TRAVELTIME

1. TRAVELTIME [MORE] [MODEL [string] ] [DEPTH depth] [BB fnum vname] [PICKS [n] ] [PHASE phaselist]

2. TRAVELTIME [MORE] [DIR CURRENT|name] [UNITS DEGREES|KM] [HEADER count] [CONTENT string] [PICKS [n] ] filelist

3. TRAVELTIME [DIR CURRENT|name] [PICKS [n] ] TAUP filename

The first syntax runs a model (for now iasp91 is the only available model), the second syntax reads collumn data, and the third syntax reads the output of taup_curve (a traveltime estimator by Philip Crotwell at the University of South Carolina, for details see http://www.seis.sc.edu/software/index.html).

MORE
signifies addition of more phases (syntax 1) or files (syntax 2) to current traveltime curves rather than replacement of the current list with the new one.

MODEL string
to select the model to use to calculate the travel times. Currently iasp91 is the only available model.

DEPTH depth
Depth at which to produce curves (floaing point number)

BB fnum vname
store a time in a blackboard variable. fnum is an integer specifying the filenumber of a file in SAC's memory. The time of the first phase in the phase list for the specified file is stored in the black board variable specified by the string vname. In case of a null value, the blackboard variable will take the value -12345.0

PICKS n
fills the arrival header fields with the appropriate times. n specifies the first arrival field to use. For example, if n is 6, the first phase will be written in T6, the second in T7, the third in T8 and the fourth in T9. In this case, the fifth and subsequent phases will not be written to header fields, but the curves will be displaied with the PLOTRECORDSECTION command if the TTIME option is ON.

PHASE
the rest of the parameter on the command line are a list of phase names

DIR CURRENT | name
set the name of the default subdirectory from which to read either collumn or taup files.

UNITS degrees/kilometers select units of travel time curves. Defaults to kilometers.

HEADER count set number of lines to skip at the beginning of the file of collumn data.

CONTENT string see below.

filelist
define a new list of files of collumn data (or add to old filelist). The maximum number of rows in a file is 500.

TAUP filename
reads the output of taup_curve. filename is the name of a file which is in the format of the output of taup_curve.

This command reads travel-times from file or computes them from a pre-specified model. The resulting travel time curves can be plotted on top of a record section plot using the PLOTRECORDSECTION command. Currently the only model accessible via the model option is the 1991 iaspei model. The second listed syntax (which reads collumn data) take an optional parameter: CONTENT.

The content field is used to determine how to interperet each collumn. Each specific character in the content string represents a data element and the order of these characters mimics the order of the data in each line of the file. The meanings of the allowed characters in the content field are given below:

T = Next collumn is time in seconds (dependent variable).

D = Next collumn is distance (units specified by the UNITS option) (independent variable).

N = Next collumn is time in seconds.

P = Next pair of entries belong to D and T data sets.

R = Next pair of entries belong to T and D data sets.

I = Ignore (skip) this data element.

An optional repetition count may follow any of the above characters. This repetition count is a one or two digit integer and has the same meaning as repeating the content character that number of times. A period (``.'') is an infinite repetition count and means use the last characters meaning to decode the remaining data elements in the line. The period can only appear at the end of a content field.

Note: a given collumn data file can only have one distance collumn read.