Irrespective of what causes the damage (some might say velocity; and the actual damage can be estimated via intensity anyway), the point ( as I understand it) is that a magnitude 9.5 expends a certain amount of energy, and to expend the same energy budget by letting off 6.5 events means you would need a very large number of them. So given the choice between sitting through a 9.5 and sitting through a 6.5 every day for 73 years I would take the biggie and get it over with.