3.1. quakemigrate.core

The quakemigrate.core module provides Python bindings for the library of compiled C routines that form the core of QuakeMigrate:

  • Migrate onsets - This routine performs the continuous migration through time and space of the onset functions. It has been parallelised with openMP.
  • Find maximum coalescence - This routine finds the continuous maximum coalescence amplitude in the 4-D coalesence volume.
copyright:2020, QuakeMigrate developers.
license:GNU General Public License, Version 3 (https://www.gnu.org/licenses/gpl-3.0.html)

3.1.1. Functions

Bindings for the C library functions, migrate and find_max_coa.

copyright:2020, QuakeMigrate developers.
license:GNU General Public License, Version 3 (https://www.gnu.org/licenses/gpl-3.0.html)
quakemigrate.core.lib.find_max_coa(map4d, threads)[source]

Finds time series of the maximum coalescence/normalised coalescence in the 3-D volume, and the corresponding grid indices.

Parameters:
  • map4d (numpy.ndarray of numpy.double) – 4-D coalescence map, shape(nx, ny, nz, nsamples).
  • threads (int) – Number of threads with which to perform the scan.
Returns:

  • max_coa (numpy.ndarray of numpy.double) – Time series of the maximum coalescence value in the 3-D volume.
  • max_norm_coa (numpy.ndarray of numpy.double) – Times series of the maximum normalised coalescence value in the 3-D volume.
  • max_coa_idx (numpy.ndarray of int) – Time series of the flattened grid indices corresponding to the maximum coalescence value in the 3-D volume.

quakemigrate.core.lib.migrate(onsets, traveltimes, first_idx, last_idx, available, threads)[source]

Computes 4-D coalescence map by migrating seismic phase onset functions.

Parameters:
  • onsets (numpy.ndarry of float) – Onset functions for each seismic phase, shape(nstations, nsamples).
  • traveltimes (numpy.ndarry of int) – Grids of seismic phase traveltimes converted to an integer multiple of the sampling rate, shape(nx, ny, nz, nstations).
  • first_idx (int) – Index of first sample in array from which to scan.
  • last_idx (int) – Index of last sample in array up to which to scan.
  • available (int) – Number of available onset functions.
  • threads (int) – Number of threads with which to perform the scan.
Returns:

map4d – 4-D coalescence map, shape(nx, ny, nz, nsamples).

Return type:

numpy.ndarray of numpy.double

Raises:
  • ValueError – If mismatch between number of onset functions and traveltime lookup tables - expect both to be equal to the no. stations * no. phases.
  • ValueError – If the number of samples in the onset functions is less than the number of samples array is smaller than map4d[0, 0, 0, :].