Sta/Lta Triggering - Gecko Compact Product User Manual

STA/LTA Triggering

By default the STA/LTA trigger process is OFF. Toggle this ON/OFF using the Right button.
The Short Term Average (STA) signal level divided by the Long Term Average (LTA) signal
level produces a ratio indicating how much above-average signal is occurring.
If you want to declare and event when the short term average signal level is three times
higher than the long term average signal level, you set the Threshold to 3. The length of
the short term and long term time windows is also user selectable.
The LTA value must be larger than the STA value.
Signal averages can be calculated using the raw data or filtered to suit to local earthquake
detection. On the Filter line, use the Right button to toggle the 2-20Hz filter on or off.
The STA/LTA algorithm can run on any, some, or all of the 3D input channels, which you
can cycle through using the Right button on the last menu item.
A more detailed explanation of the STA/LTA trigger algorithm is provided in our Waves data
analysis application's user manual. You can visualise the effect of changing the various
STA/LTA settings using Waves.
STA/LTA Triggering
Enable: Off
> Threshold
STA window size
LTA window size
Filter: 2-20Hz
Channel: Z+N+E
Short Term Average
2.0 second
averaging window
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