tiedown tensions during earthquake
There was a 4.9 earthquake on 11mar09
- time: 22:05:35 AST
- Location: 19.045 N, 66.458 w (47 miles North of Ao (33 miles off
the north coast), 18.5 miles east of Ao.
- Depth: 14.7 km
The plot shows the tiedown tension vs time during
the earthquake (.ps) (.pdf):
- The colored plots are the total tension on td12 (black), td4
(red), td8(green) in kips.
- Data is sampled once a second.
- I've removed a linear baseline and put in offsets for display.
- The three plots cover:
- top 21:54 to 22:12 Ast.
- middle:22:00 to 22:12.
- bottom:22:04:32 to 10:07:12 and smooth the data by 9
- Every two minutes the distomats are measured and cause some
ringing in the tiedown tensions.
- 22:05:35. puerto rican seismic net time of earthquake.
- 22:05:50. dashed blue line. Seismometer at AO starts to move.
- 22:06:07 td 8 hits first minimum
- 22:06:20 td 8 hits first maximum
- 22:06:37 td 4 hits first maximum.
- The td8 oscillation took about 25 seconds.
- When the earthquake hit the telescope position was: az=148.8 deg,
za=12.94 deg. This is perpendicular to td8.
- The total tension in the tiedowns were:166 kips with td
12:70.9, td 4:47.46,and td 8: 47.48