TEE LATEST CALABRIAN DISASTER 139 



A sixth object of study should be the tsunamis or "tidal waves" 

 which apparently followed upon the recent shocks, since it has been 

 demonstrated that such waves go out from the deeps of the sea appar- 

 ently as the result of movements upon the floors of those deeps. That 

 these movements are not directly connected with the land disturbances 

 is apparent in their absolute lack of relation to such disturbances, even 

 when the land disturbance is localized at and near the border of the 

 sea. The California earthquake of 1906 was followed by no afterwave, 

 though the Yakutat Bay (Alaska) eartliquake of 1899 was succeeded by 

 an inundating wave over forty feet in height. 



Great deeps of the Mediterranean occur both to the north of Sicily 

 (the Tyrrhenean deep on the site of a former land area) and also 

 to the southeastward in the Ionian depression. Fortunately the land 

 areas form a barrier between these deeps and furnish unusual oppor- 

 tunities of localizing the sea floor movements on the basis of the shore 

 lines which have been washed by the wave. A series of soundings in 

 these deeps, which have been already surveyed with considerable care, 

 should afford a confirmative determination, provided changes not ascrib- 

 able to errors in either series of soundings should be discovered. Such 

 a discovery would certainly take foremost rank among earthquake 

 investigations. 



To sum up, therefore, it may be said that the proposed scientifie 

 expedition should be prepared to carry out at least six separate lines of 

 investigation, since conditions are in all cases unusually favorable for- 

 study. These lines are : ( 1 ) a re-survey by soundings of the sea bottom- 

 separating Sicily from Calabria; (2) the preparation of precise and 

 accurate maps by expert topographers of all sections of the land which 

 have suffered noteworthy visible deformation; (3) the re-occupation of 

 primary triangulation stations in the vicinity of the straits of Messina, 

 in order to determine changes in location and elevation; (4) the dis- 

 tribution of the damage on the land with due regard to the depth andl 

 character of superficial deposits, and further comparison of the results; 

 with those of earlier quakes within the same district; (5) a magnetic re- 

 survey of the near shores (unless this is to be carried out by Italian 

 workers) ; (6) the taking of a sufficient number of soundings over the 

 great Tyrrhenian and Ionian deeps to determine whether changes in. 

 depth explain the after-waves of the earthquake. 



As precedent for such studies conducted upon foreign soil, it 

 should be stated that the great Andulusian earthquake of Christmas 

 Day, 1884, was studied by a French Commission headed by Professor 

 F. Fouque, sent out by the Paris Academy of Sciences. The same 

 disaster was also successfully investigated by an Italian Commission 

 sent by the Royal Academy at Rome, and our present knowledge of 

 this earthquake is very largely based upon the monographs which were 



