Noisi - ambient noise cross-correlation modeling and inversion

This tool can be used to simulate noise cross-correlations and sensitivity kernels to noise sources.

Installation requirements

Install requirements (easiest done with anaconda)

• obspy
• PyYaml
• pandas
• mpi4py
• proj
• geos
• geographiclib
• cartopy
• h5py
• jupyter
• pytest
• pyasdf
• psutil

Additionally, install instaseis, if you plan to use it for Green's functions (conda install instaseis). If there are issues installing instaseis with conda, cloning the github repository and installing that usually works: https://github.com/sstaehler/instaseis.

Install jupyter notebook if you intend to run the tutorial (see below).

If you encounter problems with mpi4py, try removing it and reinstalling it using pip (pip install mpi4py).

Installation step-by-step

Clone the repository with git:
git clone https://github.com/jigel/noisi_inv.git

Create a new environment and activate it:
conda create -n noisi_inv python=3.8
conda activate noisi_inv

Install a few necessary packages:
conda install proj geos shapely mpi4py h5py instaseis --yes

Install noisi_inv (in the noisi_inv directory) which should install all other packages. Change into the noisi_inv/ directory. Call pip install . here, or call pip install -v -e . if you intend to modify the code.

After installation, change to the noisi_inv/noisi directory and run pytest. If you encounter any errors (warnings are o.k.), we'll be grateful if you let us know.

Getting started

Noisi_inv is slightly different to noisi as it includes a complete inversion workflow. This is all setup in the run_inversion.py file. To do a little test inversion and check if it was installed correctly you can run the following command:
python run_inversion.py inversion_config.yml

To see an overview of the tool, type noisi --help. A step-by-step tutorial for jupyter notebook can be found in the noisi_inv/noisi directory. Examples on how to set up an inversion and how to import a wavefield from axisem3d are found in the noisi/examples directory.

Tutorial: Inversion setup

We have added a jupyter notebook to help you setup a config file for an inversion. All the different parameters are explained within that notebook. It is also available as python script.

It is recommended to download a pre-computed wavefield if you want to do proper inversions (http://ds.iris.edu/ds/products/syngine/). These are then easily implemented in the config file.

Documentation

You can find more information about the code and the parameters for the inversion in the noisi_inv_doc.pdf. This package is a mix of various different codes to allow the automatic downloading, processing, correlating, and inverting of seismic ambient noise data.