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Intro:

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Links:

• 13jan14: 6.4 magnitude earthquake north of arecibo. tiedown tension variations.
  
• 16may10: 5.8 magnitude earth quake 34 km from AO. tiedown tension variation.
  
• 11mar09: earthquake causes td8 tension to vary.
  
• 11mar06: oscillations seen in cbh total power while tracking the crab.
  This shows many oscillation frequencies. Those measured during the hurricanes plus a few others. The interesting thing is that some of the oscillation frequencies are changing with hour angle (az,za) as we track the source (the .55 hz frequency seen during the hurricanes changes with az,za while the .35 Hz does not).
• 1.2 Hz oscillations caused by the refrigerator crossheads.
• 19may05: lbw
• 17oct04: sbn
• 29sep04: cband
• 15sep04: platform oscillations measured during tropical storm jeanne
  This used the load cell on Td12 (1hz). The other tiedowns had lost power.
• 12aug04: technicians felt large oscillations in the dome while tracking at low za.

This may have had something to do with the hydraulic brakes which require large torques to move downhill at low za (since there is no gravity).
• 21sep98: platform oscillation frequencies measured during hurricane georges:
  This used the tilt sensors in the dome (5 hz sampling) and the tiedown load cells (1hz).

 

Earthquake info.

AO seismic station.

• http://redsismica.uprm.edu/Spanish/
• Use the spanish version, english one doesn't work (fuego popular...)
• click on Monitoreo do estaciones
• scroll button on mouse to enlarge map, click on AO location
• or try this link: http://www.prsn.uprm.edu/Spanish/EstacionesV3/station_description.php?STAT=AOPR&INDEX=159&refresh=2
• Plot/device recording  Names:xyz-PR (see seed Manual).
  
• x- This specifies the bandwidth of the recoding device.
• B broad band
• 10<=sampling rate < 80 hz 8
  
• corner period >=10 secs
• H high broad band
• 80<= sampling rate < 250 Hz
• y- Instrument type code
• H - High gain seismometer
• L  - low gain seismometer
• ..
• N  Accelerometer
• z - Orientation code for the instrument
• Z - vertical
• N - north/south
• E - east/west
• BHZ plots
• 10-80 hz sampling
• accelerometer
• vertical motion
• HNZ plots
• 80-250 hz sampling
• accelerometer
• vertical motion
  

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