It can happen after 1886 with no other requirements, and has a mean time to happen of 96 months (8 years).
It kills 80% of all Native American minor POPs and adds native American minor as an accepted culture. On top of that it makes the event Apache Raiders impossible, and decreases militancy and consciousness by 10 for all native American minor POPs.
The renowned apache outlaw Geronimo has surrendered today, to Caption Henry Lawton of the army, with his small tattered band of apache men, women and children. With Geronimo's surrender the last shred of Apache resistance in the west has died out, and this once proud Indian nation can now be considered pacified. Geronimo will, many years from now, on his deathbed confess to his nephew, that he always regretted the decision to surrender.