Seismic code of buildings which survived the earthquake motion, recommended that the seismic ratio (seismic acceleration divided by the gravity acceleration) equal to 1/12 for the first floor and 1/8 for the floors above should be used in seismic design of buildings. The Committee proposed equivalent vertical forces much larger than the horizontal forces because vertical motion acted as impacts. This is believed to be the first known quantitative recommendation of design seismic forces in the history of seismic codes. The recommendation was adopted in Royal Decree No. 573 of April 29, 1915. The height of the buildings was limited to two
Seismic array analyst's work. However, to obtain automatic time picks and thereby provide a slowness estimate automatically, techniques like cross-correlation or just picking of peak amplitude within a time window may be used. Because of the amount of required computations, plane wave fitting is most effective for arrays with a smaller number of sites or for subarray configurations. Current seismic arrays worldwide: YKA or Yellowknife Seismological Array is a medium size seismic array established near Yellowknife in the Northwest Territories, Canada, in 1962, in cooperative agreement between the Department of Mines and Technical Surveys (now Natural Resources Canada) and the United Kingdom