At the start of my contribution to crisis mapping I tried to add earthquake:damage=collapsed_building to the objects that had yet only building=collapsed, but fact is that I find so much of those objects now, that I'm beginning to think it's not so necessary anymore. Am I wrong here? Also many camp_sites are missing this earthquake tag.
On the wiki Humanitarian OSM Tags page I think they mean that OSM mappers should use the tags on this wiki and then those would be converted to the Humanitarian Data Model at some point in time. Is that a correct assumption?
Mapping tools: HTC Touch Pro met osmtracker en Qstarz BT-Q818X Bluetooth GPS receiver
I dont really know the answer to your question. I've never mapped earthquake damaged buildings actually. For Japan there's still some missing roads and hospitals etc which you can do more valuable remote mapping work with.
From a quick glance the Humanitarian Data Background appears to give a more pragmatic useful overview of tags actually in use. Better to follow what other mappers are doing.
Great that this is made available here as I am also part of a simple crisis response software committee for our area.
I think that above being able to come up with a full running and perfectly fine software, it would be important to let the possible users get familiar with all the things that would make it run.
Say, the tags should be used properly just so there would be no problem with possibly making use of them in the future.