I live in northern virginia and there was an earthquake yesterday. It is said to have been the most powerful earthquake in 67 years on the east coast. The magnitude on richter scale was 5.9 and it lasted for 30 seconds. I live in a townhouse that was constructed in 2001. Luckily there was no damage at all. My question is, that can a townhouse collapse in earthquake? If so, what would be the magnitude and duration of quake? Let me know please. I am worried.