Of course this node should be called False Second Impact because that's what the above descriptions describe.

The Second Impact is an event that happens in Neon Genesis Evangelion, which oddly enough comes after the First Impact and before the Third Impact.

Taking place on September 13, 2000 in Antarctica it was initiated by Seele to shrink Adam down to an embryo. The results of this procedure were known by Seele and Gendou Ikari and thus they took precautions. The Katsuragi expedition who were actually working on Adam didn't. The results were an explosion that could be seen from space, and the eventual loss of life, from both the flooding and the wars that followed, amounted to half the population of the earth.

What Seele told the world is known as the False Second Impact and is that a meteor hit the earth, this is like the False First Impact which is believe by many fans to be the death of the Dinosaurs, of course this is in no way correct.

Update 19/04/01

Called so because the catastrophe was the largest since an asteroid collided with Earth 4 billion years ago (First Impact/Giant Impact). It caused cataclysmic changes in the environment including floods, volcanic eruptions and a shifting of the Earth's axis. This, together with the civil conflicts that erupted on a world-wide scale shortly thereafter, erased half the world's population. Its cause was generally explained as a massive meteorite falling on Markam Mountain in Antarctica, but it was actually an artificial event -- caused by SEELE's and Gendou Ikari's attempt to reduce the 1st Angel, Adam, to embryo form before the other Angels awakened.

Source: The End of Evangelion : Glossary contained within The End of Evangelion - Theatrical Program.