UCERF3-ETAS File Formats

Binary Simulation Result, Single Simulation/Catalog

ETAS results are stored in a big-endian binary format for efficiency.

NOTE: most systems/languages assume little-endian byte ordering, so you may need to swap the byte order. Google "big endian" and your programming language if you are unfamiliar. For example, Matlab users will need to use the "swapbytes" function.

The format is as follows:

First a 6-byte header

Data type Name Description
2-byte short int version File format version identifier to accomodate future versions. Currently always '1'
4-byte int num ruptures Total count of rupture records to follow

70-byte rupture records (one for each rupture)

Data type Name Description
4-byte int event ID Unique ID number for the event
4-byte int parent ID ID of the parent for this event, or -1 if spontaneous
2-byte short int generation Generation for this event. 0 means spontaneous
8-byte long origin time Origin time in epoch milliseconds: time since 1/1/1970 GMT
8-byte double latitude Hypocenter latitude in degrees
8-byte double longitude Hypocenter longitude in degrees
8-byte double depth Hypocenter depth in km
8-byte double mag Magnitude
8-byte double dist to parent Distance to parent event, or NaN if spontaneous
4-byte int nth ERF index Internal index for UCERF3-ETAS ERF
4-byte int FSS index Index of UCERF3 Fault System Solution rupture, or -1 if gridded event
4-byte int grid node index Grid node index for Fault System Solution gridded ruptures

Binary Simulation Results, Multiple Simulations/Catalogs

The format for multiple simulations is the same, except it starts with a single integer:

Data type Name Description
4-byte int num catalogs Number of simulations/catalogs present in this file

It is then followed by the "Single Simulation/Catalog" format for each catalog.