Default Parameters

Each of the tools use Java Properties to allow the user to specify values for various parameters. The properties all have default values, which are overridden by values from a Properties file. The tools use a text file to load the properties. It reads .taup in the current directory, which overwrites values read in from .taup in the user’s home directory. Properties may also be specified by the --prop command line argument. In addition, many of the properties can be overridden by command line arguments.

The form of the properties file is very simple. Each property is set using the form taup.property.name=value one property per line. Comment lines are allowed, and begin with a #. Additionally, the names of all of the properties follow a convention of prepending taup. to the name of the property. This helps to avoid name collisions when new properties are added.

The currently used properties are:

  • taup.model.name the name of the initial model to be loaded, iasp91 by default.

  • taup.model.path search path for models. There is no default, but the value in the .taup file will be concatinated with any value of taup.model.path from the system properties. For example, the environment variable TAUPPATH is put into the system property taup.model.path by the wrapper shell scripts.

  • taup.source.depth initial depth of the source, 0.0 km by default.

  • taup.phase.list initial phase list, combined with taup.phase.file. The defaults are p, s, P, S, Pn, Sn, PcP, ScS, Pdiff, Sdiff, PKP, SKS, PKiKP, SKiKS, PKIKP, SKIKS.

  • taup.phase.file initial phase list, combined with taup.phase.list. There is no default value, but the default value for taup.phase.list will not be used if there is a taup.phase.file property.

  • taup.depth.precision precision for depth output, the default is 1 decimal digit. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning.

  • taup.distance.precision precision for distance output, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning.

  • taup.latlon.precision precision for latitude and longitude output, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning.

  • taup.time.precision precision for time, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning.

  • taup.rayparam.precision precision for ray parameter, the default is 3 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning.

  • taup.maxRefraction The maximum degrees that a Pn or Sn can refract along the moho. Note this is not the total distance, only the segment along the moho. The default is 20 degrees.

  • taup.maxDiffraction The maximum degrees that a Pdiff or Sdiff can diffract along the CMB. Note this is not the total distance, only the segment along the CMB. The default is 60 degrees.

  • taup.maxKmpsLaps The maximum number of laps around the earth for kpms style phases. Note this is the number of laps, not number of arrivals, so a value of 1 would give 2 arrivals, one going the short path and one the long way around. This can be fractional, so 0.5 would exclude the long way around path. The default is 1.

  • taup.path.maxPathInc maximum distance in degrees between points of a path. This does a simple linear interpolant between nearby values in order to make plots look better. There is noo improvement in the accuracy of the path.

  • taup.table.locsat.maxdiff maximum distance in degrees for which Pdiff or Sdiff are put into a locsat table. Beyond this distance Pdiff and Sdiff will not be added to the table, even though they may show up in the output of TauP Time. Instead, the next later arriving phase, if any, will be used instead. The default is 105 degrees.

  • taup.create.minDeltaP Minimum difference in slowness between successive slowness samples. This is used to decide when to stop adding new samples due to the distance check. Used by TauP Create to create new models. The default is 0.1 sec/rad.

  • taup.create.maxDeltaP Maximum difference in slowness between successive slowness samples. This is used to split any layers that exceed this slowness gap. Used by TauP Create to create new models. The default is 11.0 sec/rad.

  • taup.create.maxDepthInterval Maximum difference between successive depth samples. This is used immediately after reading in a velocity model, with layers being split as needed. Used by TauP Create to create new models. The default is 115 km.

  • taup.create.maxRangeInterval Maximum difference between successive ranges, in degrees. If the difference in distance for two adjacent rays is greater than this, then a new slowness sample is inserted halfway between the two existing slowness samples. The default is 2.5 degrees.

  • taup.create.maxInterpError Maximum error for linear interpolation between successive sample in seconds. TauP Create uses this to try to insure that the maximum error due to linear interpolation is less than this amount. Of course, this is only an approximation based upon an estimate of the curvature of the travel time curve for surface focus turning waves. In particular, the error for more complicated phases is greater. For instance, if the true error for P at 30 degrees is 0.03 seconds, then the error for PP at 60 degrees would be twice that, 0.06 seconds. Used by TauP Create to create new models. The default is 0.05 seconds.

  • taup.create.allowInnerCoreS Should we allow J phases, S in the inner core? Used by TauP Create to create new models. The default is true. Setting it to false slightly reduces storage and model load time.

Phase files, specified with the taup.phase.file property, are just text files with phase names, separated by either spaces, commas or newlines. In section Phases the details of the phase naming convention are introduced. By and large, it is compatible with traditional seismological naming conventions, with a few additions and exceptions. Also, for compatiblity with ttimes, you may specify ttp, ttp+, tts, tts+, ttbasic or ttall to get a phase list corresponding to the ttimes options.