ps2ff

Produce approximated finite fault distances and variance corrections given point source information, for example Repi (epcentral distance) to Rjb (Joyner-Boore distance) or Rrup (closest distance to rupture).

Using the results (the API)

The command line programs (described below) can be used to generate new distance adjustments. This package also includes a set of correction factors for some common conditions (e.g., typical active crustal regions). These can most easily be used with the interpolate module that contains the PS2FF class, which enables the use of the tables for arbitrary magnitudes and epicentral distance values. See the ps2ff.interpolate section of this package's documentation.

Prerequisites and Installation

These programs run in Python 3.5 or later, and require a number of packages, including the conda package manager. The dependency list is given in install.sh. The easiest way to install this code is to run install.sh in OSX or Linux. It will install miniconda (if a version of conda is not already installed) and then all the dependencies in a virtual environment named ps2ff. To use this environment after installation, type

source activate ps2ff

Background

This code implements the methods descibed by:

• Thompson, E. M., and C. B. Worden (2017). Estimating rupture distances without a rupture, Bulletin of the Seismological Society of America. DOI: https://doi.org/10.1785/0120170174.

Running the Programs

The primary program is run_ps2ff, which must be given a configuraiton file

ps2ff -w Rjb config_file.ini

where '-w Rjb' is the 'what' command line argument. There are example configuration files in the ps2ff/config directory.

Output Tables

The ps2ff/tables directory contains example results for some generic seismological assumptions. The output file name convension is easiest to describe with an example:

Rjb_S14_mechA_ar1p0_seis0_15_Ratios.csv

where:

• "Rjb" is the the what command line argument.
• "S14" is the selected rup_dim_model.
• "mechA" specifies the rupture mechanism parameter mech, where "A" can be one of "A", "SS", "N", or "R".
• "ar1p0" is the aspect ratio specified with the AR parameter, where the decimal point is replaced with the letter 'p'.
• "seis0_15" is the range min/max seismogenic depths (in this case 0 to 15 km).
• "Ratios" is either "Ratios" or "Var" specifying whether the file contains Rjb- or Rrup-to-Repi ratios, or variances.

Each output table starts with six header lines (each beginning with #) specifying the processing parameters. This is followed by a line (comma-separated) providing the column headers. The first column, "Repi_km", is the epicentral distance. The following columns "R(magnitude)" ("R" for "ratio") or "V(magnitude)" ("V" for "variance) provide the values for a given Repi and magnitude. The table is intended for bi-variate interpolation, linear in magnitude and logarithmic in distance. The ratios are Rjb (or Rrup) to Repi.

Program Details

run_ps2ff produces tables of Rjb-to-Repi or Rrup-to-Repi ratios and variances. Example configuration files may be found in ps2ff/config.

run_ps2ff_single_event produces tables of Rrup-to-Repi and Rjb-to-Repi ratios and variances for a single event. This means that the magnitdue and hypocentral depth are available, simplifying the integration. It optionally tabulates the adjustment factors as a function of backazimuth. An example configuration file for this program is given in tests/config/test_single.ini.

See this package's documentation on the command line interface for more on usage and configuration options.