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 interferometry filtering can reduce but not eliminate the occurrence of multiples in a given dataset. Although there have been many advancements in seismic interferometry challenges still remain. One of the biggest remaining challenges is extending the theory to account for real world media and noise distributions in the subsurface. Natural sources typically do not comply with mathematical generalizations and may in fact display some degree of correlation. Additional problems must be addressed before applications of seismic interferometry can become more widespread. Seismic interferometry Interferometry examines the general interference phenomena between pairs of signals in order to gain useful information about the