Changes between Version 3 and Version 4 of eqcoda


Ignore:
Timestamp:
05/28/12 08:00:09 (8 years ago)
Author:
branden
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • eqcoda

    v3 v4  
    170170}}} 
    171171 
    172 !LabelVersion [switch] 
    173 Processed by: eqc_config 
     172'''!LabelVersion [switch]'''[[BR]] 
     173Processed by: eqc_config[[BR]] 
    174174Function: output 
    175175 
     
    268268Function: constants 
    269269 
    270 Gives the name of the stationfile eqcoda must read to set per-channel parameters; see pick_ew's station list format for field descriptions and examples. Eqcoda should read the same station file as pick_ew. Eqcoda uses only five of the fields of the station file: Station, Comp, Net (#3,4,5), CodaTerm (#19), and ClipCount (#23). The Station, Comp, Net fields identify the Station, Component, and Network codes of each channel. The CodaTerm field defines the coda termination level (counts) for each channel. The ClipCount field (added specifically for eqcoda, ignored by pick_ew) specifies the maximum amplitude (counts zero-to-peak) that can be expected for each channel. Eqcoda calculates clipping thresholds for P-amplitudes (KlipP1, KlipP2) and coda-window average absolute amplitudes (KlipC) as a fraction of ClipCount. See Notes on eqcoda's default values for its constants below for details. 
    271  
    272 If the !StaFile command is omitted, eqcoda will use the original global defaults (appropriate for 12-bit Earthworm analog data) for all channels. If a channel is not listed in stationfile, eqcoda will use the default parameters (appropriate for 12-bit Earthworm analog data) for that channel. If a channel is listed in stationfile, but the ClipCount field is missing, eqcoda will use DefaultClipCount=2048 (also appropriate for 12-bit Earthworm analog data) for that channel. On startup, eqcoda logs the parameters it will use for each channel, with an asterisk denoting default values. 
     270Gives the name of the stationfile eqcoda must read to set per-channel parameters; see pick_ew's station list format for field descriptions and examples. Eqcoda should read the same station file as pick_ew. Eqcoda uses only five of the fields of the station file: Station, Comp, Net (#3,4,5), !CodaTerm (#19), and !ClipCount (#23). The Station, Comp, Net fields identify the Station, Component, and Network codes of each channel. The CodaTerm field defines the coda termination level (counts) for each channel. The !ClipCount field (added specifically for eqcoda, ignored by pick_ew) specifies the maximum amplitude (counts zero-to-peak) that can be expected for each channel. Eqcoda calculates clipping thresholds for P-amplitudes (KlipP1, KlipP2) and coda-window average absolute amplitudes (KlipC) as a fraction of !ClipCount. See Notes on eqcoda's default values for its constants below for details. 
     271 
     272If the !StaFile command is omitted, eqcoda will use the original global defaults (appropriate for 12-bit Earthworm analog data) for all channels. If a channel is not listed in stationfile, eqcoda will use the default parameters (appropriate for 12-bit Earthworm analog data) for that channel. If a channel is listed in stationfile, but the !ClipCount field is missing, eqcoda will use DefaultClipCount=2048 (also appropriate for 12-bit Earthworm analog data) for that channel. On startup, eqcoda logs the parameters it will use for each channel, with an asterisk denoting default values. 
    273273 
    274274Pick_ew reports the first three peaks of the P-wave arrival. Eqcoda computes the average for its output message. If the first (of 3) P-amplitude exceeds KlipP1 counts, eqcoda considers it to be clipped. If the second or third P-amplitude exceed KlipP2, they are considered to be clipped. Eqcoda excludes any clipped values when calculating the average P-amplitude. 
    275275 
    276 Pick_ew reports coda duration as the time from the P-arrival to the time when the average absolute amplitude of a 2-second trace data window reaches CodaTerm counts. Pick_ew also reports the average absolute amplitudes of up to six 2-second coda windows. Eqcoda finds the slope of the coda decay by performing an L1 fit to the coda amplitudes, ignoring any coda amplitudes that precede the predicted S-wave arrival or that exceed that channel's coda clipping (KlipC) threshold. Eqcoda extrapolates the coda decay to a level of CodaTerm counts, estimating the coda duration for those picks that pick_ew has timed-out on (pick_ew waits a maximum of 144 seconds for the coda to reach the CodaTerm value). 
     276Pick_ew reports coda duration as the time from the P-arrival to the time when the average absolute amplitude of a 2-second trace data window reaches CodaTerm counts. Pick_ew also reports the average absolute amplitudes of up to six 2-second coda windows. Eqcoda finds the slope of the coda decay by performing an L1 fit to the coda amplitudes, ignoring any coda amplitudes that precede the predicted S-wave arrival or that exceed that channel's coda clipping (KlipC) threshold. Eqcoda extrapolates the coda decay to a level of !CodaTerm counts, estimating the coda duration for those picks that pick_ew has timed-out on (pick_ew waits a maximum of 144 seconds for the coda to reach the !CodaTerm value). 
    277277 
    278278For extrapolated coda lengths to be consistent with "normally-terminating" (<144 sec) coda lengths reported by pick_ew, be sure that both modules read the same station file. 
     
    303303    KlipP2 = 1148 count 
    304304}}} 
    305 Originally, eqcoda used a set of global constants for all channels because all data in the system was produced by the Earthworm digitizer. In Earthworm versions v5.1 and higher, eqcoda can be configured to use per-channel constants instead of the original global constants. To set per-channel constants, eqcoda must read a station list file, the same file that is read by pick_ew. Eqcoda uses 5 fields: station, component, network, CodaTerm, and ClipCount. The ClipCount field (added specifically for eqcoda, ignored by pick_ew) specifies the maximum amplitude (counts zero-to-peak) that can be expected for each channel. Eqcoda calculates each channel's three clipping constants by multiplying its ClipCount by the fractions used in the original definitions (see above). If the ClipCount field is omitted from the station file, eqcoda assumes the channel is a standard Earthworm analog channel from a 12-bit digitizer and it assigns a DefaultClipCount = 2048. 
     305Originally, eqcoda used a set of global constants for all channels because all data in the system was produced by the Earthworm digitizer. In Earthworm versions v5.1 and higher, eqcoda can be configured to use per-channel constants instead of the original global constants. To set per-channel constants, eqcoda must read a station list file, the same file that is read by pick_ew. Eqcoda uses 5 fields: station, component, network, CodaTerm, and ClipCount. The !ClipCount field (added specifically for eqcoda, ignored by pick_ew) specifies the maximum amplitude (counts zero-to-peak) that can be expected for each channel. Eqcoda calculates each channel's three clipping constants by multiplying its !ClipCount by the fractions used in the original definitions (see above). If the !ClipCount field is omitted from the station file, eqcoda assumes the channel is a standard Earthworm analog channel from a 12-bit digitizer and it assigns a !DefaultClipCount = 2048. 
    306306 
    307307== Helpful Hints ==