What is the frequency of Fire From The Earth mini world-change?

Question

I'm waiting for this mini world-change to tame my Dragonling and earn the achievement, so how often it occur? Since that I even can't remember when was the last time it was active

Answer 1

There's not a known frequency of this world change. It can be activated by an unknown way or randomly (this is the official answer). I verified this on TibiaWiki.com.br and Tibia.fandom.com

[Theory] But now I will tell you a theory that I have, based on a single observation, this is not conclusive, so we need a lot more evidence to proof this. I noticed that my server was some weeks without this world change, and some days ago I killed the boss "Kerberos", in the next server save the Fire From the Earth world change was active, my theory is just that this world change is activated when a X Kerberos are killed (counter).

Answer 2

Dragonling can also be tamed at the Fury Gate and its own mini world-change, but let me inform you about my analysis of the frequency of the Fire From the Earth mini world-change. When it is active you can see the following message in the world board:

The volcano on Goroma sends its fiery message into the sky. A lot of creatures are flooding the lands together with its lava.

With a group of friends we have been keeping track of the World Board for our world for the past 157 days without missing any (this is ongoing) and the Fire From the Earth message has been active 18 of those days for an 11.47% chance (20/160 as last update, 12.5%). This does not seem very consistent with the reseach provided at the bottom of this TibiaWiki page that puts the chances at 19.57% with 91 out of 465 days.

But there is more to it! The event seems to activate in batches of days, appearing multiple days in a row.

• The 20 recorded active days from my data are split in 8 batches.
  • 3 single day events.
  • 2 two-days events.
  • 1 three-days events (one currently on streak).
  • 2 five-days event!

This makes me think there is something to trigger the end of this event. It could be related to the Fire from the Earth achievement, and the event would repeat itself if no one achieved it, or it could be something else but sadly I don't have more information on it.

I will update with the current on-going event streak, and will not trigger the Fire from the Earth achievement myself. At least not today. If you have more information, please provide a comment!
As an extra, the other answer suggests killing Kerberos might trigger the start of this event and this might be possible. Kerberos has been killed only once last week in my world and it was introduced on update 9.2 while Fire from Earth was introduced on 9.4.

UPDATE: Event that was active at time of writing finished into a 5 day event streak. 2 more Kerberos have been killed since then, one of them yesterday but today did not trigger. %s and list of streaks have been updated.