304 REPORT — 1889. 



tion best adapted to withstand earthquakes. This committee has already 

 issued several preliminary reports, and vol. xiv. of the 'Trans. Seis. Soc.,' 

 which is now in the press, will give to all who are interested in construc- 

 tion in earthquake countries a detailed account of all the material it has 

 collected which bears upon this subject. 



This material consists of observations made in Japan, Manila, Italy, 

 and many South American countries. In Italy and Manila, at diiferent 

 times, the Government has issued special regulations respecting building 

 in districts which have suffered by earthquakes. 



The following pages may be taken as a summary of these observations 

 and regulations. 



In a paper upon construction in earthquake countries, read before tho 

 Institution of Civil Engineers in 1886,' which was republished with 

 additions by the Seismological Society in 1887, the author suggested 

 several broad principles which ought not to be neglected by those who had 

 to build to withstand earthquakes. The reason that the author was led 

 to make these suggestions was because he had observed that destruction 

 had occurred where, if the builders had considered that the ordinary rules 

 of construction are not altogether applicable when dealing with stresses 

 which are applied more or less horizontally, such destruction might in 

 great measure have been avoided.^ 



The principles suggested were as follows : 



1. To select a site for a building or to give it such foundations that 



it receives the least possible quantity of motion. (In the follow- 

 ing pages, see sections relating to Sites and Foundations.) 



2. To construct in such a manner that buildings may be best able 



to resist stresses due to earthquake motion, these stresses being 

 often applied more or less horizontally. 



In this section the principal subjects which were referred to were un- 

 suitability of archwork to resist horizontally applied stresses, the destruc- 

 tion which has so often arisen in consequence of coupling together parts 

 of a building having different vibrational periods, as, for instance, brick 

 cbimneys and wooden houses, the ill-effects of overloading, &c. In the 

 following pages all these matters are again referred to, but with greater 

 detail, and at the same time much matter which is more or less new 

 has been added. 



1. Choice of a Site. 



A good site may often be obtained in a given city by taking advantage 

 of the results of experience. Thus in the Ansei earthquake in Tokio it 

 was shown that the greatest destruction took place in the low soft ground, 

 while on the high hard ground the destruction was relatively small. 

 Observations of this nature were made in 1883 at Cassamicciola, and these 

 were taken advantage of by the Government when laying out sites for the 

 new town. The occasions when observations like these have been forced 

 upon communities have been very numerous : as for example, at Lisbon 

 in 1755, Port Royal in 1692, Belluno in 1873, in Calabria in 1783, San 

 Francisco in 1868, Talcahuana in 1835, in Messina in 1726. 



Although it is a general rule that the high ground which is hard is 



' Proc. Inst. C. E., vol. Ixxxiii. Session 1885-86, Part I., paper 2108. 

 - ' On Construction in Earthquake Countries,' by John Milne, Trans. Seis. Soc, 

 vol. xii. 



