EARTHQUAKE MOTION DEDUCED FEOM OBSERVATION. 91 



Another set of interesting results are those of 

 P. Serpieri on the earthquake of March 12, 1873. The 

 curious manner in which this shock radiated is described 

 in the chapter on the Geographical Distribution of Earth- 

 (juakes (seep. 231). Two large areas appear to have been 

 almost simultaneously struck, so that, there being no time 

 for elastic yielding, the velocities calculated between places 

 situated on either of the areas are exceedingly great. ^ 



From Ragusa to Venice the velocity was 2,734 feet per second 

 „ Spoleto „ „ 4,101 „ „ 



„ Perugia to Orvieto „ 601 „- „ 



„ „ „ Ancona „ 1,640 „ „ 



- '•^''^ " (orvsl •• 



The following are examples of approximate earth- 

 quake velocities which have been determined in Japan. 



The Tokio Earthquake of October 25, 1881. — From re- 

 cords respecting this earthquake it appears to have been 

 felt over the whole of Yezo and the northern and eastern 

 coast of Nipon, a little farther south than Tokio. It was 

 severest at Nemuro and Hakodate, and at the former place 

 a little damage was done. From these facts, together 

 with the indications of instruments recording direction of 

 movement and a general inspection of the time records, 

 it seems that the disturbance must have originated beneath 

 the sea on the east coast of Yezo at a very long distance 

 to the north-east of Tokio, from which place it passed in 

 a practically direct line on to Yokohama. 



As the disturbance was felt at Yokohama twenty-one 

 seconds later than at Tokio, and the distances between 

 these two places is about sixteen geographical miles, for 

 this portion of its course the disturbance must have 

 travelled at a rate of at least 4,300 feet jper second. If 



* See remarks on the Earthquake ' Push,' p. 162. 



