The National Strong-Motion Instrumentation Network ( NSMIN ) ( a cooperative effort including the United States Geological Survey and other organizations ) also monitored a set of 52 strong motion stations in the Los Angeles area . Most of the stations successfully captured the event , and the closest unit to the mainshock , a rock site at Garvey Reservoir , recorded a peak horizontal acceleration of .47 '' g '' . A twelve-story steel frame building in Alhambra was outfitted with accelerographs in the basement , at mid-level , and at the top of the structure . The top floor instruments recorded a peak acceleration of .18 '' g '' during the 1971 San Fernando earthquake and instruments on the sixth floor recorded a peak acceleration of .47 '' g '' at the time of the Whittier mainshock . A ten-story reinforced concrete building in Whittier ( 7215 Bright Ave. ) saw a peak horizontal reading of .63 '' g '' in the basement
1971 San Fernando earthquake
1971 San Fernando earthquake
1987 Whittier Narrows earthquake