Cheryl noted last night that the seismic system transitioned to earthquake last night without warning. This actually happened twice last night, I think the two attached earthquakes from USGS were the culprits. They were far enough away that we should have gotten some warning (5600 km, the closest seismon will give us early warning for is about 2000 km), but maybe the fact they were out in the middle of the ocean delayed the USGS reports. The later one is still on seismon, and gets a deceptive eq response "score", falling well into the blue region, so a good reminder to be kind of skeptical about what the plot tells you. Still, SEI_ENV caught both earthquakes and transitioned properly, and we stayed locked for both earthquakes.

Second attached plot shows SEI_ENV (in blue) jumping from CALM (index 10) to EARTHQUAKE (index 20), as both earthquakes cross 1000 nm/s on peakmon (in yellow). SEI_CONF (green) goes from WINDY to EARTH_QUAKE both times, in the IFO stayed locked for both earthquakes. It's possible that we could have ridden both of these earthquakes out without doing anything, but these earthquakes were both on the top end of the kind of earthquakes we were able to ride out for O2 before we had an actual earthquake control scheme. Both of these earthquakes would have been a challenge for a person to first realize what was happening, then make the decision to switch the seismic system before the earthquakes had come and gone.