55 



This indicates either an extreme velocity of movement or great depth of dis- 

 turbance, probably both. The large area affected and the comparative mildness 

 of the shock at the epicentrnm indicate that the disturbance was deep. A disturb- 

 ance at a small depth might be felt over a large area, but if so, the force at the 

 epicentrum would be great. According to the conclusions of Capt. Dutton from 

 his studies of the Charleston (S. C.) earthquake,* the wave movement at that 

 time had a velocity of about three miles per second. At this rate, it would re- 

 rjuire 1.38 minutes for a wave to travel from Charleston, Missouri, to Indianapolis. 

 It will be seen that it would have required close observation to determine the 

 difference in time at which the wave was felt at Evansville and at Indianapolis. 

 The average time of the shock as reported from Charleston, Cairo, and Columbus 

 was 5 o'clock 8 minutes and 20 seconds, or 2 minutes and 10 seconds earlier than 

 the average time reported from Indiana. 



An interesting feature of this earthquake is the fact that its epicentrum has 

 approximately the same position as that of the earthquake of 1811 which resulted 

 in the sinking of large areas about the mouth of the Ohio River for a distance of 

 several feet. 



There are newspaper reports of an earthquake at Cotapaxi, Colorado, No- 

 vember 18 at 4:10 p.m. ; one at Greeley, Colorado, November 24th at 5 a. m. ; and 

 one at Clayton, Delaware, November 20, at 3 A. M. There was an earthquake of 

 some severity reported from Rome and Naples, Italy, November 1. Wlien we 

 consider the great frequency of earthquakes in volcanic regions and in regions 

 where there is great orustal disturbance, these closely simultaneous earthquakes 

 in distant parts appear as probable coincidences hardly worthy of remark. It is 

 reportedt that in .lapan there is an average of at least one earthquake a day. 

 According to the records kept at Lick Observatory^ there was an average of one 

 earthquake for every 11.4 days in the State of California for the years 1800 and 

 1891. 



* Ninth An. Rep. U. S. Geolog. Survey. 

 t Rep. Brit. Association, 1884, p. 242. 

 i Bull. U. S. Geolog. Survey, No. 79. 



