So how do we deal with “many”? In this instance, we feel like it should be “have,” not “has.” And yet the singular verb is correct. The sentence reads:
Many a town and village has been destroyed by earthquakes.
Here’s what I found:
You’re right to use the singular verb with “many a man.” Use singular pronouns to go with the construction also: “Many a man has lost his life at sea.” Burchfield describes this construction as “notionally plural” but singular in usage.
Authority: The New Fowler’s Modern English Usage edited by R.W. Burchfield. Clarendon Press: Oxford, England. 1996.
Someone else pointed out the rule on page 50 of Woe Is I that describes dealing with a compound subject. “When both halves of the subject are singular . . . so is the verb.”
Together, these rules confirm that the awkward sentence regarding those tragic towns and villages should read “has,” and not the word that would make better sense to our ears.