Thread: Issues with resp files for some data IRIS DMC

Yes, I have included frequency limits.
In this case, I have attempted for a frequency range of 5 - 50 Hz
considering on the sensor's natural frequency and flat response given in
IRIS site (
http://www.iris.washington.edu/mda/YA/LOT1/01/EGE?timewindow=2001/02/13%2000:02:25-2001/02/22%2011:40:51).


I have also attempted with different frequencies. However, the amplitudes
of acceleration are as large as 2.0E15 NM/S/S.

A note on the data and my request:
-----------------------------------------------------
The above link would give aftershocks (well clustered) data recorded at a
station having about 50 - 80 km epicentral distances.
The magnitudes are ~ M 2.0 - 5.0. (more details can be found from this
paper and its supplement:
http://www.ceri.memphis.edu/people/shorton/AFTERSHOCK/bhuj1.pdf).

My current interest is to identify the specific aftershocks based on their
peak accelerations.
Thus, the unrealistic amplitudes obtained after removing instrument
response are not helping.
Few of my collaborators suggested that the response file and poles and
zeros seem to be wrong.

Despite the trouble, I wish if someone could try to get the data from above
link and find a way to obtain more realistic signals.

I sincerely appreciate the help. Thanks.

--
Thulasiraman







On Mon, Aug 17, 2015 at 5:17 PM, Arthur Snoke <snoke<at>vt.edu> wrote:

Have you included freqlimits? (
http://ds.iris.edu/files/sac-manual/commands/transfer.html).

I think in the past, attachments were allowed but only up to a specified
maximum total size. I am not sure what the rules are since the listserv
was ported to another server. However, you can always include the text
from a sample run.

Your link was no use.

On Aug 17, 2015, at 1:25 AM, Thulasiraman Natarajan <geothulasi<at>gmail.com>
wrote:

Dear members,

I am trying to use IRIS DMC data from "Bhuj aftershock study" network.
(http://ds.iris.edu/gmap/YA?timewindow=2001-2001).

My attempts with removing instrument response produced unrealistic
amplitudes for all the three components.

I followed these steps:
Downloaded mseed and dataless files
Extracted the SAC formated data and response files using rdseed
In SAC, read the data and removed the instrument response using following
steps,
* rmean
* rtrend
* taper
* transfer from evalresp <>

It seems the resp files generated using rdseed from mseed and dataless
files are incomplete / wrong.

Could someone help me with this issue?

PS: I could not attach files with this mail, hence, please look at the
given link for data.

--
Thulasiraman

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Dear Mary Templeton,

Thanks for your response.
It seems the instruments used were K2+episensor for acceleration and an
external Mark L28 for velocity.
I could get a better resp file for the episensor (Thanks to Milton
Plasencia) using the details mentioned in Bodin and Horton, 2004 BSSA. I
could get PGA values comparable to the values reported by them. I am okay
with this for my present work where I use the PGA values to pick weak and
strong motion events relatively.

However, it would be nice, if the correct resp files made available at
IRIS.

--
Thulasiraman

On Fri, Aug 28, 2015 at 5:02 AM, Mary Templeton <met<at>iris.washington.edu>
wrote:

Dear Thulasiraman,

Thank you for your email about the YA 2001 responses. I've
reviewed
the RESP files and had some questions as well. I'm Ccing the network
operator for this experiment - I think we need to know more about what
instrumentation was used in order to assess the instrument responses.

cheers,
Mary Templeton
IRIS DMC



On Aug 16, 2015, at 11:25 PM, Thulasiraman Natarajan <geothulasi<at>gmail.com>
wrote:

Dear members,

I am trying to use IRIS DMC data from "Bhuj aftershock study" network.
(http://ds.iris.edu/gmap/YA?timewindow=2001-2001).

My attempts with removing instrument response produced unrealistic

amplitudes for all the three components.

I followed these steps:
Downloaded mseed and dataless files
Extracted the SAC formated data and response files using rdseed
In SAC, read the data and removed the instrument response using

following steps,

* rmean
* rtrend
* taper
* transfer from evalresp <>

It seems the resp files generated using rdseed from mseed and dataless

files are incomplete / wrong.

Could someone help me with this issue?

PS: I could not attach files with this mail, hence, please look at the

given link for data.

--
Thulasiraman
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irisdmc-help<at>iris.washington.edu
http://www.iris.washington.edu/mailman/listinfo/irisdmc-help

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