What's the difference between imprecation and precation?

Imprecation

Definition:

(n.) The act of imprecating, or invoking evil upon any one; a prayer that a curse or calamity may fall on any one; a curse.

Example Sentences:

(1) Because the governments are relatively powerless to affect US policy toward them, they turn their energies to repressing and keeping down their own populations, with results in resentment, anger and helpless imprecations that do nothing to open up societies where secular ideas about human history and development have been overtaken by failure and frustration, as well as by an Islamism built out of rote learning and the obliteration of what are perceived to be other, competitive forms of secular knowledge.
(2) Mr Clegg could declare without irony that the Lib Dems belong in power, and at last lay to rest the lingering echo of David Steel's hubristic imprecation to go home and prepare for power.
(3) It begins in bravura style with sirens and a clap of thunder, and then – judging by the excerpts we hear – is thrillingly noisy and aggressive, indeed a return to the familiar Wu landscape of sinister soul samples, whiplash drums, and dire threats and imprecations, updated with the occasional reference to Harry Potter.
(4) As in the case of China, one does not have to regard Putin’s moves and motives favorably to understand the logic behind them, nor to grasp the importance of understanding that logic instead of issuing imprecations against it.
(5) EU gives Poland two months to scrap changes to its highest court Read more So far, Kaczyński has concluded he can ignore imprecations from Brussels or half-hearted protests from members with their minds on other matters.
(6) Of course they and my brother Don, despite my stuttered imprecations, drove through the night from Edinburgh.