Game concept
Disaster
The game also links it as Disasters, Natural Disaster, Natural Disasters.
From the game's encyclopedia
Natural Disasters encompasses Floods and Earthquakes.
A Natural Disaster will result in the Death of many Characters in the affected Counties, and will further have a significant negative impact on Development, Popular Opinion, and Control in accordance with the disaster's severity.
The devastation caused by a Natural Disaster can be undone and the land revitalized with the completion of a Relief Great Project.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Disaster is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Natural Disasters encompasses Floods and Earthquakes." It covers Earthquake and Flood. The game also links it as Disasters, Natural Disaster and Natural Disasters. Patch 1.20.1.2, from game/common/game_concepts/tgp_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/tgp_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.