Earthworms sense these changes coming and evacuate deeper soils in anticipation. This adaptational behaviour is a result of surviving the deaths of countless trillions of earthworms who did not demonstrate this reaction before large quakes.
I heard it's a real phenomenon on the West Coast, in addition to the marine life beachings which are now becoming epidemic.
There are very big quakes coming. The Japanese quake was a mere simmering in comparison.