tiedown tensions during 16may10 earthquake

• time: 01:16:10 AST (puerto rican seismic net time for earthquake at moca)
  
• Location:
  
• earth quake:18.40 N, 67.07 w, 34 km west of Ao (5 km from moca)
• ao: 18.344289N 66.752778W
  
• Depth: 113 km
• az=57.339, dome=8.3825, ch=8.835. stationary during the earthquake (doing drift scans).
  

• The accelerometer definitely went off scale...

• The colored plots are the total tension on td12 (black), td4 (red), td8(green) in kips.
• The x axis is seconds since the reported time of the quake (34 km away).. 01:16:10 AST.
  
• Data is sampled once a second.
• Page 1: tiedown tension vs time
  
• TOP
• The kips in each tiedown vs time.
  
• MIDDLE:
• remove the median value for each tiedown an add 2 kip offsets for plotting.
• BOTTOM:
• Total tdkips on platform vs time (kips from all 3 tiedowns summed).
• Page 2: oscillation frequencies.
• data from times 40 to 150 seconds was transformed to measure the oscillation freq.
• The 3 colors are td 12 white, td4 red, td8 green.
• Two frequencies were found:
• .368 hz (2.7 seconds) this was seen in previous measurements.
• .291 hz (3.4 seconds). .291 hz is probably an alias from the 1 second sampling. The true freq is probably (.5 +(.5-.291)= .7 hz.
  

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