[76767] in North American Network Operators' Group
Re: Any net disruptions from Indonesia quake / Tsunami?
daemon@ATHENA.MIT.EDU (Valdis.Kletnieks@vt.edu)
Mon Dec 27 02:01:08 2004
To: Joe Abley <jabley@isc.org>
Cc: George William Herbert <gherbert@retro.com>, nanog@merit.edu,
gherbert@kw.retro.com
In-Reply-To: Your message of "Sun, 26 Dec 2004 17:13:52 EST."
<6D12EB28-578B-11D9-88D7-000D93B24C7A@isc.org>
From: Valdis.Kletnieks@vt.edu
Date: Mon, 27 Dec 2004 01:59:54 -0500
Errors-To: owner-nanog-outgoing@merit.edu
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On Sun, 26 Dec 2004 17:13:52 EST, Joe Abley said:
> I'm no expert, but I'd imagine that any under-sea damage would be
> isolated to shallow approach to shore, and that the cable would be well
> below the wave action while the tsunami was in deep water. Cables are
> generally trenched pretty deep on the approach to shore as protection
> against dragging anchors, but I don't know what protection that would
> give against the undertow from a 10m-high wave.
News reports say the actual quake was a "thrust" fault - meaning that on the
one side of the fault line, the rock went down, and on the other it went up,
forming a cliff where it used to be flat.
The cables may be trenched near shore, and in deep water they're safe from wave
action - but if the cable happens to go across the fault line, the
carefully-laid no-slack cable is suddenly going literally off the edge of a
small underwater cliff. Even though it's got the tensile strength to allow
several miles to be dangling while they're laying the cable, a sudden yank like
that can't be good for it.
This of course only matters if the cable actually crosses the part of the
fault line that was in motion. I have no idea if any cables were in that
exact area....
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