SMC- and BBF-format Data Files

Table of Contents
=================
  1.0  Introduction
  2.0  Sample File
  3.0  Headers
       3.1 Text Headers
       3.2 Integer Headers
       3.3 Real Headers
       3.4 Comments
       3.5 SMC-format Headers Compared to BBF-format Headers
  4.0  Time Series Files
  5.0  Response Spectra Files
       5.1 Description
       5.2 Sample File
  6.0  Differences between SMC format version 2 and version 1
  7.0  File naming conventions 
       7.1  BAP output file names
       7.2  DDS#7 file names
  8.0  BAP Software
  9.0  Update History
 10.0  Technical Support


1.0  Introduction
=================
  
The strong-motion time series data served out by the U.S. Geological Survey
National Strong-Motion Program are in one of two formats, SMC or BBF. 
This documentaton describes the SMC-format and compares it to the BBF-format
headers.

The SMC format uses ASCII character codes and provides text headers, integer 
headers, real headers, and comments followed by either digitized time-series 
coordinates or, in version 2 of the SMC format only, sets of response spectra 
values. The header information is designed to provide the user with 
information about the earthquake and the recording instrument. Each SMC-format 
file contains either a single time series or a set of response spectra 
calculated or Fourier amplitude spectra of corrected acceleration from a 
single time series. Typical analog strong-motion records contain traces 
corresponding to three orthogonal components of motion and consequently 
require three separate SMC-format files to represent the record.

The BBF-format uses fixed-sized blocks of binary data. The first several 
blocks in each file are blocks that contain auxiliary information about the
time-series samples contained in the remaining blocks. Each file has a
minimum of two header blocks, the first of which contains 256 integer values 
and the second of which contains 128 real values. The time-series samples 
stored in the data blocks may be in either integer or real format. A text 
version of the BBF-format documentation can be obtained here 
http://nsmp.wr.usgs.gov/docs/bbffmt.txt.

This documentation was last updated on August 31, 2001.


2.0  Sample File
================
     Here follows a sample unevenly-sampled, uncorrected SMC-format 
time-series file from which most of the time series values have been 
removed:

1 UNCORRECTED ACCELEROGRAM                                                      
*                                                                               
DVD0D
     1989  10  18    0004 Loma Prieta, CA               
Moment Mag=      6.9 Ms=      7.1 Ml=      7.0
station = Del Valle Dam, toe             component=     65 
epicentral dist =     66.0       pk acc =     54.8                              
inst type=SMA-1      data source = CDWR/USGS                                    
*                                                                               
*                                                                               
*                                                                               
    -32768      1989       291         0         4         0    -32768       451
         1         3         6    -32768        90        65       101         8
     41320    -32768         3    -32768    -32768    -32768    -32768    -32768
    -32768    -32768    -32768         1    -32768      1265    -32768    -32768
    -32768    -32768    -32768    -32768    -32768    -32768    -32768    -32768
    -32768    -32768    -32768    -32768    -32768    -32768    -32768    -32768
  0.1700000E+39  0.1700000E+39  0.3703700E+02 -0.1218830E+03  0.1800000E+02
  0.7100000E+01  0.7100000E+01  0.7000000E+01  0.1700000E+39  0.1700000E+39
  0.3761500E+02 -0.1217450E+03  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.6600000E+02  0.1700000E+39  0.1000000E+05  0.1700000E+39
  0.1700000E+39  0.2540000E+02  0.6000000E+00  0.2000000E+01  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.9798830E+01  0.5482899E+02
  0.9609058E+01 -0.4761129E+02  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
|                                                                              
|  Put comments here.
|  Explain about any peculiarities in the record, any difficulties in 
|    digitizing, etc.
|  If no comments are necessary, place a single line with "|" in the
|    first column this section.
|  Set integer header cell # 16 = number of comment lines = 9 here.
|  <pltlbl=> Sample plot label here <end>
|                                                                              
 0.0000E+0 7.3789E-2 2.4847E-3 9.0424E-1 5.9633E-3 1.3411E+0 7.3548E-3 1.4865E+0
 8.8456E-3 1.6317E+0 1.0336E-2 1.8260E+0 1.1728E-2 2.1184E+0 1.3219E-2 2.5088E+0
 1.4610E-2 2.5071E+0 1.6101E-2 2.8484E+0 1.7492E-2 2.6996E+0 1.8983E-2 3.0409E+0
 2.0375E-2 3.2843E+0 2.1866E-2 3.2334E+0 2.3257E-2 3.3788E+0 2.4748E-2 3.2298E+0
 2.6139E-2 3.5223E+0 2.7630E-2 3.4714E+0 2.9121E-2 3.8127E+0 3.0512E-2 3.6148E+0
 3.2003E-2 3.7110E+0 3.3395E-2 3.6112E+0 3.4885E-2 3.6093E+0 3.6277E-2 3.3399E+0

    ... most of the time-series lines were removed here ...

 2.9598E+1 1.9508E+0 2.9599E+1 1.6998E+0 2.9600E+1 2.1248E+0 2.9602E+1 1.9473E+0
 2.9603E+1 2.1673E+0 2.9605E+1 2.2120E+0 2.9606E+1 2.3576E+0 2.9608E+1 2.5521E+0
 2.9609E+1 2.5016E+0 2.9610E+1 2.4020E+0 2.9612E+1 2.3024E+0 2.9613E+1 2.5459E+0
 2.9615E+1 2.4463E+0 2.9616E+1 2.4938E+0 2.9618E+1 2.3452E+0 2.9619E+1 2.6869E+0


3.0  Headers
============
     There are four types of headers in SMC format files: text headers, integer 
headers, real headers, and comments.  The 11 text header lines provide a little
prose designed to allow a user to identify quickly the earthquake and recording 
station.  Then follow 6 lines of integer header values and 10 lines of real 
header values. Following the text, integer, and real headers are a variable 
number of comment lines that can contain additional information about the
earthquake or the record.  Then follow either digitized time-series values or 
several sets of response spectra values.  The number of comment lines included 
in the file is indicated in the 16th integer header value and the number of 
time-series values is indicated in the 17th integer header value.

     Both the integer and real headers have many cells that contain a value that
indicates "undefined"; these cells are either filled in subsequent stages of 
data processing or are merely included in the file format so that more 
information can be added to future files without changing the format.  The 
value used to indicate "undefined" in integer header cells is usually "-32768"; 
the value used in real header cells is usually "+1.7e+38".

     The Fortran format for each integer header line is "(8I10)", for each real 
header line is "(5E15.7)", and for each time-series line is "8(pe10.4e1)".   
There are 6 integer header lines with 8 values per line, for a total of 48 
integer values.  There are 10 real header lines with 5 values per line for a 
total of 50 real header values.  There are 11 text header lines and there are 
as many comment lines as are indicated in integer header cell #16.


3.1  Text Headers     (fixed format)
=================
     There are 11 text-header lines in a SMC-format time-series data file.  
They have the following format:

     0        1         2         3         4         5  (columns for reference)
     12345678901234567890123456789012345678901234567890  (columns for reference)

     # <--- text ------------->
     *
     SSSSA
          YYYY  MM  DD    TIME <-- earthquake name here --------------------->
     Moment Mag=      #.# Ms=      #.# Ml=      #.#
     station = <--- station name here ------> component= ###
     epicentral dist =     ##.#       pk acc =    ###.# 
     inst type=SMA-1      data source = USGS/VVVV                     
     *
     *
     *

     12345678901234567890123456789012345678901234567890  ( <= columns)
     0        1         2         3         4         5  (      "    )


line 1:  Contains a number in column 1 followed by text in columns 3-26, both 
              of which indicate which type of data is contained in the file. The
              contents of the first line can be one of the following:
              "0 UNKNOWN"    (BAP will treat this like UNCORRECTED ACC)
              "1 UNCORRECTED ACCELEROGRAM" (Also referred to as Volume 1 data)
              "2 CORRECTED ACCELEROGRAM" (Volume 2)
              "3 VELOCITY" (Volume 3)
              "4 DISPLACEMENT" (Volume 4)
              "5 RESPONSE SPECTRA" (Volume 5)
              "6 FOURIER AMPLITUDE SPECTRA OF CORRECTED ACCELERATION" (Volume 6)
line 2:  "*" in column one
line 3:  Either a "*" in column one, or columns   1-4 = Station code
         column      5 = "A", "B", "C", ... to indicate which of the several
                         accelerometer traces on the record is digitized
                         in this file.  "A" is the topmost accelerometer trace, 
                         "B" is the second from the top, etc.
    Note: in files that come from the DDS#7 CD-ROM, columns 1-5 of line 3 should
                         correspond with the 5-character station-component code 
                         used in the file name.  See Section 7.2
line 4:  columns  1-3  = time zone if the time zone is other than GMT. This   
                         field will be blank in all the files on the CDROM(s).
                         But it may indicate a time zone other than GMT in some 
                         files created by the V2S reformatting program (which 
                         doesn't know how to convert from all the various time  
                         zones to GMT).                                 
         columns  6-9  = earthquake year (four digits)
         columns 12-13 =      "     month
         columns 16-17 =      "     day 
         columns 22-25 =      "     hour, minute in GMT
         columns 27-80 = earthquake name (left justified)
line 5:  columns  1-11 = "Moment Mag="
         columns 12-20 = moment-magnitude value
         columns 22-24 = "Ms="
         columns 25-33 = Surface-wave magnitude value
         columns 35-37 = "Ml="
         columns 38-46 = Local magnitude value
line 6:  columns  1-10 = "station = "
         columns 11-40 = station name, left justified
                         (Note:  Some files incorrectly have the station
                                 number instead of name in this field).
         columns 42-51 = "component= "  
                         (Note:  Some files have the "c" was in column 41 
                                 instead of column 42!
         columns 53-57 = orientation of the recording transducer
                         (Note:  There seems to be no convention for where
                                 the value is placed in these columns.)
line 7:  columns  1-17 = "epicentral dist ="
         columns 18-26 = epicentral distance in kilometers
         columns 34-41 = "pk acc ="
         columns 42-50 = peak value of the time series given in this file
line 8:  columns  1-10 = "inst type="
         columns 11-15 = "SMA-1" or "CRA-1" or whatever to indicate the type
                         of recording instrument.
         columns 22-34 = "data source ="
         columns 36-80 = an abbreviation indicating the agency that provided
                         the data.  "USGS", "CSMIP", etc.
lines 9, 10, and 11:  a "*" in column one.


3.2  Integer Headers     (48 values, 6 lines in "(8I10)" format)
====================
     The values given in integer header cells have the following meanings:

  cell
number   description
------   -----------
     1   Value representing "undefined" or "null" in the integer header. 
              This is usually (always?) set to  "-32768".
     2   Time of first recorded sample, year (4 digits),  GMT
     3                  "               day of year  (julian day)
     4                  "               hour
     5                  "               minute
     6                  "               second
     7                  "               millisecond
     8   Recorder serial number
     9   Channel number of the digitized trace given in this file.
              Channel numbers are counted sequentially, top-to-bottom,
              with the top-most accelerometer trace counted as #1.
    10   Total number of channels (=accelerometer traces) on this record.
    11   Total number of channels recorded at this station
    12   Sensor serial number
    13   Vertical orientation (degrees from up)   
              0 < integer cell #13 < 180, usually 0 (UP = 0, DOWN = 180).
              Null value should be used when sensor is a horizontal component.
    14   Horizontal orientation (degrees east of north)   
              0 < integer cell #14  < 360. Null value should be used
              when sensor is a vertical component.
    15   Sensor type code:
                2  Sprengnether SA-3000 3-component fba
               30  Kinemetrics FBA-13   3-component fba
               31  Kinemetrics FBA-11   1-component fba
              101  SMA-1                    125  Kinemetrics FBA-23
              102  C&GS Standard            126  Kinemetrics Episensor
              103  AR-240                   127  Kinemetrics FBA-4g
              104  RFT-250                  128  Kinemetrics FBA-2g
              105  RFT-350                  129  Kinemetrics FBA-1g
              106  MO-2                     130  Kinemetrics FBA-0.5g
              107  RMT-280                  131  Kinemetrics FBA-0.25g
              108  SMA-2/3                  132  Kinemetrics FBA-0.1g
              109  DSA-1/DSA-3              133  WR1
              110  DCA-300                  134  S6000
              111  DCA-333                  135  Mark Products L22
              112  A-700                    136  Products L4C
              113  SSA-1                    137  CMG3
              114  CRA-1                    138  CMG3T
              115  MO-2                     139  CMG40T
              116  FBA-3                    140  CMG5
              117  SMA-2                    141  KS-2000
              118  DCA-310                  900  custom instrument
              119  FBA-13                  1302  Reftek Model 130-ANSS/02 
              120  SSA-2
              121  SSR-1
              122  BIDRA
              123  CR-1
              124  PDR-1                    900  custom instrument
    16   Number of comment lines following the header information.
    17   Number of time-series values.  Note that the number of "values"
              specified here should be the number of time-series samples if the
              time series is evenly sampled, twice the number of samples if the
              time series is unevenly sampled (because two values, abscissa and
              ordinate, are given for each sample when the time series is 
              unevenly sampled).
    18   Problem flag -  This is usually set to "undefined", but if there is a
              problem with the record, such as spikes or unusual noise, or
              unusual noise, it should be set to 1, in which case additional
              information should be available in the comments section.
    19   Type of structure:  1 = building,  2 = bridge,
                             3 = dam,       4 = other,
                          null = not a structure.
    20   Structure number corresponding to printed information.
    21   Transducer number of the recording system as shown on the drawing.
    22   Total number of transducer channels for this structure.

    The following integer parameters are for buildings (when
           Integer cell #19 = 1):
    23   Number of floors above grade, including the roof.
    24   Number of stories below grade.
    25   Floor on which this sensor is located
              -1  1st subbasement, etc
               0  basement
               1  grade level
               2+ floor levels above grade

    The following are for bridges (when Integer cell #19 = 2):
    26   Number of spans
    27   Location of transducer
               0  free field
               1  at the base of a pier or abutment
               2  on an abutment
               3  on the deck at the top of a pier
               4  on the deck between piers or between an abutment and a pier

    The following are for dams (when Integer cell #19 = 3):
    28   Location of this transducer
               0  upstream or downstream free
                  field
               1  at the base of the dam
               2  on the crest of the dam
               3  on the abutment of the dam
    29   Type of construction
               1  Reinforced concrete gravity
               2  Reinforced concrete arch
               3  earth fill
               4  other
    30   Station number (This will be "undefined" if the station "number"
                        includes alphabetic characters, in which case it will be
                        indicated in the station name field in text header line
                        6.)
    31   First recorded sample.  This will be "undefined" or 1 if the first 
              recorded sample is the first sample given in the time series.
              (This info is required because the BAP software adds leading and 
              trailing zero pads to the time series before filtering.  BAP 
              output files may include these leading and trailing pad areas,
              which after filtering will contain small filter transients.  
              Integer header cells #31 and 32 indicate where the actual
              recorded time series begins and ends.)
    32   Last recorded sample. 
    33   Refer to another file flag.  If this not "undefined" it indicates that 
              users should refer to the file indicated in the second line of 
              the comments for more information about the data in the current 
              file.  Plotting programs like BAP and TSPLOT should display that 
              second comment line along with plots of this data.
    34-39   Undefined
    40-41   Reserved for user
    42-47   Undefined
    48   Clock source (Kinemetrics Altus)
              0  RTC (internal clock)
              1  Keyboard
              2  Sync with external reference pulse
              3  GPS (= -1 if a correction for GPS rollover beginning Aug. 23, 
                 1999, was made to original file time                   


3.3  Real Headers     (50 values, 10 lines in "(5E15.7)" format)
=================
     The values given in real header cells have the following meanings:

  cell
number   description
------   -----------

     1   Value representing "undefined" or "null" in the real header. This is
              usually set to "+1.7e+38".  The use of the "-0.3e-38" value found 
              in some older files on the USGS VAXes is not recommended because 
              that number is out of range and not acceptable to the floating-
              point representation used on PCs and most UNIX computers.
     2   Sampling rate (samples per second) for evenly-sampled time series;
              "undefined" for unevenly-sampled time series.
     3   Earthquake latitude (decimal degrees; "+" for Northern Hemisphere)
     4   Earthquake longitude (decimal degrees; "-" for Western Hemisphere)
     5   Earthquake depth (km relative to sea level)
     6   Source magnitude M   (moment magnitude)
     7     "        "     MS  (surface-wave magnitude)
     8     "        "     ML  (local magnitude)
     9     "        "     M   (other)
    10   Seismic moment (dyne-cm; 1 newton-meter = 10**7 dyne-cm)
    11   Station latitude (decimal degrees; "+" for Northern Hemisphere)
    12   Station longitude (decimal degrees; "-" for Western Hemisphere); some 
         files incorrectly have positive value here
    13   Station elevation (m relative to sea level)
    14   Station offset N (m)
    15   Station offset E (m)
    16   Station offset up (m)
    17   Epicentral distance (km)
    18   Epicenter to station azimuth (degrees east of north)
              0.0 < real header cell #18 < 360.0
    19   Digitization units (units/cm) for analog-recorded data;
              Digitizing constant (counts/volt) for digitally-recorded data.
    20   Undefined for analog-recorded data; anti-alias filter corner
              frequency (Hz) for digitally-recorded data.
    21   Undefined for analog-recorded data; anti-alias filter poles
              (6dB/octave per pole) for digitally-recorded data.
    22   Natural frequency of the sensor (Hz) 
    23   Sensor damping coefficient (fraction of critical)
    24   Recorder sensitivity (cm/g) for analog-recorded data;
              Coil constant (volts/cm/sec/sec) for digitally-recorded data.
    25   Undefined for analog-recorded data;  amplifier gain (dB) for
              digitally-recorded data.
    26   Undefined for analog-recorded data;  pre-amp gain (dB) for 
              digitally-recorded data.
    27   Undefined in version 2.  (Had been a suggested corner frequency
              for high-pass filter in version 1 SMC files.)
    28   Undefined in version 2.  (Had been a suggested corner frequency
              for low-pass filter in version 1 SMC files.)
    29   Time of the time-series maximum (largest positive) value (seconds)
    30   Value of the maximum value (cm/sec/sec, cm/sec, or cm)
    31   Time of the time-series minimum (largest negative) value (seconds)
    32   Value of the minimum value (cm/sec/sec, cm/sec, or cm)
    33-36 indicate transitions for low-cut and high-cut filters.
         For uncorrected (volume 1) time series provided by CSMIP, these four
              numbers indicate *suggested* transition bands to be used in the
              correction process. 
         For corrected (volume 2) time series, these four numbers indicate 
              the *actual* low-cut and high-cut filter transitions that were 
              used in the correction process.  
         The contents of real header cells 33 and 34 indicate the beginning and 
              End of a transition band, in Hz, for a low-cut filter when the
              contents of 34 is positive.  When the contents of 34 is negative, 
              however, its negated value indicates the roll-off parameter that 
              was used in the BAP or AGRAM bi-directional Butterworth filter 
              and the contents of 33 is the corner frequency, in Hz, that was
              used in the Butterworth filter.  (Note that the roll-off
              "parameter" indicated for the BAP & AGRAM Butterworth filter is 
              equal to half of what is often called the "order" of a 
              Butterworth filter.
         The contents of 35 and 36 indicate the beginning and the end of a
              transition band for a high-cut filter.
>>    >> IMPORTANT NOTE: If the contents of 33-36 are "undefined" in a Vol. 2
              or 3 file, the filtering scheme will be described in the comments
    37   Undefined
    38   Initial value of the filtered velocity (cm/s) after a lo-cut filter has
              been applied to the integrated, baseline-corrected acceleration.
    39   Initial value of the filtered displacement (cm) after a lo-cut filter has
             been applied to the doubly-integrated, baseline-corrected
             acceleration.
    40   Vs30 (m/s).
    41-50 are undefined as yet.



3.4  Comments
=============

     Comment lines begin, by convention, with a "|" character in colume one and
may be up to 80 characters long.  The comments often provide references to 
published documents that describe the earthquake, station, or some other aspect
of the record.  Comments are also used to explain any peculiarities in the 
record, any difficulties in digitizing, and so forth, especially when integer
header cell #18 (the problem flag) is set to one.  In volume 2 files, the
comments may provide information about the processing the time series has
received.

     The Comments may include text that can be used as top-of-plot labels when 
the time series in the file are plotted via the BAP or TSPLOT programs.  These 
labels are indicated in the comments by a leading "<pltlbl=>" or "<loclbl=>" 
and a trailing "<end>".  (Note that the <pltlbl=>, <loclbl=> and <end> must all
be in lower case.) Both types of top-of-plot label can be more than one line 
long.  Some sample comment lines that include top-of-plot labels:               
                                                                          
| This time series was digitized at the USGS on 12dec97 by Sam Spade.     
|   <pltlbl=> blah blah blah                                              
|             any number of lines here                                    
|             ending with:  <end>                                         
|   <loclbl=> roof, north-west corner <end>                               
| More general comments here.                                             
                                          
                              
The <pltlbl=> top-of-plot label is usually just one line that indicates the     
address or name of the recording station, if sufficient station identification 
would not fit on line 6 (colums 11-40).  The <loclbl=> label gives information 
about the location of the recording transducer.  It is usually quite short, and
in the case of tri-axial recordings it is usually absent because all three 
transducers are in the same location.  The <loclbl=> information is provided 
separately from <pltlbl=> info so the info unique to each transducer is separate
from the info several transducers share. (Makes construction the plot labels 
more convenient for the TSPLOT program.)                           

     When integer header cell #33 is not "undefined", the second line of the 
comments (the first line is usually just "|") will indicate a text file that 
will provide information about the data in the current file.  This feature was 
implemented for files from the California Strong-Motion Instrumentation Program
(CSMIP) and will probably not be used in files from other sources.              
     Integer header cell #16 indicates the number of comment lines in the file.


3.5 SMC-format Headers Compared to BBF-format Headers
=====================================================
     Here follows a probably incomplete list of where a given value is located
in SMC-format headers and BBF-format headers:

A) Integer headers:
   SMC  BBF
   ---  ---
     1    3     integer null value
     2   10     year(4 digits)  first sample time
     3   11     julian day        "     "     "
     4   12     hour              "     "     "
     5   13     minute            "     "     "
     6   14     second            "     "     "
     7   15     millisecond       "     "     "
     8   20     recorder serial number         
     9   28     recorder channel number:this file
    10   29     recorder channel number:total  
    11   30     number of channels recorded for this station
    12   40     sensor serial number
    13   41     vertical orientation (degrees from up) 
    14   42     horizontal orientation (degrees east of north) 
    15   43     sensor type code

B) Real headers:
   SMC  BBF
   ---  ---
     1    2     real null value 
     2    5     sample rate 
     3   10     earthquake latitude 
     4   12     earthquake longitude
     5   14     earthquake depth 
     6   15     source magnitude M 
    10   16     seismic moment 
    11   40     station latitude 
    12   42     station longitude 
    13   44     station elevation 
    17   19     epicentral distance(km)     
    18   20     epicenter to station azimuth
    19   46     digitizing constant (counts/volt) 
    20   47     anti-alias filter corner frequency
    21   48     anti-alias filter poles
    22   49     natural frequency of the sensor
    23   50     sensor damping coefficient     
    24   51     coil constant(volts/cm/sec/sec)
    25   52     amplifier gain(dB) for a DR100
    26   53     pre-amp gain(dB) for a DR100 


4.0  Time Series Files        8(1pe10.4e1)
======================

     Time-series values representing a single data trace from a strong-motion
record follow the header lines in a time-series file. The Fortan format for 
each line is "(8(1pe10.4e1))".  Eight values are given on each line, and there 
are as many lines as are required to provide the number of time-series values 
indicated in the value given in integer header cell #17.   For unevenly-sampled
time series (real header cell #2 is "undefined"), the values are given as a 
series of time-acceleration pairs; for evenly-sampled time series the values
are given as a series of evenly-sampled acceleration, velocity, or
displacement values, with real header cell #2  indicating the sampling rate.  
The number of time-series "values" given in the file and indicated in integer 
header cell #17 is the number of samples if the time series is evenly sampled; 
twice the number of samples if the time-series is unevenly sampled (because 
two values, time and acceleration are given for each sample when the time series
is unevenly sampled).  Time is given in seconds, acceleration in cm/sec/sec, 
velocity in cm/sec, and displacement in cm.


5.0  Response Spectra Files
===========================

5.1  Description
================

Lines 1-30:  The first 30 lines of a response spectra file contain the header
               info that corresponds to the acceleration time series that was
               used as input to the response-spectra calculations. Header cells 
               containing peak value, number of samples, and the like contain 
               values appropriate for the acceleration time series.  
Line 31:     indicates the units used for response values. The Fortran format 
               for this line is "3(i2,a15)".
               The numbers and units are as follows:
               1 cm                          2 inches
               1 cm/sec                      2 inches/sec
               1 cm/(sec squared)            2 inches/(sec squared)
Line 32:     indicates the number of damping values, the number of period
               values, and a times-are-included-or-not flag. The Fortran format 
               for this line is "(3i5)". The number of damping values is 
               referred to as NDAMP below and is usually 5.  The number of 
               period values (= the number of samples in each spectrum) is 
               referred to as NPER below and is usually 91.  The whether or not
               (1 or 0) times of maximum response are included in the file flag 
               is referred to as TFLAG below and is usually 0, indicating that 
               times are not included. (The times of maximum response, lines 
               43-48, are not provided in BAP output files, but they are given
               in some of the files that will be published in DDS#7 sequel 
               CD-ROMs.)
-------------------------------------------------
The usage "Lines" below refers to *sets* of lines
-------------------------------------------------
Lines 33:    NDAMP/5 (rounded up) lines listing the NDAMP damping values in
               "(5e10.5)" format.
Lines 34:     NPER/7 lines listing the NPER period values in "(7e11.4)" format.
--------------------
Lines 35 through 48 are repeated for each NDAMP damping value:

Line 35:     A header card containing "Relative Displacement Response Spectrum 
               at X% Damping" (where X is replaced by one of the NDAMP damping
               values).
Lines 36:    NPER/7 lines containing relative displacement response spectral
               values in "(7E11.4)" format.
Line 37:     A header card containing "Relative Velocity Response Spectrum 
               at X% Damping"
Lines 38:    NPER/7 lines containing relative velocity response spectral
               spectral values in "(7E11.4)" format.
Line 39:     A header card containing "Pseudo-Velocity Response Spectrum 
               at X% Damping"
Lines 40:    NPER/7 lines containing pseudo-velocity response spectral
               values in "(7E11.4)" format.
Line 41:     A header card containing "Absolute Acceleration Response Spectrum 
               at X% Damping"
Lines 42:    NPER/7 lines containing absolute acceleration response spectral
               values in "(6E13.6)" format.
>>             >> Programmers please note the different format.

Lines 43 through 48 are given only when TFLAG=1:
-------------------
Line 43:      A header card containing "Times of Maximum Response Relative 
               Displacement at X% damping"
Lines 44:    NPER/7 lines containing times of maximum response relative 
               displacement in "(7E11.4)" format.
Line 45:    A header card containing "Times of Maximum Response Relative 
               Velocity at X% Damping"
Lines 46:   NPER/7 lines containing times of maximum response relative
               velocity in "(7E11.4)" format.
Line 47:    A header card containing "Times of Maximum Response Absolute 
               Acceleration at X% Damping"
  Lines 48   NPER/7 lines containing times of maximum response absolute
               acceleration in "(7E11.4)" format.


5.2  Sample Response-Spectra File
=================================
     Here follows a sample BAP (version 2) response-spectra output file from 
which all but the first set of response spectra (the set corresponding to the 
first damping value) have been removed:


5 RESPONSE SPECTRA                                                              
*                                                                               
DVD0D                                                                           
     1989  10  18    0004 Loma Prieta, CA                                       
Moment Mag=      6.9 Ms=      7.1 Ml=      7.0                                  
station = Del Valle Dam, toe             component=     65                      
epicentral dist =     66.0       pk     =     53.7                              
inst type=SMA-1      data source = CDWR/USGS                                    
*                                                                               
*                                                                               
*                                                                               
    -32768      1989       291         0         4         0    -32768       451
         1         3         6    -32768        90        65       101         3
      5914    -32768         3    -32768    -32768    -32768    -32768    -32768
    -32768    -32768    -32768         1    -32768      1265    -32768    -32768
    -32768         1    -32768    -32768    -32768    -32768    -32768    -32768
    -32768    -32768    -32768    -32768    -32768    -32768    -32768    -32768
  0.1700000E+39  0.2000000E+03  0.3703700E+02 -0.1218830E+03  0.1800000E+02
  0.6900000E+01  0.7100000E+01  0.7000000E+01  0.1700000E+39  0.1700000E+39
  0.3761500E+02 -0.1217450E+03  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.6600000E+02  0.1700000E+39  0.1000000E+05  0.5000000E+02
  0.5000000E+02  0.2564103E+02  0.6000000E+00  0.2000000E+01  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.9790000E+01  0.5366566E+02
  0.9595000E+01 -0.4893999E+02  0.1000000E+00 -0.4000000E+01  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39  0.1700000E+39
|                                                                               
| test 1                                                                        
|                                                                               
 1 cm             1 cm/sec         1 cm/sec/sec                                 
    5   91    0                                                                 
    0.00000E+00    0.20000E-01    0.50000E-01    0.10000E+00    0.20000E+00     
 0.4000E-01 0.4200E-01 0.4400E-01 0.4600E-01 0.4800E-01 0.5000E-01 0.5500E-01   
 0.6000E-01 0.6500E-01 0.7000E-01 0.7500E-01 0.8000E-01 0.8500E-01 0.9000E-01   
 0.9500E-01 0.1000E+00 0.1100E+00 0.1200E+00 0.1300E+00 0.1400E+00 0.1500E+00   
 0.1600E+00 0.1700E+00 0.1800E+00 0.1900E+00 0.2000E+00 0.2200E+00 0.2400E+00   
 0.2600E+00 0.2800E+00 0.3000E+00 0.3200E+00 0.3400E+00 0.3600E+00 0.3800E+00   
 0.4000E+00 0.4200E+00 0.4400E+00 0.4600E+00 0.4800E+00 0.5000E+00 0.5500E+00   
 0.6000E+00 0.6500E+00 0.7000E+00 0.7500E+00 0.8000E+00 0.8500E+00 0.9000E+00   
 0.9500E+00 0.1000E+01 0.1100E+01 0.1200E+01 0.1300E+01 0.1400E+01 0.1500E+01   
 0.1600E+01 0.1700E+01 0.1800E+01 0.1900E+01 0.2000E+01 0.2200E+01 0.2400E+01   
 0.2600E+01 0.2800E+01 0.3000E+01 0.3200E+01 0.3400E+01 0.3600E+01 0.3800E+01   
 0.4000E+01 0.4200E+01 0.4400E+01 0.4600E+01 0.4800E+01 0.5000E+01 0.5500E+01   
 0.6000E+01 0.6500E+01 0.7000E+01 0.7500E+01 0.8000E+01 0.8500E+01 0.9000E+01   
 0.9500E+01 0.1000E+02 0.1100E+02 0.1200E+02 0.1300E+02 0.1400E+02 0.1500E+02   
 Relative Displacement Response Spectrum at 0.00 Damping                        
 0.2377E-02 0.2543E-02 0.3038E-02 0.3575E-02 0.3382E-02 0.4777E-02 0.4314E-02   
 0.5028E-02 0.9993E-02 0.9882E-02 0.1041E-01 0.1224E-01 0.2071E-01 0.3067E-01   
 0.1830E-01 0.3226E-01 0.5011E-01 0.1243E+00 0.1357E+00 0.5743E-01 0.1673E+00   
 0.1294E+00 0.1139E+00 0.1969E+00 0.2241E+00 0.3555E+00 0.2864E+00 0.5695E+00   
 0.1161E+01 0.6391E+00 0.1225E+01 0.1018E+01 0.1362E+01 0.1175E+01 0.1243E+01   
 0.1429E+01 0.2087E+01 0.2259E+01 0.3183E+01 0.2130E+01 0.3379E+01 0.1563E+01   
 0.1672E+01 0.1189E+01 0.2061E+01 0.1423E+01 0.1658E+01 0.1634E+01 0.5186E+01   
 0.1919E+01 0.2479E+01 0.2162E+01 0.4273E+01 0.5399E+01 0.6623E+01 0.3094E+01   
 0.4603E+01 0.4276E+01 0.4322E+01 0.4010E+01 0.6128E+01 0.4934E+01 0.3541E+01   
 0.4295E+01 0.7949E+01 0.1273E+02 0.7865E+01 0.5489E+01 0.6737E+01 0.9248E+01   
 0.1068E+02 0.1119E+02 0.1234E+02 0.1322E+02 0.1390E+02 0.1515E+02 0.2090E+02   
 0.2475E+02 0.2396E+02 0.1871E+02 0.1583E+02 0.1267E+02 0.9982E+01 0.9011E+01   
 0.8630E+01 0.8520E+01 0.8452E+01 0.8081E+01 0.7356E+01 0.6472E+01 0.6243E+01   
 Relative Velocity Response Spectrum at 0.00 Damping                            
 0.1212E+00 0.1499E+00 0.1395E+00 0.1891E+00 0.1830E+00 0.5628E+00 0.1983E+00   
 0.2080E+00 0.4809E+00 0.4814E+00 0.5238E+00 0.6912E+00 0.1158E+01 0.1610E+01   
 0.7739E+00 0.1680E+01 0.2676E+01 0.6422E+01 0.6380E+01 0.2389E+01 0.6634E+01   
 0.4553E+01 0.3653E+01 0.6406E+01 0.6822E+01 0.1103E+02 0.6910E+01 0.1434E+02   
 0.2757E+02 0.1260E+02 0.2560E+02 0.1937E+02 0.2499E+02 0.1990E+02 0.2028E+02   
 0.2198E+02 0.3094E+02 0.3165E+02 0.4298E+02 0.2788E+02 0.4234E+02 0.1787E+02   
 0.1733E+02 0.1036E+02 0.1848E+02 0.1190E+02 0.1379E+02 0.1232E+02 0.3594E+02   
 0.1215E+02 0.1558E+02 0.1220E+02 0.2265E+02 0.2522E+02 0.2873E+02 0.1261E+02   
 0.1742E+02 0.1580E+02 0.1509E+02 0.1335E+02 0.1968E+02 0.1423E+02 0.9526E+01   
 0.9296E+01 0.1855E+02 0.2689E+02 0.1576E+02 0.1024E+02 0.1215E+02 0.1587E+02   
 0.1868E+02 0.1932E+02 0.1876E+02 0.1903E+02 0.1843E+02 0.1802E+02 0.2387E+02   
 0.2704E+02 0.2470E+02 0.2181E+02 0.1470E+02 0.1202E+02 0.1026E+02 0.9182E+01   
 0.8531E+01 0.8050E+01 0.7771E+01 0.7553E+01 0.7239E+01 0.7026E+01 0.6982E+01   
 Pseudo-Velocity Response Spectrum at 0.00 Damping                              
 0.3734E+00 0.3805E+00 0.4338E+00 0.4883E+00 0.4428E+00 0.6003E+00 0.4928E+00   
 0.5266E+00 0.9659E+00 0.8870E+00 0.8721E+00 0.9615E+00 0.1531E+01 0.2141E+01   
 0.1210E+01 0.2027E+01 0.2862E+01 0.6506E+01 0.6561E+01 0.2578E+01 0.7008E+01   
 0.5081E+01 0.4209E+01 0.6874E+01 0.7411E+01 0.1117E+02 0.8181E+01 0.1491E+02   
 0.2806E+02 0.1434E+02 0.2566E+02 0.1999E+02 0.2517E+02 0.2052E+02 0.2054E+02   
 0.2245E+02 0.3123E+02 0.3226E+02 0.4347E+02 0.2788E+02 0.4246E+02 0.1786E+02   
 0.1751E+02 0.1150E+02 0.1850E+02 0.1192E+02 0.1302E+02 0.1208E+02 0.3621E+02   
 0.1269E+02 0.1558E+02 0.1235E+02 0.2237E+02 0.2609E+02 0.2973E+02 0.1296E+02   
 0.1808E+02 0.1580E+02 0.1509E+02 0.1326E+02 0.1925E+02 0.1409E+02 0.9270E+01   
 0.1038E+02 0.1784E+02 0.2666E+02 0.1544E+02 0.1014E+02 0.1176E+02 0.1529E+02   
 0.1677E+02 0.1674E+02 0.1762E+02 0.1806E+02 0.1820E+02 0.1903E+02 0.2387E+02   
 0.2591E+02 0.2316E+02 0.1680E+02 0.1326E+02 0.9948E+01 0.7378E+01 0.6291E+01   
 0.5708E+01 0.5353E+01 0.4828E+01 0.4231E+01 0.3555E+01 0.2905E+01 0.2615E+01   
 Absolute Acceleration Response Spectrum at 0.00 Damping                        
 0.586592E+02 0.569191E+02 0.619419E+02 0.667019E+02 0.579564E+02 0.754375E+02  
 0.562953E+02 0.551417E+02 0.933705E+02 0.796204E+02 0.730636E+02 0.755151E+02  
 0.113180E+03 0.149468E+03 0.800518E+02 0.127345E+03 0.163497E+03 0.340677E+03  
 0.317104E+03 0.115684E+03 0.293558E+03 0.199548E+03 0.155571E+03 0.239955E+03  
 0.245069E+03 0.350862E+03 0.233638E+03 0.390300E+03 0.678083E+03 0.321824E+03  
 0.537479E+03 0.392569E+03 0.465161E+03 0.358056E+03 0.339700E+03 0.352583E+03  
 0.467172E+03 0.460627E+03 0.593806E+03 0.364929E+03 0.533611E+03 0.204018E+03  
 0.183377E+03 0.111121E+03 0.166061E+03 0.998630E+02 0.102268E+03 0.892970E+02  
 0.252773E+03 0.839396E+02 0.978758E+02 0.705356E+02 0.117139E+03 0.126110E+03  
 0.133409E+03 0.542793E+02 0.709874E+02 0.584107E+02 0.526669E+02 0.438574E+02  
 0.604844E+02 0.402444E+02 0.242684E+02 0.250856E+02 0.400264E+02 0.558439E+02  
 0.303220E+02 0.187444E+02 0.205212E+02 0.252825E+02 0.263497E+02 0.250426E+02  
 0.251648E+02 0.246734E+02 0.238196E+02 0.239180E+02 0.272721E+02 0.271371E+02  
 0.223843E+02 0.150756E+02 0.111084E+02 0.781279E+01 0.545407E+01 0.439177E+01  
 0.377497E+01 0.336362E+01 0.275777E+01 0.221554E+01 0.171830E+01 0.130361E+01  

 ... The times of maximum respose, if wanted, would be given here. The format
      would be similar to the last 4 sets of 91 values, only the header line for
      each set would have "Times of Maximum Response" inserted at the beginning.
      
 ... Then the last 4 sets of 91 values (or the last 8 sets if times are
      included) would be repeated for damping = 0.02, 0.05, etc.


6.0  Differences between SMC Format, Version 1 and Version 2
============================================================

- Version 1 time series were all evenly sampled.Version 2 uncorrected (volume 
  1) time series can be given either as unevenly-sampled (x,y) pairs of values 
  or as evenly sampled y-values.  The sampling rate in the real header (header 
  cell #2) will be "undefined" when the time series is unevenly sampled.  

- Version 2 allows for corrected (volume 2) time series.  As a consequence, 
  the meaning of the contents of real header cells 33-36 has been expanded.  
  These four numbers indicate *suggested* filter parameters in files 
  containing uncorrected (volume 1) time series, just as they did in version 1 
  files.  But they indicate the filter parameters that were *actually* used 
  in files containing corrected time series (volume 2) or response spectra 
  (volume 3 data).

- Version 2 allows for files that contain response spectra (volume 3 data) in 
  addition to time-series files.  See section 5. 

- The first line of version 1 files contained nothing but an asterisk (*) in 
  the first column.  The first line of version 2 files contains one of the 
  following:
          1 UNCORRECTED ACCELEROGRAM
          2 CORRECTED ACCELEROGRAM
          3 VELOCITY
          4 DISPLACEMENT
          5 RESPONSE SPECTRA
          6 FOURIER AMPLITUDE SPECTRA OF CORRECTED ACCELERATION

- The third line of an SMC-format file contains the recording station code.  
  This was true in version 1 files too, but BAP version 1 ignored it.  
  
- Version 2 SMC files contain the station number in integer header cell #30.

- The SMC (version 2) files output from BAP (version greater than 1) can now 
  contain the leading and trailing pads which contain filter transients.  
  These are indicated in integer header cells #31 and #32, which contain the 
  number of the first and last recorded sample, respectively, if padding is 
  included in the time series and which contain "undefined" if pads are not
  included.

- Real header cells 27 and 28 are not used in version 2 (*** even in uncorrected
  time series files? ***).  These cells contained suggested filter corner 
  frequencies in version 1 DDS#7 files. 


7.0  File naming conventions
============================

7.1  BAP output file names
==========================

     SMC format files produced by the BAP program have names that are assigned 
by the program, AAVEL.SMC and AARESPON.SMC for example.  The suffix of a 
BAP-assigned file name is either ".SMC" or ".BBF" allow users to determine 
which format the file is in. The user can, of course, rename the files to 
anything they like.  

7.2  DDS#7 file names
=====================
     
     SMC format files on the USGS Digital Data Series DDS-7 CD-ROM, Digitized 
Strong-Motion Accelerograms of North and Central American Earthquakes 1933-1986,
by Linda C. Seekins, A. Gerald Brady, Catherine Carpenter, and Nicholas Brown, 
1992, SMC format files on the DDS#7 CD-ROM have names that are intended to help 
the user determine the contents of the files. Because file names are limited 
to 12 characters on PCs, we came up with the following somewhat-unwieldy 
convention.  The files from each year are stored in a separate directory 
(named by year). Characters 1-3 are the day of the year (001-366); character 
4 is a letter corresponding to the hour (A=0,...X=23); characters 5-6 are the
minutes; characters 7-11, are the four-character station name, unfortunately 
split by a period in character 9; and character 12 is the component code. For
example, a recording of the third component of station STNA from an earthquake 
occurring on July 20 (Julian Day 201), 1979 at 10:22 UTC would be in the 
directory 1979 in a file called 201K22ST.NAC.

     The four-character station codes embedded in DDS#7 file names were taken, 
wherever possible, from Switzer and others (1981) or from the agency which 
provided the records.  Generally they are only three characters long, in which
case the fourth character is a zero.  When two earthquakes occurred within the 
same minute, we used 1 as the fourth character. For some records, no station 
code was listed in the literature; in this case, we made up a four character 
code with X as the first character, although not all station codes beginning 
with X are our invention.
                  

8.0  BAP Software
=================

BAP version 1.1 software for IBM-style PCs that will correct NSMP time series 
is available via the NSMP WWW site at the URL: 
"http://nsmp.wr.usgs.gov/processing.html" and the NSMP anonymous FTP   
server "ftp://smftp.wr.usgs.gov" in the directory at
"/software/bap/4pc/."

The same files are also available from the USGS at the following address:

          USGS Information Services
          Box 25286
          Denver Federal Center
          Denver, Colorado, 80225-0046

          Telephone: (303) 202-4200 or 1-888-ASK-USGS (1-888-275-8747)    
          Fax: (303) 202-4695                                             
          email: infoservices@usgs.gov                                    
          http://mapping.usgs.gov/esic/to_order.html                      

To order the software, request USGS Open-File Report #92-296A, titled "BAP:  
Basic Strong-Motion Accelerogram Processing Software; Version 1.0" for the 
printed user's manual and USGS Open-File Report #92-296B, titled "BAP version 
1.1 software distribution diskettes" for two 1.44 MByte PC diskettes. (Note 
that the printed user's manual is for version 1.0, the diskettes for 
version 1.1.  Differences between the two versions are explained in the 
WHATS.NEW file given on the diskettes. The price for the user's manual is 
$25.25 for paper copy or $4.00 for microfiche; the price for the diskettes is 
$20 (prices as of April 1998). A $5.00 shipping and handling fee is 
applied to all orders (fee as of November 1999).  
                                                                          
     Note that BAP version 1.0 can *not* read the SMC version 2 time-series 
files, but BAP version 1.1 can.

9.0  Update History
===================

     Recent updates or modifications to the SMC-format are listed here.  All
changes are backwards compatible with older versions of the BAP processing
software.

- New sensor code 125 (= Kinemetrics FBA-23) under Integer Headers, cell #15
 (defined November 1, 1999).

- Definition of clock source under Integer Headers, cell #48 (defined
 November 10, 1999).

- New data source definition"6 FOURIER AMPLITUDE SPECTRA OF CORRECTED
ACCELERATION" under Text Headers, line 1 (defined December 3, 1999).

- New sensor code 126 (= Kinemetrics Episensor) under Integer Headers, cell #15 
 (defined January 27, 2000).

- New definitions for previously undefined Real Headers, cells 38 and 39 
 (defined February 11, 2000).

- Integer Header, cells #40-41 are reserved for user now rather than undefined 
 (reserved as of February 07, 2001).

- New sensor codes 127-141 under Integer Headers, cell #15 
 (defined March 9, 2001).

- New sensor code 32 (= Kinemetrics FBA-22, 2-component FBA) under Integer
  Headers, cell #15 (defined August 28, 2001). 

- Integer Header, cell 40 is now reserved for "Vs30 in m/s" (definded April 22, 2008).

- New sensor code 1302 (= Reftek Model 130-ANSS/02) under Integer Headers, cell #15
  (definded January 1, 2009).



10.0  Technical Support
======================

Questions regarding the SMC- or BBF- formats should be directed to:

Kent Fogleman:  (650) 329-4745, fogleman@usgs.gov
    or
Chris Stephens: (650) 329-4752, cdstephens@usgs.gov

U.S. Geological Survey, MS 977
345 Middlefield Road
Menlo Park, CA 94025