THE PHILIPPINE 



Journal of Science 



A. Chemical and Geological Sciences 

 and the Industries 



VOL. VIII AUGUST, 1913 No. 4 



THE RELATION OF SEISMIC DISTURBANCES IN THE PHILIP- 

 PINES TO THE GEOLOGIC STRUCTURE 



By Miguel Saderra Mas6 j and Warren D. Smith 



(From the Weather Bureau, and the Division of Mines, Bureau of Science, 



Manila, P. I.) 



Three maps 



In the light of studies of the last ten years, stimulated by the 

 tremendous cataclysms of Messina and San Francisco, entirely 

 new principles have been introduced into the study of seismic 

 disturbances of the crust of the earth. The old centrum theory 

 of Mallet is generally discredited. 



Beyond a doubt, many seismic disturbances are due to causes 

 other than vulcanism. Many of the worst disasters we have 

 experienced have nothing to do with volcanoes, and that volca- 

 noes are nearby is only a coincidence, or may be explained by the 

 fact that the place where great disturbances in the earth's crust 

 occur is naturally a zone of weakness and where molten material 

 would be expected to seek an outlet. At the time of the Messina 

 earthquakes, Mount Etna, which can be seen from Messina, was 

 comparatively quiet. The great disturbance at Messina, as is 

 generally known, was due to an adjustment along the line of a 



1 Assistant Director of the Weather Bureau. 

 U8S66 199 



