Proposal:Volcanic features

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Volcanic features
Proposal status: Draft (under way)
Proposed by: RicoZ
Applies to: type
Definition: Volcanic feautures and geology
Draft started: 2015-03-30

Originally proposed by MikeCollinson here: Talk:Tag:natural=lava#New proposal

Changes to approved natural=volcano

The approved proposal recommends to tag type and status of natural=volcano with type=* and status=*

This should be changed to use volcano:type=* and volcano:state=* - using type=* and status* for volcanoes would be deprecated.

Taginfo also lists volcano:last_eruption, volcano:number_of_eruptions and other possible subkeys of the volcano: namespace prefix which could be used.

Lava fields

  • natural=bare_rock ("rock" being used in the broad sense of a consolidated (solid) or unconsolidated (granular) layer). Could be also natural=scree
  • geological=* with =volcanic_lava_field or more specific tagging for solidified molten rock, pyroclastic mud flows. Currently used values:

The combinations natural={bare_rock,scree}}+{bare_rock,scree}={lava_flow,lava} are also in use.

Lava formations

Crater rims


Volcanic vents

A volcano can often be a complex and have multiple vents

Should there be a volcanic_vent:status=* to indicate active/inactive vents? Also vents may differ in what they are emitting so we could use volcanic_vent:type=* as well.


Updated October 2021: There is now an approved tag: natural=fumarole

natural=fumarole geological=volcanic_fumarole


natural=geyser geological=volcanic_geyser


Should we add the tag geological=volcanic_geyser to these nodes?
Rubund (talk) 09:14, 20 June 2015 (UTC)
  • Well. natural=geyser can also refer to non-volcanic geysers such as Cold-water geysers driven by CO2. One should be absolutely certain that it is a volcanic geyser before adding the tag. Rubund (talk) 09:20, 20 June 2015 (UTC)
Might be a good idea to use natural=geyser for all geysers and geological=volcanic_geyser for those of volcanic origin. I must admit CO2 geysers are new to me and I didn't investigate if and how they differ from volcanic geysers. RicoZ (talk) 10:28, 20 June 2015 (UTC)
What about natural=spring+geological=co2_geyser for cold-water CO2 geysers and natural=hot_spring+geological=volcanic_geyser for hot-water volcanic geysers? Rubund (talk) 12:26, 21 June 2015 (UTC)
Or maybe even better geological=geyser for both together with either geyser:type=volcanic or geyser:type=co2 which will better facilitate filtering out geysers. Rubund (talk) 12:37, 21 June 2015 (UTC)
Would be nice to have something even more generic that would also cover mudpots, fumaroles, mofettas and whatever else there is. The difference to springs is also hard to draw. RicoZ (talk) 17:38, 21 June 2015 (UTC)
We now have geological=volcanic_fumarole, geological=volcanic_mudpot, geological=volcanic_mofetta and geological=volcanic_geyser to refer to all the different types you mention. They can then all be used together with natural=hot_spring if desired. One could also introduce natural=geothermal_feature or what else do you have in mind? Rubund (talk) 19:00, 21 June 2015 (UTC)
I wonder if it's not easier/better to just use natural=fumarole, natural=mudpot, natural=geyser. They are pretty easily distinguishable "natural" features. Additionally, both fumarole and geysers all over the world have already been tagged like this. I would like to add a few other tags for defining the geyser characterisitics:
geyser:type=* to tell whether it's a volcanic, a cold-water co2, or a sea-water geyser
geyser:height=* to tell the usual height of the geyser
geyser:interval=* to tell the expected interval between every erruption
Additionally, using the same argument, maybe spring:type=hot is better after all. Hundreds (maybe thousands) of hot springs all over the world have been tagged as natural=spring. Changing them to natural=hot_spring would be non-backwards compatible changes, while simply adding the tag spring:type=hot could be done without even discussing every single node with the original contributor.
Are there any drawbacks that I don't see? Rubund (talk) 06:46, 22 June 2015 (UTC)
  • To me a geological=volcanic_geyser would be better called a lava fountain (geological=lava_fountain). Geysers are generally the result of geothermal activity rather than volcanic activity, directly. That is magma, or some other form of geothermal heat, heats groundwater to boiling point then causes water to be (explosively) ejected from the ground though a vent. If the water is ejected in pulses or eruptions it is a geyser but if the water flows out of the ground continuously it is a hot spring. If the water is boiling hot and bubbling due to the escape of steam then it is more like a pool of [boiling] water while if the water has been mixed with the surrounding earth to form mud it is a mud pool (mud-pot?), possibly also boiling hot, or could become a mud volcano, or geyser of mud rather than water. Fumaroles are vents that emit steam or other hot gases. These natural features can be of volcanic or other geothermal origin. Geological tags should be confined to rock formations and land related features rather than active water related features due to the geothermal activity that arises from ground water being heated to boiling point and turning into steam. As a result, I think the proposal for a geological=volcanic_geyser is ill-conceived and probably redundant. - Huttite (talk) 02:26, 3 January 2017 (UTC)


See also

These similar tags may have been proposed or may occur in the db.