NCEDC Daily Catalog Snapshots

Information about earthquakes is updated over time, as we review and reprocess the data used to locate them and determine their magnitudes. To scientifically evaluate and compare seismicity, it is important to be using the same catalog.

The NCEDC is pleased to announce the availability of daily snapshots for the earthquake parameters catalog of the Northern California Seismic System through GitHub. This means that at any time the catalog can be retrieved as it was on a given date. The catalog repository is available at:

The files contain information from 1966 to present and are available in the EHP CSV format. For documentation on the format, please go to:

A current snapshot of these files can also be found at:

In the GitHub repository, which contains snapshots from 2017/04/10 to the present, a file 'index.txt' is provided that contains the mapping between the commit times and the hash keys. It can be used to retrieve a version of the catalog at a given time.

How to use the index file

This file contains entries similar to the following:

NCSS catalogs as of 2023-01-04 01:00:01 --> 5a66d312274f7720e0ce701a15aa6b751ac543d3
NCSS catalogs as of 2023-01-03 01:00:01 --> a58bded32471e324405864d8f85b04f3bb8b31eb
NCSS catalogs as of 2023-01-02 01:00:02 --> e87dc9c209ae156c80c5a09010184eabe3fa25f5
NCSS catalogs as of 2023-01-01 01:00:01 --> c096c72cedcb0ae4621a67749100d12fae96fbf6

For example, a snapshot of the catalog on 2023/01/04 13:00:01 would be available at:

Specific snapshots are available at:<HASH_KEY>