390 SEISMOLOGY. 



SEISMOLOGY. 



[For previous reports see Year Book No. 20, pages 175 to 178.] 



REPORT OF THE ADVISORY COMMITTEE. 



In 1921 the Advisory Committee in Seismology recommended to the 

 President and Trustees of the Carnegie Institution of Washington that the 

 Institution enter the field of Seismologic Research, taking up at the outset 

 the pressing problem offered by the West Coast region of the United States, 

 where earth movements in considerable variety occur and so little is known 

 about them that they constitute a tangible menace to large engineering and 

 other development enterprises and sometimes to human hfe. It was pointed 

 out that appropriate instruments for the study of such local earth movements 

 have not been developed hitherto and are very much needed. Furthermore, 

 as research is organized in the United States, no other institution is in posi- 

 tion to take up such a task single-handed because of the number of different 

 considerations involved in attacking the problem satisfactorily. It was there- 

 fore recommended that the Institution invite the participation of a number of 

 agencies, through the cooperation of which an adequately comprehensive 

 attack might be inaugurated and competent conclusions assured. 



In particular it was recommended that the Ukiah and Lick Observatories 

 be invited to continue and extend their observations of latitude for the pur- 

 pose of establishing (or disproving) a northward crustal creep or drift which 

 had been indicated by earlier observations; that the U. S. Coast and Geodetic 

 Survey be invited to extend its system of primary triangulation and precise 

 levels until no considerable area within the various zones of movement in 

 California can suffer displacement without the possibility of establishing its 

 direction and magnitude; that the U. S. Geological Survey, in collaboration 

 with the California universities and geological societies, be invited to organ- 

 ize geologic studies of the regions in which the more active faults occur; 

 that the California Institute of Technology, the Mount Wilson Observatory, 

 the U. S. Bureau of Standards (Washington), and any others interested, be 

 invited to aid in the development of instruments more suitable than any now 

 in use for recording and analyzing local slips and tremors; and finally, that the 

 effort be made to obtain from the Navy Department deep-sea soundings off 

 the west coast of California to establish the precise location of the conti- 

 nental shelf and any other conspicuous fault scarps adjacent to the land areas 

 in which active faults are found. 



These recommendations were considered favorably and this committee was 

 asked to continue its organization for another year for the purpose of arrang- 

 ing with the institutions mentioned a practicable basis of cooperation through 

 which the various desiderata named above might best be accomplished. 

 This task was accepted by the committee, and during the past year an effort 

 has been made to organize working arrangements through which the proposed 

 plans may be carried out. Just here it may appropriately be said that with- 

 out a single exception every institution invited has been glad to join in a 

 systematic study of this kind and readj'- to aid to the fullest extent of its 

 power, and the organization — the first, be it said, of this magnitude which has 

 been attempted in American research — promises to be a most effective one. 

 This is a tribute not only to the scientific soundness of the problem under 



