spawn_earthquake_in_county_effect

spawn_earthquake_in_county_effect = {
	$COUNTY$ = { save_scope_as = epicenter_county }

	# Track globally for exclusivity and distribution
	start_situation = {
		type = natural_disaster_earthquake
		save_scope_as = situation
	}

	scope:situation ?= {
		set_situation_center_province = scope:epicenter_county.title_province
		add_to_global_variable_list = {
			name = ongoing_earthquakes
			target = this
		}
		set_variable = {
			name = fatalities
			value = 0
		}

		save_scope_value_as = {
			name = min_severity
			value = scope:epicenter_county.title_province.natural_disaster_earthquake_min_severity
		}
		save_scope_value_as = {
			name = max_severity
			value = scope:epicenter_county.title_province.natural_disaster_earthquake_max_severity
		}

		set_variable = {
			name = severity
			value = {
				add = {
					fixed_range = {
						min = 1
						max = 3
					}
					min = scope:min_severity
					max = scope:max_severity
				}
			}
		}

		set_variable = {
			name = epicenter_county
			value = scope:epicenter_county
		}

		situation_sub_region:disaster_area = { add_dejure_title_to_sub_region = scope:epicenter_county }
		# Add neighbours to sub_region
		scope:epicenter_county = {
			every_neighboring_county = {
				add_to_temporary_list = neighbouring_counties
				save_temporary_scope_as = neighbouring_county
				scope:situation.situation_sub_region:disaster_area = { add_dejure_title_to_sub_region = scope:neighbouring_county }
				# Cleanup for simpler debugging
				clear_saved_scope = neighbouring_county
			}
		}
		log_natural_disaster = "started"
	}
}

As written in game/common/scripted_effects/10_dlc_tgp_natural_disaster_scripted_effects.txt.