Randall and Meredith,

Here's a link to Jos=E9 Otero's dissertation which=20
describes in great detail the feedback-less optical design, the 'iSTS-1'.

"Development and Characterization of an=20
Observatory-class, Broadband, Non-Fedback,=20
Leaf-Spring Interferometric Seismometer"=20
http://proquest.umi.com/pqdlink?did=3D1855874141&Fmt=3D6&VType=3DPQD&VInst=
=3DPROD&RQT=3D309&VName=3DPQD&TS=3D1297644594&clientId=3D79356=20
(23MB)

Incidentally, in there is the experiment you=20
(Randall) were wanting someone to perform to=20
characterize anelastic effects in a seismometer spring.

Interesting design, which to some degree confirms=20
my contention that making a feedback design perform well is way easier.

A less-detailed paper on the instrument is in the=20
BSSA  v100, n2, p598.   In speaking with one of=20
the authors it was clear to me that its=20
temperature sensitivity is such that it would=20
need to go into a deep, temperature stable,=20
borehole.  However, that is facilitated by the=20
fact that it has no electronics at the sensor,=20
with the displacement signal able to be recorded=20
at the surface via optical fibers.

Regards,
Brett

At 11:19 PM 2/12/2011, you wrote:
>Meredith,
>    The instrument at the URL you indicate looks=20
> like a vertical seismometer.  In Jon's email
>to me I understood him to be talking about a=20
>horizontal one, since it was in the context
>of the tutorial I had written.  Incidently, I=20
>know his name doesn't have an h in it, and
>I mistyped Brent for Brett.  Am having trouble=20
>with 'fat fingers' on the little virtual
>keyboard of this=20
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