Date: Fri, 12 Mar 2004 08:39:11 -0800
From: Pascal Willis <Pascal.R.Willis@jpl.nasa.gov>
To: Martine Feissel <feissel@ensg.ign.fr>
Cc: Jean-Francois Cretaux <cretaux@cnes.fr>, John Ries <ries@csr.utexas.edu>,
    Ramesh Govind <Ramesh.Govind@ga.gov.au>,
    Adèle Guitart <Adele.Guitart@cnes.fr>,
    Herve Fagard <herve.fagard@ign.fr>,
    Serguei Kuzin <skuzin@inasan.rssi.ru>,
    Jean-Michel Lemoine <Jean-Michel.Lemoine@cnes.fr>,
    Jean-Jacques Valette <valette@cls.fr>,
    Jean-Paul Berthias <Jean-Paul.Berthias@cnes.fr>,
    Pascal Willis <Pascal.R.Willis@jpl.nasa.gov>, lebail@ensg.ign.fr,
    Zuheir Altamimi <altamimi@ensg.ign.fr>,
    Urs Hugentobler <urs.hugentobler@aiub.unibe.ch>,
    Petr Stepanek <pste@centrum.cz>,
    Jean-Pierre Granier <Jean-Pierre.Granier@cnes.fr>,
    Gilles Tavernier <Gilles.Tavernier@cnes.fr>
Subject: DORIS break in STJB

Dear Martine,

I think there could still be a missing break in the DORIS time series 
that is not mentioned and for which I would like to get some 
feed-back from the other Analysis Centers and/or from the SIMB :

January 20, 2003 	STJB	-1.7 cm in vertical

The change is small and hardly visible in the time series (see 
attached plot of residuals before putting any break) but without a 
break the estimated vertical velocity is -10 mm/yr, while with the 
break it goes down to -5 mm/yr and the residuals series has much less 
signal in it. The fact that the estimated horizontal displacements 
are within 1-2 mm makes me now think that this vertical discontinuity 
may be real.

I am not aware of any hardware intervention at this site from the SIMB.

If there is some agreement with the other Analysis centers, I could 
consider resubmitting the DORIS time series since 2003/1/20 with the 
correct DOMES description in the data file, if needed.

I have no problem with the other information in file 
doris_breaks.sinex as this is exactly what I gave to Zuheir. But has 
it been confirmed by somebody else as suggested in my 2003 
presentation at the IDS workshop?

Best regards
Pascal

NB:
for Fairbanks the earthquake was on Nov 3, 2002
for Arequipa, the earthquake was on Jun 23, 2001

-- 
Pascal Willis
Jet Propulsion Laboratory, MS 238-646     Ph : 1-818-393-4748
4800 Oak Grove Drive                      FAX: 1-818-393-4965
Pasadena CA 91109                         Em : Pascal.R.Willis@jpl.nasa.gov
