The Earth Moves - but not for Pat!

I woke up in the night to a weird experience - it seemed as though I was in the middle of a whirlwind everything rushing around me in a blur. Within a split second everything returned to normal and I went straight back to sleep. In the morning I told Pat, not entirely sure whether it was a dream. Unfortunately it wasn’t - there had been an earthquake which at the time of writing has  killed 20 people in Abruzzo, the region immediately south of us. 10, 000 homes have had to be evacuated. No damage here, fortunately. Pat, meanwhile had slept through the earthquake - she puts it down to the earplugs she wears to block out my snoring. But I didn’t hear a noise, was just aware of movement. So why didn’t the earth move for Pat? Please don’t answer that question!