Terminology:

• Tower 8: the southwest tower
• cables m8-1..4  the 4 main cables that go from the platform corner to tower 8.
• back stay cables.There are 5 +2 cables that go from the top of the tower to the tower anchor.
  
• saddle: This sits on top of the tower. The main cables and back stay cable are terminated (socketed) in the saddle
• The main and back stay cables are separate cables, they are not a single cable.
• splice box: cable m8-4 (north cable of the 4).
• this cable came from the factory about 12' short.
• a 12' splice was added so the cable could reach the tower8
• The splice was added on the tower8 side of the cable
  
• the 12' splice was connected to the 600' cable using a 2' long splice box.
• The assumption is that both ends of the cable are socketed inside the splice box.
• diagram showing the suspension cable (with names) (.pdf)
• The Mxx cables are the main cables from corner of triangle to tower
• the Aux-M cables were added during the gregorian upgrade (2 to each tower).
• the A-NN  cables are the back stay anchor cables from top of tower to anchor (5 original)
  
• There are 2 aux cables added from tower to anchor during the gregorian upgrade.
• 
  

The earthquake: (top)

• a 6.4 magnitude earthquake occurred on 13jan14 at 00:01:05 AST
• Location:
• epicenter: 19.1385N, 66.8231W (82.19 Kn north-northwest of the city of Arecibo)
• AO coord: 18.344289N, 66.752778W
•   The puerto rican seismic network  accelerometer located at AO showed the earthquake:
  
• Each line is  15 minutes section. AST labels on left, UTC labels on right.
  
• 13nov14 BNZ (vertical motion 10-80hz) plot (.pdf)
• 13nov14 HNZ (vertical motion 80-250hz) plot (.pdf)
• plot from juan carlos morales..vertical, and ew, ns horizontal accelerations (.jpg) 
• HNN  north/south, HNE east/west, HNZ vertical.
  
• The tiedown tensions registered the quake about 25 seconds after the epicenter time (more in info on tiedown tensions during the quake)
  
• The total tension  measured by the tiedown loadcells decreased by 800 lbs after the quake oscillations had damped out.
• The telescope was moving when the quake it. When the quake arrived at AO, the telescope position was:
• az=48 deg (dome side of azimuth)
• zadome=11.8deg
• ch=8.8 deg
• the azimuth arm is aligned with tower 8 when the az=62 degrees.
• One of the cables from the platform to tower 8 (m8-4 .. outer cable on north side) suffered 10 broken strands.
• This is the "short" cable (about 12') that had a splice added at the tower side. This was done at the AO construction
• A splice box joins the long 600' cable with the 12' cable to reach the tower.
• This is also the cable that had its ubolt cut during the gregorian upgrade.

The cable m8-4 with broken strands  (top)

• 10 broken strands were found via visual inspection on the 12' splice cable.
• the breaks look to have occurred inside the splice box.
• there are about 140 strands in the 3" cable.
  
• one of the tower 12 back stay cables was replaced around 1981. it had 6 broken strands.
  

General view pictures of the saddle at tower 8 and the splice box.

• taken 17jan14 after the damage (.jpg)
  
• the saddle is on the right
• the closest cable (with the rain cover) is the damaged short splice cable.
• The cable with the ubolt at the top is one of the cables that supports the catwalk/cable car.
  
• the white box on the left is part of the splice box.
• The 5 cannisters on the top of the saddle are the button sockets for the back stay cables that go down to the t8 anchor.
• I think the person in the foreground is Vinnie from Amman and Whitney
• The cable be vinnie's knee is one of the aux main cables from T8 to the platform
• The aux main cable is connected to the collar truss that was added during the gregorian upgrade.
• taken 02mar11 (.jpg) . This is before the damage occurred.
• the splice box is not visible in this picture.
• You can see the condition of the short splice cable 3 years before the damage.
• A picture of the splice cable as it enters the saddle slot(.jpg) (taken 17jan14?)
• At the far end is the button socket the keeps the cable from sliding out of the slot in the saddle.
• Pictures of the downhill side of splice box (where the 600' long cable exits the splice box.
• down hill splice box looking from underneath (.jpg)
• down hill splice box looking at the top of cable (.jpg)
• You can see an air gap as the cable enters the splice box.
• Felipe told me these pictures were taken during the 2011 condition survey.
  

Images of cable 14jan14.. closeups of splice cable as it enters splice block.

    These pictures were taken on the morning of 14jan14 during the first inspection of tower 8 after the earthquake (13jan14 was a holiday).

• most of these pictures show the 12' spliced cable on t8 (m8-4) as it enters the splice box. 
• The splice is about 12' from the saddle of tower 8.
  
• The splice box connects the long 600' piece of m8-4 with the 12' splice (that broke)
• The metal hood above the damaged cable is a rain hood
• I think a few of the pictures show the splice cable on the tower side of the short cable.
  

fixing the cable (top)

• 21jan14: A&M drawing of what they think is in the splice box (.pdf)
• we have not been able to find a drawing of the interior of the splice box. 
• The repair was completed on 11mar14.
  

Amman and Whitney memos:

• 18feb14: cable damage report (.pdf)
• 11mar14:  M8-4 jumper installation approval (.pdf)