LASIF (Larg-scale Seismic Inversion Framework) is a data-driven workflow tool to perform full waveform inversions. It is opinionated and strict, meaning that it enforces a certain data and directory structure. The advantage is that it only requires a very minimal amount of configuration and maintenance. It attempts to gather all necessary information from the data itself so there is no need to keep index or content files.
All parts of LASIF also work completely on their own; see the class and function documentation at the end of this document. Furthermore LASIF offers a project based inversion workflow management system which is introduced in the following tutorial.
LASIF works with the notion of so called inversion projects. A project is defined as a series of iterations working on the same physical domain. Where possible and useful, LASIF will use XML files to store information. The reasoning behind this is twofold. It is easily machine and human readable. It furthermore also serves as a preparatory step towards a fully database driven full waveform inversion workflow as all necessary information is already stored in an easily indexable data format.
LASIF is data-driven, meaning that it attempts to gather all necessary information from the available data. The big advantage of this approach is that the users can use any tool they want to access and work with the data as long as they adhere to the directory structure imposed by LASIF. At the start of every LASIF operation, the tool checks what data is available and uses it. To achieve reasonable performance it employs a transparent caching scheme able to quickly any changes the user makes to the data. Also important to keep in mind is that LASIF will never delete any data.
The aim of the LASIF project is to facilitate the execution of mid-to large-scale full seismic waveform inversion using adjoint techniques. A simplified representation of the general workflow is presented here.
One of the biggest problems is the meaningful organization of the different types of data which are mostly in non-trivial relations to each other.
LASIF attempts to tackle these issues by employing a number of modules tied together by a common project.
The documentation is currently being restructured. For now additional information can be found here:
Supported Data Formats¶
This is a short list of supported data formats and other software.
- Waveform Data: All file formats supported by ObsPy.
- Synthetics: All file formats supported by ObsPy and the output files of SES3D 4.1.
- Event Metadata: QuakeML 1.2
- Station Metadata: dataless SEED, RESP and FDSN StationXML. We strongly recommend to use StationXML!
- Earth Models: Currently the raw SES3D model format is supported. Other solvers can still be used but LASIF will not be able to plot kernels and velocity models.
- Waveform Solvers: SES3D 4.1, SPECFEM3D GLOBE
LASIF is designed to work with valid QuakeML 1.2 event files. Please assure that the files you use actually are just that. If possible try to only use QuakeML files with one origin and one focal mechanism, otherwise LASIF will choose the preferred origin and/or focal mechanism (or the first of each, if no preferred one is specified). The origin time specified in the QuakeML file will be the reference time for each event! Times specified in SAC files will be ignored.
This also means that the raw data files have to have the correct time information.