Who Should Fill a Sinkhole?
I have filled several of these when I lived in California, abandoned Old redwood septic tanks that finally rotted out, I would check into that. Natural or something like this, I would only use fill dirt / rock . cement would cost way more and wont stop it if it continues to grow. use caution if you do fill it as there may be several feet of the top that has not given way but a person walking on top could be enough for it to let go, a couple of 2"X8"X8' boards laid down to the hole is what we used after I went through 1. the home ones we filled were ~6' round and maybe 6'deep ,the Motel one was close to 20' and at least 8' deep