ANURIMA MISHRA
Hello,
I have downloaded several sac files for an event. The sac files contain
BHE, BHN for some stations and BH1, BH2 for others. When I am rotating the
BHE,BHN components, they are rotating fine, but the BH1 BH2 are not. After
rotation, I could see that both the components are looking similar, which
should not be the case if rotated fine. I have checked the header. I could
not find any unusual parameter. I am attaching the pdf files for BH1, BH2
components for a station TIXI (network IU) and BHE, BHN components for a
station GTA (network CB). I am also attaching the raw sac files for both of
these stations.
Waiting for your reply.
Cheers
Anurima Mishra
Senior Research Fellow
Department of Earth Sciences
Indian Institute of Technology, Bombay
400076
Maharastra, India
I have downloaded several sac files for an event. The sac files contain
BHE, BHN for some stations and BH1, BH2 for others. When I am rotating the
BHE,BHN components, they are rotating fine, but the BH1 BH2 are not. After
rotation, I could see that both the components are looking similar, which
should not be the case if rotated fine. I have checked the header. I could
not find any unusual parameter. I am attaching the pdf files for BH1, BH2
components for a station TIXI (network IU) and BHE, BHN components for a
station GTA (network CB). I am also attaching the raw sac files for both of
these stations.
Waiting for your reply.
Cheers
Anurima Mishra
Senior Research Fellow
Department of Earth Sciences
Indian Institute of Technology, Bombay
400076
Maharastra, India
-
Hi Anurima,
BHN and BHE are oriented in the North and East direction respectively.
But BH1 and BH2 must be oriented with angles greater than 5 degrees from
North and East respectively.
I invite you to read the page 134 of SEED Manual (
http://www.fdsn.org/pdf/SEEDManual_V2.4.pdf)
In your particular case for TIXI station the azimuth is 0 for channel BH1,
(so coincides with BHN and so on).
HTH,
Milton
************************************
Milton P. PLASENCIA LINARES
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
Borgo Grotta Gigante 42/C
(34010) Sgonico - Trieste - Italia
Tel: +39 040 2140 156 (Udine)
Tel: +39 040 2140 256 (Trieste)
Cell.: +39 331 6481 935
E-mail: mplasencia<at>inogs.it
Antarctic Seismographic Argentinean Italian Network (ASAIN)
**************************************
On Fri, 5 Jun 2020 at 22:03, ANURIMA MISHRA (via IRIS) <
sac-help<at>lists.ds.iris.edu> wrote:
Hello,
I have downloaded several sac files for an event. The sac files contain
BHE, BHN for some stations and BH1, BH2 for others. When I am rotating the
BHE,BHN components, they are rotating fine, but the BH1 BH2 are not. After
rotation, I could see that both the components are looking similar, which
should not be the case if rotated fine. I have checked the header. I could
not find any unusual parameter. I am attaching the pdf files for BH1, BH2
components for a station TIXI (network IU) and BHE, BHN components for a
station GTA (network CB). I am also attaching the raw sac files for both of
these stations.
Waiting for your reply.
Cheers
Anurima Mishra
Senior Research Fellow
Department of Earth Sciences
Indian Institute of Technology, Bombay
400076
Maharastra, India
----------------------
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Thank you very much fro your reply Milton. My confusion was, similar
looking BH1 and BH2 after rotation, when they should look more like a
mirror image of each other. Which is not the case for TIXI as we can see.
But for GTA, the SH and SV are deflecting in opposite direction after
rotation, as the components for GTA were BHE and BHN. The manual you sent
was really helpful, as it showed that there could be a polarity reversal in
the signals while recording. I believe, I need to revert the polarity of
one component to get the useful signal after rotation.
Cheers
Anurima
On Sat, Jun 6, 2020 at 3:14 AM Milton Plasencia (via IRIS) <
sac-help<at>lists.ds.iris.edu> wrote:
Hi Anurima,
BHN and BHE are oriented in the North and East direction respectively.
But BH1 and BH2 must be oriented with angles greater than 5 degrees from
North and East respectively.
I invite you to read the page 134 of SEED Manual (
http://www.fdsn.org/pdf/SEEDManual_V2.4.pdf)
In your particular case for TIXI station the azimuth is 0 for channel BH1,
(so coincides with BHN and so on).
HTH,
Milton
************************************
Milton P. PLASENCIA LINARES
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
Borgo Grotta Gigante 42/C
(34010) Sgonico - Trieste - Italia
Tel: +39 040 2140 156 (Udine)
Tel: +39 040 2140 256 (Trieste)
Cell.: +39 331 6481 935
E-mail: mplasencia<at>inogs.it
Antarctic Seismographic Argentinean Italian Network (ASAIN)
**************************************
On Fri, 5 Jun 2020 at 22:03, ANURIMA MISHRA (via IRIS) <
sac-help<at>lists.ds.iris.edu> wrote:
Hello,
----------------------
I have downloaded several sac files for an event. The sac files contain
BHE, BHN for some stations and BH1, BH2 for others. When I am rotating the
BHE,BHN components, they are rotating fine, but the BH1 BH2 are not. After
rotation, I could see that both the components are looking similar, which
should not be the case if rotated fine. I have checked the header. I could
not find any unusual parameter. I am attaching the pdf files for BH1, BH2
components for a station TIXI (network IU) and BHE, BHN components for a
station GTA (network CB). I am also attaching the raw sac files for both of
these stations.
Waiting for your reply.
Cheers
Anurima Mishra
Senior Research Fellow
Department of Earth Sciences
Indian Institute of Technology, Bombay
400076
Maharastra, India
----------------------
SAC Help
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SAC Help
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-
Milton Plasencia
