In Conza, the ruins of 41 years ago coexist with an ancient Roman city, Compsa, which had been hidden under houses, cellars, and streets until bulldozers dug to remove rubble after the quake.
as an aside, the article says tremblor, a common misspelling of temblor.
No, the ancient town was buried by building layer upon layer over the centuries. This is a quite normal process almost anywhere in the world, it was easier to build upon the foundations of existing buildings if they were sturdy enough than to completely remove them to start over with new foundations.
I had always heard this and only more recently learned that many civilizations for purposes of both sanitation (or more accurately, infestation) and materials science built out of material not far removed from mud bricks and when the house got bad you knocked it down, pulverized the bricks, spread it out on your property and possibly into the street (unless it was cobbled) and built on top. Over time doorsteps and streets went up and up. On the plus side, drainage improves over time, because the town keeps moving above flood stage. But hauling things into town gets a little harder every year too.
So an earthquake buried a Roman town, people built on top of the rubble, then another quake sent the rubble down the hill uncovering the ruins again?