Evening Republican, Volume 21, Number 155, Rensselaer, Jasper County, 11 July 1918 — Various Earthquake Sounds. [ARTICLE]

Various Earthquake Sounds.

Earthquake sounds are described as variations of heavy rumbling, so low in pitch as almost to be more felt than heard (in many cases inaudible to persons who are deaf to very low tones), and belonging to one or another of the following types: The passing of wagons, thunder, wind, the fall of a load of stones, the fall of a heavy body, an explosion, or some other miscellaneous sound. In strong earthquakes the sound area occupies a central region (on an average two-thirds) of the disturbed region; 1 in moderate earthquakes the two areas are approximately of the same magnitude; while in many slight earthquakes the sound area is larger than the disturbed area. As a rule the beginning of the sound precedes the shock, and the end of the sound follows the end of thr shock.