I can put in personal experience on this from Loma Prieta quake.
Transportation gets pretty screwed up when the road has a 2.5 foot
vertical jumps. Dozers were needed to correct the problems and there
were enough breaks on the major through fare though the mountains that
it took a full week to doze access to people on that route. There were
probably around 30 locations that the road was just broken. If there
was fiber at the time, that would have probably been a LOT of breaks...
On 02/25/2019 08:43 AM, Bill Prince wrote:
Doesn't necessarily work after an earthquake. Roads, bridges, and so on
are "unavailable" after an earthquake. You might not be able to get to a
site, and/or the damage is so extensive, you need equipment that can't
get to the site.
We've had earthquakes with significant horizontal displacement, and the
microwave links have remained functional. Sometimes we've seen minor SNR
dropoff, but not in most cases.
I would make the argument that each can be a backup for the other. If a
link is really important, having multiple paths (microwave AND fiber) is
probably a better argument.
--
bp
part15sbs{at}gmail{dot}com
On Mon, Feb 25, 2019 at 8:31 AM <[email protected]
<mailto:[email protected]>> wrote:
I know I can throw a temp chunk of fiber on the ground and have
things up
and running in an hour or two.
-----Original Message-----
From: Robert
Sent: Monday, February 25, 2019 9:23 AM
To: [email protected] <mailto:[email protected]>
Subject: Re: [AFMUG] Earthquake Fiber vs Microwave
I would think that depends hugely upon the geography of the fiber run.
Fault zones in california can shift 9-12 feet in very tight shear in a
big one. Look at some of the pictures from the last quake in AK and
you can see 15-18 foot displacements in x y and z. Would be tough to
have confidence that your fiber would not get sheared in those
conditions. Might be tough to have a microwave link survive that as
well but if the tower isn't 100 feet tall and is anchored in bedrock
might not have as much trouble. I don't know of any towers that went
down in the Loma Prieta quake, the last large one I experienced. But
there might be some people on this list that have more data on that.
On 2/25/19 8:10 AM, [email protected] <mailto:[email protected]> wrote:
> Trying to make the case that underground fiber will survive an
earthquake
> better than mountain top microwave for public safety uses.
>
> -----Original Message----- From: Seth Mattinen
> Sent: Monday, February 25, 2019 9:07 AM
> To: [email protected] <mailto:[email protected]>
> Subject: Re: [AFMUG] Earthquake Fiber vs Microwave
>
> On 2/25/19 7:07 AM, [email protected] <mailto:[email protected]> wrote:
>> Anyone have some stories, perhaps from Alaska on earthquake
survivability
>> of fiber and microwave?
>> I have to go to a meeting with some lawmakers later in the week
to make
>> the case that fiber has some slack, fiber can be fixed quickly.
Towers
>> can tilt or tumble. Antennas can get misaligned. And sometimes
it is
>> impossible to get to a snowy peak for a weak during a storm.
>> Fiber is scalable. Microwave can be jammed and intercepted.
Etc etc.
>> Trying to be truthful and not gaslight anyone.
>
>
> Just make sure your fiber doesn't run in conduit attached to any
Cypress
> Street Viaduct like structures.
>
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