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.