(sec-file-formats-TimeHistoryDB)=
# TimeHistoryDB Format

`TimeHistoryDB` database files contain a header describing the number of points in the time history and the units for the time stamps followed by a list with pairs of time stamps and amplitude values.

```{code-block} c++
// This time history database specifies temporal variation in
// amplitude. In this case we prescribe a triangular slip time
// history. 
//
// Comments can appear almost anywhere in these files and are
// delimited with two slashes (//) just like in C++. All text and 
// whitespace after the delimiter on a given line is ignored.
//
// The next line is the magic header for spatial database files 
// in ASCII format.
#TIME HISTORY ascii
TimeHistory { // start specifying the database parameters
  num-points = 5 // number of points in time history

  // Specify the units used in the time stamps.
  time-units = year
} // end of TimeHistory header
// The time history values are listed after the parameters.
// Columns time and amplitude where the amplitude values are unitless.
 0.0     0.00
 2.0     1.00
 6.0     4.00
10.0     2.00
11.0     0.00
```