38o 



NATURE 



{August 1 8, 1887 



been thrown down. This circumstance shows the tenacity of 

 wooden framed structures. Prof. T. Mendenhali, in a report ^ 

 on the recent catastrophe at Charleston, says: — "As was to 

 be expected, buildings constructed of wood suffered much 

 less than those of brick. The interior of wooden buildings, 

 however, would often exhibit a scene of total destruction, 

 furniture, book-cases, &c., having evidently moved with great 

 violence." 



Fire-proof stores, or Kura, suffered severely as to their walls. 

 These buildings have wooden frames, strongly joined by hori- 

 zontal and vertical pieces, and closely covered with laths, the 

 whole making up a compact box-like structure. The roof is 

 tiled, and carefully plastered with a mud which has a slight 

 cementing property, to the thickness of from three to nine 

 inches. This plaster is put on in several layers, each layer being 

 added after the preceding one has dried. The whole process is 

 an expensive one. The walls, on account of their great thick- 

 ness and the poor tenacity of the mud, are easily cracked or 

 stripped. As many as sixty or seventy per cent, of the Kura 

 suffered from the recent shock. It is evident that these thick- 

 walled structures should be replaced by brick buildings, which 

 are equally fire-proof and much stronger. 



It may be mentioned, however, that the frameworks of Ktira, 

 after having been entirely strip])ed, have withstood the most 

 violent earthquake on record. 



In Yokohama, houses are built of different types and with 

 a variety of materi9ls, so that they afford a fair field for 

 the comparison of seismic effects. It is very fortunate that, 

 judging from the effects wrouglit by the recent earthquake on 

 both land and buildings, the seismic intensity in this town was 

 less than one-third of that in the western or hilly parts of the 

 origin-band. But for this, the results would have been highly 

 disastrous. 



The houses which suffered most were the composite structures 

 of wood and stone. They are built of wooden frames encased 

 with stone blocks, each of the latter measuring 2 feet 9 inches 

 long, 9 inches wide, and 6 inches thick, and being clamped to the 

 wooden planks inside by three iron nails. The nail, called 

 Kasugai, is 5 inches long and /^r inch square, and bent at right 

 angles at its two ends. The stone is soft and brittle, being 

 volcanic rock of the worst quality. In time the iron naiU get 

 rusty, and the stones are so acted on by rain and frost as to be 

 easily cracked, or detached from the wooden frames, even by 

 moderate shakings. These buildings, erroneously called Euro- 

 pean houses, already exist in abundance, and unfortunately in- 

 crease each year in number. They are generally constructed 

 with bad materials and on faulty principles ; the object of the 

 builders being to attain fair protection from fire, along with the 

 appearance of a stone building, at the least practicable cost. 



Two brick structures received serious damage, cracks having 

 been formed, as usual, at the corners of the buildings and over 

 the windows. The seismic vibrations, however, left no traces on 

 the Town Hall, the Custom House, Prefectural Office, and other 

 well-built structures of brick or stone. 



In Yokohama, wooden houses sustained no damage worth 

 mentioning. Joints were more or less loosened and tiles occa- 

 sionally fell down from the roofs. The tiles that are fastened to 

 the framework of wooden houses, to form walls, were in some 

 cases detached in large quantities. There are decidedly many 

 improvements which might be made in the present wooden 

 buildings, both of Japanese and so-called European styles, espe- 

 cially in the arrangements of their joints, the scientific distribu- 

 tion of materials, &c. If these and other defects were properly 

 remedied, such dwellings might be made pretty safe as against 

 earthquakes. In sites little liable to danger from fire, one may 

 find, in this country, wooden houses built three and even four 

 centuries ago. Wood, no doubt, will continue for along time to 

 be the chief building material in this country. 



In Japan, however, fire is a more constant and even more 

 dread enemy than earthquakes, while terrible conflagration-; are 

 often brought about by destructive shocks. Hence, brick and 

 stone should, and probably will in time come to be largely em- 

 ployed for building, especially in towns. The question, then, is 

 to select certain types of brick or stone houses which are 

 best calculated to resist earthquake shocks. Sheet and bar iron 

 houses, as used in Australia, would make very efficient earth- 

 quake-proof buildings, although they are not free from several 

 objections. 



After the terrible catastrophe of 1883 in the Island of Ischia, 

 ' The Monthly Weather Review, U.S. Signal Sen-ice, August, 1S86. 



the Italian Government appointed a Commission ^ to consider 

 the reconstruction of the buildings in that island. The Commis- 

 sion, after investigating the different modes of construction most 

 suitable for earthquake countries, submitted models of houses in 

 wood, and in combinations of wood and masonry, which were 

 adopted. The Commission recommended that buildings should 

 be chiefly constructed with an iron or wooden framework, care- 

 fully joined together by diagonal ties, horizontally and vertically, 

 the spaces between the framework being filled in with masonry 

 of a light character. Not more than two stories above ground 

 were to be allowed, &c., &c. 



In Italy, brick houses are joined by iron tie-rods ; and similar 

 devices are now, to a certain extent, used in this country. Con- 

 cerning the erection of brick or stone houses in Japan, much 

 valuable information is to be obtained from the Italians, 

 who, like ourselves, have lived for centuries amidst terrible 

 shakings, and who, no doubt, have gained much experience in 

 the constructive arts suitable to the conditions of our existence 

 here. 



A prominent feature in the effects of the recent earthquake 

 was the overthrowing of brick chimneys in Yokohama, especially 

 on the Bluff. Soon after the shock, circulars were sent round to 

 the principal residents, asking for information as to the effects of 

 the shock on the buildings occupied by them. More than fifty 

 answers were received, and the facts embodied in them have 

 been of great value in preparing this paper. The writer takes 

 this opportunity of expressing his warmest thanks for the kind 

 assistance thus rendered to him. From these answers, from the 

 Police Reports, and from actual observations, fifty-three chimneys 

 appear to have been destroyed. In one instance a heavily-coped 

 chimney fell in a large mass through the roof, and severing a 

 strong beam of i foot by 8 inches on the second story, penetrated 

 to the ground floor. 



About one-half of the chimneys thrown down during the 

 shock were cut in two at their junction with the roof ; while 

 some dislodged the tiling and did sundry other damage to the 

 buildings at their points of contact. Evidently the chimneys 

 and the houses moved with unequal range and with different 

 vibrational periods. Prof. Milne has more than once recom- 

 mended that chimneys should be built thick and squat, 

 without heavy ornamental mouldings or copings ; and be, if 

 possible, disconnected from the roofs. Those houses in which 

 his suggestions had been adopted suffered no damage on 

 January 15. 



Generally, the relations of the seismic effects to the geolo- 

 gical, topographical, and other features of the various localities 

 were found to corroborate previous experience. That the seismic 

 vibrations in hard ground are very much less than in soft soil 

 was well illustrated on the recent occasion. At the University, 

 where the ground is hard and firm, the seismograph recorded 

 only 8 mm. horizontal motion, as compared with 21 mm. regis- 

 tered by a similar instrument placed on soft soil a mile distant. 

 Totsuka is a small town, with a single long street running along 

 the foot of a hill ; one side of the street, however, is built on 

 made-up ground. Most serious damage was done on that side, 

 while the opposite houses suffered very much less, though not 

 more than twenty feet distant. Houses built on cliffs and hill- 

 brows received more damage than those situated at the base or 

 on the flat summits of the same hill. To observe the effects of 

 marginal vibration, the writer recently placed one seismograph 

 at the steep edge of a loamy hill thirty-eight feet in height, 

 and another similar instrument at its foot. The motions, thus 

 far measured, at those two levels are found to be in the ratio 

 of 2 to 1. A third instrument will shortly be set up on the 

 flat summit of the same hill. Observations of a similar nature, 

 on different rocks and at various heights, will form the subject of 

 a further paper. It is probably owing to marginal vibration that 

 houses on the Bluff of Yokohama are always heavy sufferers from 

 earthquakes. 



The extensive and rapidly increasing use of kerosene lamps in 

 Japan constitutes a grave danger in severe shocks. The lamps 

 now in common use are of very brittle materials, contain the 

 most combustible of oils, and are usually poised on ill-balanced 

 stands. In the great earthquake of 1855, at a time when 

 kerosene was unknown in this country, fire broke out in Yedo at 

 more than thirty points, setting a very large part of the city in a 

 blaze. In the event of another such shock, the mischief which 

 would be produced from this cause alone is awful to contem- 



' Proceedings of the Institution of Civil Engineers, vol. Ixxxiii., Session 

 1885-86, part i. 



