of the unloading time function at the source. The maximum seismic
stress in and displacement of a building are estimated for two unfavorable
combinations of the building and its base ground in terms of their relative
rigidity. Finally, it is shown that Biot’s theory of wave propagation in fluid
saturated porous media is valid only when fluid flow cannot occur.
Keywords: mantle circulation flow; plate motion; earthquake mechanism;
wave propagation; break (fracture) propagation; unloading wave; jump wave;
building; Biot’s theory
