Titles/author of book series on civilization destroying wave sweeping the galaxy

Question

I read this book over 5 years ago, borrowed from a friend, but I believe it is quite a bit older.

A spaceship finds several planets where advanced civilizations have collapsed fairly suddenly, and where a nearby planet or moon has ruins of large, blocky structures that were never inhabited. Correlating locations and times shows that the Civilization Destroying Force sweeps through the galaxy like a wave front, The space farers gradually realize the ruins were built by a benevolent alien race hoping, in vain, to distract the attention of the destructive force wave from the nearby civilization.

I expect there were several sequels, and would be interested in finding the whole series.

Answer 1

This is almost positively "The Engines of God" by Jack McDevitt. The series is 'The Academy' (Priscilla Hutchins) novels.

[...] strange alien Monuments is discovered on Jupiter's moon Iapetus. Soon, others are found in several systems. And each monument is different; a large sculpture on Iapetus that archaeologist Richard Wald thinks is a self-portrait, mysterious square "moons" orbiting the first world found to have an intelligent (if pretechnological) civilization. But the most remarkable find is on the moon circling the world of Quraqua, a series of stone structures built to resemble nothing less than an entire city — but it was never a real city. The native Quraquat, themselves extinct, weren't the Monument-Makers, but explorations of their own ruins indicate that they did indeed come into contact with the strange species that inexplicably built this massive edifice, nicknamed "Oz" by its human discoverers, on their moon. Who were the Monument-Makers, why did they undertake these projects, and where are they now?]1