Wave propagation in physical models of micromorphic media

Резюме

Рaсnросmрaненuе сеŭсмuческuх волн в мuкроморфноŭ сре¶rt;е, nо mеорuu о¶rt;ноŭ uз возможных мо¶rt;елеŭ сре¶rt;ы в очaге землеmрясенuя, uзучaеmся nуmём ¶rt;вухмерного ульmрaзвукового мо¶rt;елuровaнuя. Полученные резульmamы nокaзывaюm, чmо maкaя сре¶rt;a оmлuчеamся яркоŭ уnругоŭ aнuзоmроnuеŭ u nовыщенным nоглощенuе⇐. Скоросmь рaсnросmрaненuя nрохо¶rt;ящuх nро¶rt;ольных волн nонuжaеmся, uх aмnлumу¶rt;ы резко меняюmся. Преовлa¶rt;aющaя чaсmоma волн, nрохо¶rt;ящuх мuкроморфноŭ сре¶rt;оŭ, nлaвно сmремumся к о¶rt;ноŭ велuчuне, коmорaя связaнa с nросmрaнсmвенным рaсnре¶rt;еленuем, нanрaвленносmью u рaзмерaмu ¶rt;ефекmов, оnре¶rt;еляющuх эmу сре¶rt;у. Полученые резульmamы срaвнuвaюmся с mеорuеŭ мuкроморфноŭ сре¶rt;ы.

Summary

The propagation of seismic waves in a micromorphic body, which is supposed to be one of the possible models of the medium in the earthquake focus, is studied by means of the two-dimensional ultrasonic model technique. The results obtained indicate that such a medium is characterized by distinct elastic anisotropy and by increased attenuation. The propagation velocity of longitudinal waves decreases and their amplitudes change considerably. The prevailing frequency of the waves passing through the micromorphic medium tends smoothly to one value which depends on the space distribution, orientation and dimensions of the elements characterizing such a medium. The obtained results are confronted with the theory of a micromorphic medium.