The novel “Summertide” by Charles Sheffield was published for the first time in 1990. It’s the first book of the Heritage Universe.

Humans have spread among the stars, slowly at first, with starships traveling at speeds lower than light, and then much more quickly using the Bose communication network that allows fast interstellar travel. In the course of their travels they met various alien species but also artificial structures millions of years old built by an unknown species.

Quake is a planet in the Dobelle system. There a particular configuration periodically causes the Summertide, an extremely violent seismic phenomenon. Quake and its twin planet Opal are joined by the Umbilical, one of the structures of Builders, the mysterious species that left so many artificial structures. Once every about 350,000 years this this phenomenon is even more violent and in occasion of this super Summertide some humans and aliens arrive on Quake to investigate but they’re not all what they seem.