550 



SCIENCE. 



[N. S. Vol. XXIV. No. 618. 



festation of action as it presents itself to us 

 in time need by no means represent the 

 actual time-period which marked the be- 

 ginning or end of a disturbance, whether 

 volcanic or seismic. 



If we once assume, and as the facts seem 

 to indicate justly, that an interrelation be- 

 tween volcanic and seismic distuibances may 

 be extended over a region of 2,000 miles or 

 more, naturally it becomes impossible to 

 state to what further limits this relation- 

 ship may not extend; in other words, how 

 far removed may a volcano be from an 

 earthquake to be brought into correspond- 

 ence with it. This question can not now be 

 answered, but it is certainly a significant 

 fact that a very large number of the greater 

 earthquakes have been at (or about) times 

 when there have been violent or paroxysmal 

 eruptions, however distantly removed the 

 points of such eruption may have been. 

 And it can also be stated that extreme vol- 

 canic activity in one part of the globe is 

 frequently synchronized, or shortly fol- 

 lowed, by similar activity elsewhere. This, 

 in a measure, and perhaps equally so, holds 

 true of earthquake disturbances. These 

 conditions, taken in connection with the 

 facts that have been earlier recited in this 

 paper, it seems to me, tend to prove that 

 a causal bond unites the two classes of phe- 

 nomena, and that they have a common 

 origin in some internal planetary stress or 

 convulsion. 



It has been claimed by those who sharply 

 distinguish between volcanic and tectonic 

 earthquakes that the earth movement, 

 whether in force or in lateral extent, that 

 distinguishes the former is small compared 

 with that of the latter, but the facts that 

 have already been brought forward render 

 the accuracy of this conclusion extremely 

 doubtful.^^ Indeed, the geologist, in the 



"The breaking into activity of Klutchevskaya, 

 the lofty volcano of Kamtchatka, on. October 6, 

 1737, seems to have been, the occasion of an 



face of the far-reaching mechanical work of 

 evisceration which so largely distinguishes 

 many eruptions, would on a priori grounds 

 be justified in hesitating before he an- 

 nounced this conclusion, and he could ask 

 himself the much-neglected question: what 

 must be the result of the removal in a short 

 period of so much material from the earth's 

 interior? The volcano of Askja, in Ice- 

 land, as a result of its eruption on January 

 4, 1875, is estimated to have thrown out 

 from the rifts of the Myvatus Oraefi lava 

 which in quantity measured 31,000,000,000 

 cubic feet, or the equivalent of a block 20 

 miles long, 5 miles wide and 100 feet thick.^^ 

 The discharge from Skaptar JokuU, in 

 1783, was calculated, as we have already 

 seen, to have equaled a block 6.2 miles 

 long, 3.1 miles broad and 1,771 feet thick; 

 that from Bandai-San, Japan, in 1888, 1.2 

 cubic kilometers; from Krakatao, in 1883, 

 4.3 cubic miles ( !) ; and from Temboro, on 

 Sumbawa, in 1815 (as estimated by Ver- 

 beck), 28.6 cubic miles. The geologist is in 

 the habit of looking complacently upon the 

 removal of this vast material from the 

 earth's interior, but is it at all likely to 

 have been accomplished without prodigious 

 jarring of the earth's crust somewhere? 

 It is only when we begin to properly appre- 

 ciate the vastness of this evisceration that 

 we are prepared to receive, apart from 

 other evidence, the probability of far-reach- 

 ing action in the eruption of a volcano. 

 Even the minor quantity of material 



earthquake which agitated nearly the whole of the 

 Kamtchatkan peninsula and a large part of the 

 region of the Kuril Islands. The earthquake 

 which in 1861 annihilated the town of Mendoza, 

 in Argentina, costing the lives of probably not 

 less than 10,000 inhabitants, was coincident with 

 the opening of the volcano of Mendoza near by; 

 the earthquake of Arequipa, Peru, in 1868, was 

 coincident with the opening of one side of the 

 volcano of Arequipa (MistI). 



"W. G. Locke, 'Askja,' 1881, p. 26. 



