If God,as you suggest, uses earthquakes as a punishment,the fact that there were no US earthquakes during slavery, must mean he approves of it (using your twisted rationale).
Slaves, male and female, you may indeed possess, provided you BUY them from among the neighboring nations. You may also BUY them from among the aliens who reside with you and from their children who are born and reared in your land. Such slaves YOU MAY OWN AS CHATTELS, and leave to your sons as their hereditary property, MAKING THEM PERPETUAL SLAVES. But you shall not lord it harshly over any of the Israelites, your kinsmen.
Where were the US earthquakes during the times of slavery?
THAT WOMAN IS A FRIGGIN' CRACKPOT.