International Federation of Digital Seismograph Networks

Thread: Re: proposal new blockettes

Started: Jan. 24, 2011, 4:41 p.m.
Last activity: Jan. 24, 2011, 4:41 p.m.
Sleeman, Reinoud (KNMI)
Jan. 24, 2011, 4:41 p.m.
Dear all,

As there are no more comments on Seiji's proposal for a new blockette -
2001 Delay Time Information Blockette - we can accept it. Also please
notice that the proposal for a Quartz Pressure Blockette has been withdrawn.

Best regards,


From: Seiji Tsuboi [tsuboi<at>]
Sent: Thu 1/13/2011 1:44
To: Sleeman, Reinoud (KNMI); fdsn-wg2-data<at>
Subject: RE: [fdsn-wg2-data] proposal new blockettes

Dear Reinoud

Thank you very much for your comments on our proposal.
We now have modified our proposal based on your comments.
I hope that this will suffice your concerns.

1)Delay Time Information Blockette

We slightly modified the delay time blockette.
We removed the field of ``data transferred path" and added variable comment
space for more general usage. It is necessary to contain the path
information in the delay time blockette because the delay time is sometimes
changed by the transfered path.

But this path information may be used for not only delay time but also other
purposes such as station and network information.

So, making another new blockette on the path information may be useful.

Instead of this, for the delay time blockette, we added comment space for
more general usage such as path information, cable status (for example,
cable connection/disconnection), starting date, and so on.

The blockette we propose here is data blockettes including next blockette's
byte number and is not linked with other blockettes.

2)Quartz Pressure Blockette

We discussed this blockette in our group.

We are going to use the quartz pressure gauge data in frequency domain only
in our group and not open the data, although we are going to open the time
domain data.

From this data policy, constructing new blockette on the quartz pressure
information may not be needed in the immediate future.

We here want to withdraw ``Quartz Pressure Blockette'' and examine the best
way of sending the information within our group.

Best regards,
Seiji Tsuboi

-----Original Message-----
From: Sleeman, Reinoud (KNMI) [reinoud.sleeman<at>]
Sent: Thursday, January 06, 2011 7:15 PM
To: Seiji Tsuboi; fdsn-wg2-data<at>
Subject: RE: [fdsn-wg2-data] proposal new blockettes

Dear WG-II members,

I believe the detailed explanation by Seji concerning the proposed new
blockette (2001) is
clear and answers the questions by Chad, Tim and Rick. However, in my
the use of
a letter code (AA, B1 etc) for the data transfered path should be
and described in
the SEED manual. Seji, can you please define the codes as you are using
them now ?
Apart from this I believe this blockette can be approved - if you have any
objection please
let us know within 2 weeks.

For the second item I do not see how the equation for pressure, which is
not a polynomial, could
be written in blockette 62. I believe it also requires values from 2
(U, T), right ? If
you have any suggestion/idea of how to incorporate such a complex equation
into a SEED blockette
let us know.

Best regards - and a happy new year to all of you !



From: fdsn-wg2-data-bounces<at> on behalf of Seiji Tsuboi
Sent: Wed 5/12/2010 4:35
To: fdsn-wg2-data<at>
Subject: Re: [fdsn-wg2-data] proposal new blockettes

Dear members of WG-II

I am sorry for late replies to the comments. We try to clarify our
in the following explanation. Please let us know if we need further

Thank you very much.
Seiji Tsuboi

1) This blockette documents components of the total time correction.
As you pointed out, data users do not need to perform any further
when encountering this blockette to determine sample times. This blockette
also enables us to derive more precise time information, which depends on
the frequency corresponding to the time unit (field 8,9,10), at each
data-transfer stage before applying time correction. We modified the
explanation of this blockette and temporarily named blockette 2001. Please
see the attached file.

2) To clalify the instrument what we are suing, we would explain some
The quartz pressure gauge we install outputs periods of temperature and
Data users need to use conversion equations and 14 conversion coefficients
if they analyze the data with physical value such as Pascal unit.
The conversion equations are as follows:

Temperature=Y1*U^1+Y2*U^2+Y3*U^3 (physical value)

U:Measured period of temperature (sensor output)

Pressure=C(1-T0^2/T^2)(1-D(1-T0^2/T^2)) (physical value)


T:Measured period of pressure (sensor output)
C1-C3, D1-D2, T1-T5:Coefficients

The coefficients are fixed for a given set of input samples.
For pressure, the equation is complex and is not a polynomial equation,
which may be different with an assumption of the Blockette 62 (Response
[Polynomial] Blockette).
Could you tell me whether we can extend or create a new field 7 of the
Blockette 62 for the above pressure equation?
We want to avoid the use of Maclaurin expansion because of the problem of
the precision of data conversion.
As another way, is it better to use the Blockette 62 to document the
coefficient and also use the Blockette 31 to explain the above complex

-----Original Message-----
From: fdsn-wg2-data-bounces<at>
[fdsn-wg2-data-bounces<at>] On Behalf Of Chad
Sent: Friday, April 23, 2010 6:15 AM
To: fdsn-wg2-data<at>
Subject: Re: [fdsn-wg2-data] proposal new blockettes

Dear WG-II,

Regarding the two proposed data blockettes:

1) The "Delay time Information Blockette" seems reasonable and we would
suggest that it be accompanied by a paragraph describing the intended
such as is done for blockette 405. We are assuming that is this is a
bookkeeping blockette that documents components of the total time
correction in field 16 of the fixed section data header, please let us
if we misunderstood the intention. The descriptive paragraph should
clearly state that data parsers do not need to perform any further
when encountering this blockette to determine sample times. A less
important characteristic is the usage of "10001" as a blockette type,
would recommended "2001".

2) We feel the proposal for a "Quartz Pressure Blockette" is too
being limited to a particular instrument type, a general solution would
be preferred.

Also it is not clear if the coefficients are changing continuously and
represent the actual data stream or are they fixed for a given set of
values. We ask the authors to clarify.

In the case where the coefficients represent the actual data an
solution might be the use of blockette 2000 which can contain nearly any

In the case where the coefficients are fixed for a given set of input
the question arises for why this would be a data blockette instead of
as a station control header blockette. Blockette 62 could potentially
extended by defining a new response type (equation), similar to the
for the MacLaurirn pressure sensors, and create a new field 7.

Chad Trabant
Tim Ahern
Rick Benson

On Apr 21, 2010, at 12:22 PM, Sleeman, Reinoud (KNMI) wrote:

Dear WG-II members,

I received the following request from JAMSTEC for 2 new blockettes
including a detailed description (see attached file):


One is ``Delay time Information Blockette" which describes breakdown
delay time. The other is ``Quartz Pressure Blockette" which includes
to convert count value of quartz-type pressure gauge data to physical

1. ``Delay time Information Blockette"
We are going to install some seismometers and quartz-type pressure
in seafloor this year.
The clock time of seafloor data stamped at land base station is
from the time in seafloor
observation because of the delay of time from sensor to seafloor
node point of optic submarine
cable, and the land base station.
This time difference is corrected in the land base station, and the
correction is written in field
16 (100 micro-sec unit) in Fixed Section of Data Header.
We here want to describe the breakdown of total delay time in SEED and
to utilize the system check of
data transfer and the acquisition of more precise (more than 100
precision) time at sensor in
We want to define the new blockette on delay time for seafloor

2. ``Quartz Pressure Blockette"
We observe water pressure using quartz-type pressure gauge
(Paroscientific, Inc.).
This gauge is monitoring not only water pressure but also temperature
in frequency domain for high-
accuracy measurement.
Data user needs to use conversion equations and 14 conversion
if they analyze the data with
physical value such as Pascal unit.
We want to define the new blockette on the coefficient for quartz-type
pressure gauge.


I'm not an expert in this type of measurements but the proposed
seems OK for me
within the SEED format. Please give me your opinion, if any. If there
are no objections within 3
weeks I will approve this proposal.

Best regards

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