# 5.8. mag_calc

Functions to calculate local magnitudes automatically, and to calcualte relative moments for near-repeating earthquakes using singular-value decomposition techniques.

copyright: | EQcorrscan developers.
license: | GNU Lesser General Public License, Version 3 (https://www.gnu.org/copyleft/lesser.html)

## 5.8.1. Classes & Functions

`amp_pick_event` | Pick amplitudes for local magnitude for a single event.
`amp_pick_sfile` | Function to pick amplitudes for local magnitudes from NORDIC s-files.
`calc_b_value` | Calculate the b-value for a range of completeness magnitudes.
`calc_max_curv` | Calculate the magnitude of completeness using the maximum curvature method.
`dist_calc` | Function to calculate the distance in km between two points.
`pick_db` | Wrapper to loop through a SEISAN database and make a lot of magnitude picks.
`svd_moments` | Calculate relative moments/amplitudes using singular-value decomposition.

## 5.8.2. Private Functions

Note that these functions are not designed for public use and may change at any point.

`_sim_WA` | Remove the instrument response from a trace and simulate a Wood-Anderson.
`_pairwise` | Wrapper on itertools for SVD_magnitude.
`_max_p2t` | Finds the maximum peak-to-trough amplitude and period.
`_find_resp` | Helper function to find the response information.
`_GSE2_PAZ_read` | Read the instrument response information from a GSE Poles and Zeros file.