Krono by Charles L. Harness (Book, "Ex-Library", 1988)
Konteau, a Krono or time traveler, visits Deimos, Mar's smaller moon, on vacation, but soon faces the mystery of a whole boro's disappearance.
This new adventure takes place in a post-holocaust future sophisticated enough to relieve its population pressures with time travel but still full of atavistic cults. While the political scene rumbles with the contested selection of a new overlord, the loss of 5000 people in a timequake puts that time-site's original surveyor, Kron-Corps agent James Konteau, on the spot. It is typical of Harness's approach and sense of drama that Konteau's private memories and personal history get mixed up with his professional work in time and the ethical choices he must make against political leverage.