236 HOVEY— EARTHQUAKES : [April 24, 



compare with the volcanic outbursts of Krakatoa, 1883, destroying 

 36,500 victims; Vesuvius, 1663 (18,000) ; Mt. Pele, 1902 (29,000) 

 and the Soufriere of St. Vincent, 1902 (1,400), other historic 

 eruptions having entailed comparatively small loss of life. 



Although earthquakes have been recorded frequently throughout 

 all historic time, seismology is one of the youngest of the sciences 

 — it is still in its formative state. Scientific interest in the subject 

 has indeed not been lacking, but real edvance was retarded by the 

 fact that, up to the latter part of the nineteenth century, the causes 

 of the phenomena were sought without rather than within the earth 

 itself. Geology was not seriously called upon for aid in solving 

 the problems. 



The modern science of seismology is generally held to have had 

 its beginning with the publication, in 1862, of Robert Mallet's great 

 book upon the so-called Neapolitan, or better Basilicata, earth- 

 quake of 1857. Mallet, however, approached his task with the pre- 

 conceived idea that earthquakes were always caused by subterranean 

 explosions, and his observations and deductions were warped ac- 

 cordinigly. The science received its real start from Eduard Suess, 

 when he published in 1874^ his brilliant generalization showing the 

 intimate association of more than forty Austrian earthquakes with 

 the already well-known Kamp, Thermen and Miirz fault lines near 

 Vienna and postulated crustal movements as an important cause of 

 seismic disturbances, thus combatting the "centrum" theory of 

 Mallet and others. Suess followed this paper with a still more im- 

 portant paper- the next year along the same lines showing the inti- 

 mate relation of the great earthquakes of southern Italy and Sicily 

 to the fault zones of the region. Impetus was added by the publi- 

 cation of the illuminating treatise of Rudolph Hoernes^^ in 1878, in 

 which earthquakes were first definitely classified into ( i ) those due 

 to the collapse of the roofs of cavities within the earth's crust, (2) 

 those resulting from explosions connected with volcanic eruptions 

 and (3) tectonic quakes, or those caused by crustal movements 

 along fault planes or due to other effects of the action of mountain- 



^"Die Erdbeben Nieder-Oesterreichs," Denkschr. k. Akad. Wiss., Wien, 

 XXXIIL, Abth. I., p. 61, 1874. 



= " Die Erdbeben des siidlichen Italien," id., XXXIV., Abth. I., p. i, 1875. 

 ^Jahrbuch d. k. k. Geol. Reichsanstalt, XXVIII., p. 387, Wien, 1878. 



