https://github.com/miili/pysurf96

Python wrapper for modelling surface wave dispersion curves from surf96 - Computer Programs in Seismology, R. Hermann
https://github.com/miili/pysurf96

dispersion geophysics python seismology surf96

Last synced: 6 days ago
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Python wrapper for modelling surface wave dispersion curves from surf96 - Computer Programs in Seismology, R. Hermann

• Host: GitHub
• URL: https://github.com/miili/pysurf96
• Owner: miili
• Created: 2018-11-21T15:02:04.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2024-12-04T18:29:11.000Z (19 days ago)
• Last Synced: 2024-12-04T18:34:18.078Z (19 days ago)
• Topics: dispersion, geophysics, python, seismology, surf96
• Language: Fortran
• Homepage: https://pyrocko.org
• Size: 44.9 KB
• Stars: 59
• Watchers: 6
• Forks: 21
• Open Issues: 5
• Metadata Files:
  • Readme: README.md

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README

        
# PySurf96

[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)

[![Python 3.10+](https://img.shields.io/badge/Python-3.10+-blue.svg)](https://python.org/)

_Modelling Surface Wave Dispersion Curves_

This is a slim wrapper around the program `surf96` from _Computer programs in seismology_ by R. Hermann () for forward modelling of Rayleigh and Love wave dispersion curves.

In this implementation the Fortran77 code is wrapped by `f2py`, which makes the forward computation approximately **8x faster** compared over calling a Python subprocess.

More useful software for seismology at .

## Installation

This package is for Python 3.

Prerequisits is a Fortran77 compiler, like GNU GCC.

```

pip install .

```

Or through pip:

```

pip install git+https://github.com/miili/pysurf96

```

## Documentation

Essentially this is a single function, `surf96`. Here is the docstring:

```

Calculate synthetic surface wave dispersion curves for a given earth model, wave type and periods.

This is a slim Fortran wrapper around surf96 from Computer Programs in Seismology from R. Hermann (2013)

Args:

    thickness (np.ndarray): Layer thickness in kilometers.

    vp (np.ndarray): Layer Vp velocity.

    vs (np.ndarray): Layer Vs velocity.

    rho (np.ndarray): Layer density in g/m^3.

    periods (np.ndarray): The periods in seconds, where wave velocity is calculated

    wave (WaveType, optional): The wave type, "love" or "rayleigh". Defaults to "love".

    mode (int, optional): Mode of the wave, 1: fundamental, 2: second-mode, etc... Defaults to 1.

    velocity (Velocity, optional): "group" or "phase" velocity. Defaults to "group".

    flat_earth (bool, optional): Assume a flat earth. Defaults to True.

Raises:

    ValueError: Raised when input values are unexpected.

    Surf96Error: If surf96 fortran code raises an error,

        this may be due to low velocity zone.

Returns:

    np.ndarray: The surface wave velocities at defined periods.

```

## Example

```python

import numpy as np

from pysurf96 import surf96

# Define the velocity model in km and km/s

thickness = np.array([5.0, 23.0, 8.0, 0])

vs = np.array([2, 3.6, 3.8, 3.3])

vp = vs * 1.73

rho = vp * 0.32 + 0.77

# Periods we are interested in

periods = np.linspace(1.0, 20.0, 20)

velocities = surf96(

    thickness,

    vp,

    vs,

    rho,

    periods,

    wave="love",

    mode=1,

    velocity="group",

    flat_earth=True,

```

## Citations and Acknowledgments

> Herrmann, R. B. (2013) Computer programs in seismology: An evolving tool for instruction and research, Seism. Res. Lettr. 84, 1081-1088, doi:10.1785/0220110096

Thanks to Hongjian Fang for creating the Fortran subroutine ()