StongmotionII Format

Each TYPE_STRONGMOTIONII message is intended to contain information for one
channel only, with optional event association information.

Field units with multiple channels will produce multiple TYPE_STRONGMOTIONII
messages. 

All measurements in the Earthworm TYPE_STRONGMOTIONII message are assumed to be
positive. Any other negative value will result in unpredictable behavior from
strong motion applications. If you have sources that may produce signed values
for PGA, PGV, PGD, or RSA values, you must be sure to change these to absolute
values before they are put into this message.

Message format: everything in quotes is present verbatim in the message. Other
fields are described below. Unless otherwise shown, fields are separated by
spaces. Lines are separated by ASCII newline characters.

"SNCL:" sta.comp.net.loc
"TIME:" date-time
"ALT:" alternate date-time "CODE:" altcode
"PGA:" pga "TPGA:" tpga
"PGV:" pgv "TPGV:" tpgv
"PGD:" pgd "TPGD:" tpdg
"RSA:" nrsa"/"pdrsa rsa"/"pdrsa rsa...
"QID:" qid qauthor

All lines and fields must be present. Null values are described for applicable
fields.


sta.comp.net.loc: Station, component, network, and location codes with `.'
between adjacent fields. Fields may be any length between 1 and (6, 8, 8, 2)
characters in length, respectively. Use `-' if no value is used for the
location code.


date-time: time in the format yyyy/mm/dd hh:mm:ss.sss (year, month, day, hour,
minute, seconds to thousandths. This time is the main timestamp for the
message. If the message came from an SM box in the field, then this is the
trigger time reported by the box. If the message came from a module processing
continuous telemetry, then this is the pick time or earliest of PGA, PGV, or
PGD time. If no value is available for this or any other time, fill the field
with the null date-time "0000/00/00 00:00:00.000".


alternate date-time: same format as above. This is the optional alternate
timestamp for the message. This field is provided as a sanity check or
correction of the main timestamp(t). This timestamp could be assigned by an
acquisition module, database loader, human, or other. The author type of this
timestamp is determined by altcode (see below).


altcode: Required if alternate date-time is specified. Code specifying the
source of the alternate date-time field. Possible values:
 Value:         Description:
   0           Code for no alternate time.
   1           Code for an alternate time derived by a program module that
                  receives a message from a box in the field. 
   2           Code for an alternate time derived by the database or strong
                  motion database insertion module. 
   3           Code for an alternate time derived by a Human (who has
                  hopefully reviewed the data). 


pga: The Peak Ground Acceleration(PGA) for this message. (cm/s/s)
tpga: Time of the pga, yyyy/mm/dd hh:mm:ss.sss
pgv: The Peak Ground Velocity(PGV) for this message. (cm/s)
tpgv: Time of the pgv, yyyy/mm/dd hh:mm:ss.sss
pgd: The Peak Ground Displacement(PGD) for this message. (cm)
tpgd: Time of the pgd, yyyy/mm/dd hh:mm:ss.sss


Any values not available for pga, pgv, and pgd should be assigned -1.0, the
null value.


nrsa: Number of response spectral acceleration (RSA) pairs. Valid value range
      is 0 - 20 
pdrsa rsa: space-separated pair where pdrsa is the period at which RSA values
           are given; rsa is the response spectral acceleration (cm/s/s). Each
      pair of values is preceed by the "/" character. All the values must
      appear on one line.