The shocks then increase in intensity as follows: II. Extremely feeble shocks; III. Very feeble shocks; IV. Feeble shocks; V. Shocks of moderate intensity; VI. Fairly strong shocks; VII. Strong shocks; VIII. Very strong shocks; IX. Extremely strong shocks; X. Shocks of extreme intensity. The meaning of the map presented in the accompanying figure will now become more apparent in several ways. That portion numbered ten, denoting where shocks of greatest intensity have been experienced, clearly indicates the region just above the point where the earthquake originated. Beyond this is a region marked nine where the earthquake shock has decreased in intensity to the next figure on the Rossi-Forel scale, and then to eight and a half, seven, six, five, four, three, and two. [Illustration: FIG. 49. MAP SHOWING REGION AFFECTED BY THE CHARLESTON EARTHQUAKE OF 1886] The Charleston earthquake damaged property to a considerable extent; for, although comparatively few buildings were completely destroyed, a considerable number were partially injured, and many, not thrown down by the shock, had to be torn down in order to insure public safety. The loss of life, fortunately, was comparatively small. During this earthquake a number of openings called _craterlets_ were made in the ground by the forcible ejection of large quantities of water and sand. The empire of Japan is another part of the world particularly subject to great as well as frequent earthquake shocks. Although Japan is also especially noted for its volcanic activity, its earthquakes are almost entirely of the tectonic type, or are due to the slipping of the land at faults in the earth's crust. Most of these quakes occur on the bed of the ocean on the sides of a steep slope that extends down to a very deep part of the Pacific known as the _Tuscarora Deep_. On the 28th of October, 1891, Japan was visited by a great quake, generally known as the Mino-Owaro earthquake, from the name of the two provinces of Mino and Owaro in which it occurred. This earthquake is correctly regarded as one of the most severe in Japanese records. Originating, as it did, in a densely populated section, it caused a great loss of life and property. The deaths reached about 7,000, while the number of houses entirely destroyed reached about 80,000 and those partly destroyed nearly 200,000. The total area markedly affected reached 250,000 square kilometres, while the area sensibly affected reached 900,000 square kilometres, or a little more than one-half the Empire.