GNS ACCELEROGRAM DATA FILES

                             Standard Format

                        W J Cousins  (22 January 2008)


Each accelerogram data file contains heading data and accelerations for three
orthogonal component directions. Corrected accelerograms also contain velocity
and displacement signals calculated from the digitised acceleration record.

Horizontal components normally correspond to the longitudinal and transverse
accelerometer axes, although for some cases other directions may be selected.

For each of the three components, the file structure is as follows:


A.  Alphanumeric heading.

16 lines, maximum of 80 characters/line


B.  40 integer heading values.

4 lines, 10 integers/line (Fortran input format: 10I8)

     1   event origin (UT) .. year,
     2   .. month,
     3   .. day,
     4   .. hour,
     5   .. minute, and
     6   .. seconds x 10
     7   NZ seism obs log number (obsolete)
     8   aftershock number (obsolete)
     9   buffer start time (UT) .. year,
    10   .. month,

    11   epicentral latitude S, .. degrees,
    12   .. minutes, and
    13   .. seconds
    14   epicentral longitude E, .. degrees,
    15   .. minutes, and
    16   .. seconds
    17   hypocentral depth (km)
    18   centroid depth (km)
    19   buffer start time (UT) .. day,
    20   .. hour,

    21   site latitude S, .. degrees,
    22   .. minutes, and
    23   .. seconds
    24   site longitude E, .. degrees,
    25   .. minutes, and
    26   .. seconds
    27   longitudinal axis bearing (degrees E of N)
    28   component direction (degrees E of N)
    29   site-epicentral bearing (degrees E of N)
    30   epicentral distance (km)

    31   number of .. digitised samples,
    32   .. prepended samples,
    33   .. appended samples,
    34   .. acceleration samples,
    35   .. velocity samples, and
    36   .. displacement samples
    37   unused
    38   unused
    39   buffer start time (UT) .. minute,
    40   .. seconds x 1000


C.  60 floating-point heading values.

6 lines, 10 real numbers/line (Fortran input format: 10F8.0)

     1   instrument frequency (hz)
     2   ratio of critical damping
     3   film speed (mm/s) (MO film recorder)
     4   scale factor to mm on film (MO film recorder)
     5   inverse sensitivity (g/mm) (MO accelerometer)
     6   deviation angle 1 (radians) (MO accelerometer)
     7   deviation angle 2 (radians) (MO accelerometer)
     8   factor to give unit of mm/s/s
     9   timing lamp offset (never implemented)
    10   time of common timemark (s) (never implemented)

    11   site latitude, degrees S
    12   site longitude, degrees E
    13   epicentral latitude, degrees S
    14   epicentral longitude, degrees E
    15   local magnitude (Ml)
    16   surface-wave magnitude (Ms)
    17   moment magnitude (Mw)
    18   body-wave magnitude (Mb)
    19   unused
    20   unused

    21   digitised duration (s)
    22   prepended duration (s)
    23   appended duration (s)
    24   record duration (s)
    25   orig sampling interval (s)
    26   sampling interval (s)
    37   unused
    28   unused
    29   unused
    30   local g (mm/s/s)

    31   peak unfiltered acceleration (mm/s/s)
    32   time of above (s)
    33   rms unfiltered acceleration (mm/s/s)
    34   unused
    35   unused
    36   peak filtered acceleration (mm/s/s)
    37   time of above (s)
    38   rms filtered acceleration (mm/s/s)
    39   peak horizontal acceleration (mm/s/s)
    40   dominant filtered accel freq (hz)

    41   peak velocity (mm/s)
    42   time of above (s)
    43   rms velocity (mm/s)
    44   peak horizontal velocity (mm/s)
    45   dominant velocity frequency (hz)
    46   peak displacement (mm)
    47   time of above (s)
    48   rms displacement (mm)
    49   peak horizontal displacement (mm)
    50   dominant displacement frequency (hz)

    51   high-pass cutoff frequency (hz)
    52   high-pass transition frequency (hz)
    53   high-pass rolloff frequency (hz)
    54   unused
    55   unused
    56   low-pass rolloff frequency (hz)
    57   low-pass transition frequency (hz)
    58   low-pass cutoff frequency (hz)
    59   unused
    60   unused


D.  NPTA acceleration values, mm/s/s, 10 values per line

FORTRAN input format: 10F8.0



E.  NPTV velocity values, mm/s, 10 values per line

FORTRAN input format: 10F8.0
Not present in unfiltered accelerogram files.



F.  NPTD displacement values, mm, 10 values per line

FORTRAN input format: 10F8.0
Not present in unfiltered accelerogram files.




                 GNS RESPONSE SPECTRA DATA FILES

                        Standard Format


Each file contains header data, and acceleration, velocity and displacement
response spectra for three orthogonal component directions. Horizontal
components normally correspond to the longitudinal and transverse accelerometer
axes, although for some cases other directions may be selected. For each of the
three components, the file structure is as follows:


A.  Alphanumeric heading.

16 lines, maximum of 80 characters/line


B.  44 integer heading values.

4 lines, 10 integers/line, then 1 line of 4 integers
(Fortran input format 10I8)

     1   event origin (UT) .. year,
     2   .. month,
     3   .. day,
     4   .. hour,
     5   .. minute, and
     6   .. seconds x 10
     7   NZ seism obs log number (obsolete)
     8   aftershock number (obsolete)
     9   buffer start time (UT) .. year,
    10   .. month,

    11   epicentral latitude S, .. degrees,
    12   .. minutes, and
    13   .. seconds
    14   epicentral longitude E, .. degrees,
    15   .. minutes, and
    16   .. seconds
    17   hypocentral depth (km)
    18   centroid depth (km)
    19   buffer start time (UT) .. day,
    20   .. hour,

    21   site latitude S, .. degrees,
    22   .. minutes, and
    23   .. seconds
    24   site longitude E, .. degrees,
    25   .. minutes, and
    26   .. seconds
    27   longitudinal axis bearing (degrees E of N)
    28   component direction (degrees E of N)
    29   site-epicentral bearing (degrees E of N)
    30   epicentral distance (km)

    31   number of .. digitised samples,
    32   .. prepended samples,
    33   .. appended samples,
    34   .. acceleration samples,
    35   .. velocity samples, and
    36   .. displacement samples
    37   unused
    38   unused
    39   buffer start time (UT) .. minute,
    40   .. seconds x 1000

    41   number of viscous damping ratios (NDR) (usually 5)
    42   number of natural vibration periods (NVP) (usually 100)
    43   algorithm key  (0 => Duhamel Integral)
    44   total number of (interpolated) data samples used in response
         spectrum calculations


C.  60 floating-point heading values.

6 lines, 10 real numbers/line (Fortran input format: 10F8.0)

     1   instrument frequency (hz)
     2   ratio of critical damping
     3   film speed (mm/s) (MO film recorder)
     4   scale factor to mm on film (MO film recorder)
     5   inverse sensitivity (g/mm) (MO accelerometer)
     6   deviation angle 1 (radians) (MO accelerometer)
     7   deviation angle 2 (radians) (MO accelerometer)
     8   factor to give unit of mm/s/s
     9   timing lamp offset (never implemented)
    10   time of common timemark (s) (never implemented)

    11   site latitude, degrees S
    12   site longitude, degrees E
    13   epicentral latitude, degrees S
    14   epicentral longitude, degrees E
    15   local magnitude (Ml)
    16   surface-wave magnitude (Ms)
    17   moment magnitude (Mw)
    18   body-wave magnitude (Mb)
    19   unused
    20   unused

    21   digitised duration (s)
    22   prepended duration (s)
    23   appended duration (s)
    24   record duration (s)
    25   orig sampling interval (s)
    26   sampling interval (s)
    37   unused
    28   unused
    29   unused
    30   local g (mm/s/s)

    31   peak unfiltered acceleration (mm/s/s)
    32   time of above (s)
    33   rms unfiltered acceleration (mm/s/s)
    34   unused
    35   unused
    36   peak filtered acceleration (mm/s/s)
    37   time of above (s)
    38   rms filtered acceleration (mm/s/s)
    39   peak horizontal acceleration (mm/s/s)
    40   dominant filtered accel freq (hz)

    41   peak velocity (mm/s)
    42   time of above (s)
    43   rms velocity (mm/s)
    44   peak horizontal velocity (mm/s)
    45   dominant velocity frequency (hz)
    46   peak displacement (mm)
    47   time of above (s)
    48   rms displacement (mm)
    49   peak horizontal displacement (mm)
    50   dominant displacement frequency (hz)

    51   high-pass cutoff frequency (hz)
    52   high-pass transition frequency (hz)
    53   high-pass rolloff frequency (hz)
    54   unused
    55   unused
    56   low-pass rolloff frequency (hz)
    57   low-pass transition frequency (hz)
    58   low-pass cutoff frequency (hz)
    59   unused
    60   unused


D.  NDR (usually 5) viscous damping ratios.

Fortran input format: 10F8.0


E.  NVP (usually 100) natural vibration periods, s

Fortran input format: 10F8.0


F.  Spectral acceleration heading


G.  NVP spectral acceleration values, mm/s/s

Repeat for each of the NDR viscous damping ratios.


H.  Spectral velocity heading


I.  NVP spectral velocity values, mm/s

Repeat for each of the NDR viscous damping ratios.


J.  Spectral displacement heading


K.  NVP spectral displacement values, mm

Repeat for each of the NDR viscous damping ratios.


L.  Fourier Spectral heading


M.  NVP Fourier spectral values, mm/s