JAPANESE EARTHQUAKES — HECK 213 



trialized, but various types of structures having a design, borrowed 

 from other countries, which ignored earthquakes, were destroyed. 

 The region is primarily agricultural, one of the most important rice- 

 raising districts of Japan, and in spite of its few cities the population 

 density was second only to the Tokyo-Yokohama region, being 778 

 per square mile. The intensity is evidenced by the loss of 140,000 

 nouses, only a few of which were destroyed by fire. Along some of the 

 highways every house was down. (PI. 3, fig. 1.) 



The area of greatest destruction covered 4,300 square miles. The 

 rice culture required many roadways and ditches and there was heavy 

 damage to them and to embankments. A number of bridges suffered, 

 some spans being thrown off the piers. An area of three-fourths of a 

 square mile subsided so that a river mouth was blocked and the land 

 became swampy. In one place the faulting resulted in complete de- 

 struction of a village, a half acre of land being turned over so that 

 nothing remained but clods and upturned roots. At another place two 

 persimmon trees in a garden were shifted, without damage, so that the 

 direction between them changed from east-west to north-south. Build- 

 ings were damaged as far away as Osaka. There were great land- 

 slides in the mountain region to the north. The number of after- 

 shocks at Gifu in 2 years was 3,365, of which 10 were violent and 97 

 were strong. From these data Omori derived his well-known curve 

 of decline of frequency of aftershocks. From fallen stone lanterns 

 he estimated the maximum acceleration at 0.4 g. Earthquakes have 

 been few in this region since the aftershocks ceased. Since the 

 epicenter was distant from the sea, this was one of the very few great 

 Japanese earthquakes that was unaccompanied by a tsunami. 



The Japanese Government centered at Kyoto from 794 to 1868. 

 The records kept make it certain that Kyoto and its port, Osaka, have 

 had no great earthquakes in their vicinity. From 1480 to 1820 the 

 most important were in 1596 (No. 2 in table 1), and in 1854, south of 

 Lake Biwa. A destructive earthquake in 1899 at Osaka is mentioned 

 by Davison. It should be said here that yet other destructive earth- 

 quakes are obviously expected by the Japanese, since the imperial 

 palace at Kyoto, where the emperors are crowned, was strengthened in 

 recent years. A prominent Japanese seismologist expressed such a 

 view to the writer at Osaka in 1926. The damage at Osaka due to 

 earthquakes in region II must not be overlooked. 



The Tazima, 1925, and Tango, 1927, earthquakes strictly belong to 

 region V, but they are remote from others in that region and are near 

 the rest of region IV, and the Tango earthquake bears some resemblance 

 to the shock of 1891. The Tazima earthquake originating in Tuiyama 

 Cove on the coast of the Japan Sea was destructive, damaging 7,500 

 houses and causing more than 400 deaths, but its chief interest lies in 



