Strong motion earthquake accelerograms, digitized and plotted data, Volume I - Uncorrected accelerograms; Part F - Accelerograms IF086 through IF105, Accelerograms from the San Fernando, California, earthquake of February 9, 1971

Abstract

This issue continues the San Fernando accelerograms,and contains twenty records consisting of three records each from four buildings and eight ground level records. Some comments on these records and their digitizations follow. IF086. Vernon. CMD Building. The complete record of 78 seconds was digitized. IF087. Santa Ana. Orange County Engineering Building. The complete record of 81 seconds was digitized. IF088. Glendale. 633 E. Broadway, Municipal Services Building. The complete record of 44 seconds was digitized. An aftershock triggered the instrument a second time and on some early versions of this record the two triggerings were run together as one record of considerably longer length. In this issue the aftershock is not included, but will appear as a separate record at some later date. IF089, 90, 91. 808 South Olive St. Street, 4th and 8th Levels. All records continued for 2-1/4 minutes but were digitized for 59 seconds by which time the first aftershock had diminished. IF092, 93, 94. 2011 Zonal. Basement, 5th and 9th Floors. All records were digitized out to the end at 34 seconds. The instruments on the 5th and 9th floors several times responded with a very high frequency, about 80 cps, lightly damped oscillation not associated with the usual building acceleration record. This particular vibration mode of the instrument is probably initiated by an impact loading on the structure near the instrument. Such impacts arise from dislodged material or equipment, or safety devices operating in elevator mechanisms. Through these sections of the record, usually lasting one or two seconds, the true acceleration curve was assumed to pass through the center of the high frequency record. IF095, 96, 97. 120 North Robertson. Sub-basement, 4th and 9th Floors. The 4th floor record was digitized to 59-1/2 seconds and the other two to the record end at 67 seconds. High frequency instrument oscillations were recorded on the upper floors in this building, as in the above building at 2011 Zonal. The particular instrument on the 4th floor had a large amplitude at this frequency and consequently the selection of the central curve in this portion was more difficult than in the 9th floor record. IF098, 99, 100. 646 South Olive. Basement, 4th Floor and Roof. The complete 56 second records were digitized. IF101. Southern California Edison Co., Colton. This was a poor record, thoroughly over-exposed at between 9 and 11 seconds, where digitizing stopped. IF102. Fort Tejon The complete record of 10-1/2 seconds was digitized.