pyacs.lib.faultslip package

Submodules

pyacs.lib.faultslip.fault_to_corners module

pyacs.lib.faultslip.fault_to_corners.fault_to_corners(lon, lat, depth, length, width, strike, dip)[source]
Parameters
  • lon – origin longitude for fault

  • lat – origin latitude for fault

  • length – fault length in km

  • width – fault width in km

  • strike – fault strike in degrees

  • dip – fault dip in degrees

Returns

lonc, latc, depthc 1D numpy arrays of the 4 fault corners

Note

use a flat Earth approximation, depth is negative

pyacs.lib.faultslip.geo_to_strike module

pyacs.lib.faultslip.geo_to_strike.geo_to_strike(ilon, ilat, elon, elat)[source]

for a given fault segment starting at ilon,lat and ending at elon, elat , returns the strike.

Parameters
  • ilon,ilat – geographical coordinates of fault segment start point in decimal degrees

  • elon,elat – geographical coordinates of fault segment end point in decimal degrees

Returns strike

in decimal degrees clockwise from north

Note

strike here is taken as the initial bearing. Be cautious with long segments

pyacs.lib.faultslip.rake_from_euler module

pyacs.lib.faultslip.rake_from_euler.rake_from_euler(longitude, latitude, strike, dip, euler)[source]

predicts rake for a given fault according to an Euler pole, position and strike of the fault

Parameters
  • longitude,latitude – in decimal degrees

  • strike – fault strike from north in decimal degrees

  • dip – fault dip from north in decimal degrees

  • euler – Euler pole as a string ‘/long/lat/w/style’ (style among ‘inverse’, ‘normal’, ‘leftlateral’,’rightlateral’)

Return rake

in decimal degrees

Note

style needs to be provided to ensure the correct sense of slip.

pyacs.lib.faultslip.slip_rake_2_ds_ss module

pyacs.lib.faultslip.slip_rake_2_ds_ss.slip_rake_2_ds_ss(slip, rake)[source]

Converts a slip vector provided as slip and rake to dip slip and strike-slip components

Parameters
  • slip – slip

  • rake – rake in degrees

:return ( slip*np.sin( np.radians(rake) ) , slip*np.cos( np.radians(rake) ))

Note

ds will be positive for rake in [0,180] that is reverse motion ss will be positive for left-lateral motion

pyacs.lib.faultslip.ss_ns_2_ve_vn module

pyacs.lib.faultslip.ss_ns_2_ve_vn.ss_ns_2_ve_vn(ss, ns, strike)[source]

Converts strike-slip and normal slip components of a fault to ve, vn

Parameters
  • ss – vector of strike-slip

  • ns – vector of normal-slip

  • strike – vector of fault strike, counter-clockwise from north in degrees

Returns

ve, vn, same unit as ss and ds

Note

ss is assume to be positive for left-lateral motion ds will be positive for reverse motion

pyacs.lib.faultslip.strike_dip_rake_to_dir module

pyacs.lib.faultslip.strike_dip_rake_to_dir.strike_dip_rake_to_dir(strike, dip, rake)[source]

for a given (strike,dip,rake) returns the azimuth of the horizontal motion :param strike,dip,rake: in decimal degrees :returns: direction: slip direction (modulo 180 degrees)

pyacs.lib.faultslip.v_to_n_ss module

pyacs.lib.faultslip.v_to_n_ss.v_to_n_ss(ve, vn, strike)[source]

for a given relative horizontal velocity (ve,vn) between two blocks separated by a fault of a given strike , returns normal and strike-slip component of motion. The convention is that the point is in the left-domain with respect to the fault. Shortening & right-lateral are positive, extension and left-lateral negative

Parameters
  • ve,vn – east and north components of motion (any unit)

  • strike – in decimal degrees

Returns normal,strike-slip

same units as ve,vn

pyacs.lib.faultslip.v_to_rake module

pyacs.lib.faultslip.v_to_rake.v_to_rake(ve, vn, strike, dip, style='inverse')[source]

for a given relative horizontal velocity (ve,vn) between two blocks separated by a fault of a given strike & dip , returns the expected rake for the eq.

Parameters
  • ve,vn – east and north components of motion (any unit)

  • strike,dip – in decimal degrees

  • style – string among {‘inverse’, ‘normal’, ‘leftlateral’,’rightlateral’}

Returns rake

in decimal degrees

Note

Because only providing ve,vn is ambiguous (we don’t know whether if ve,vn is hanging wall motion wrt the footwall or the opposite) an additional information (style) in the form of one of {‘inverse’, ‘normal’, ‘leftlateral’,’rightlateral’} must be provided.

Module contents

Various routines relating fault parameters, slip and motion across faults