Palm Damage unknown source

[cbarnett421]

I have lived with my palms since buying this house in 2008 (San Diego), last summer I noticed a small gouge at the base, I immediately thought the kids had done i and moved on.  Around 3 months ago another appeared, and then another and another, they are appearing quicker and larger than initially.   I noticed a slightly brown patch just above too.  Does anyone know what is doing this?  I don't have sprinkers (I have drippers), weather has been worse than I've seen here a lot of rain, and very cold this winter.  The leaves have a little yellow but they're mostly green and not frazzled.   I do have a dog but the dog has been with me since 2010, so nothing has changed there. No one has been up the tree with spikes,  nothing has been tied to it.  Any help would be appreciate, I don't know what to do or how to save it.   

I'm from the UK, my palm knowledge is pretty  minimal, mine have have been happy since i've know them.   I would hate to lose them if there is something that could have been done.    They're within reach of the house should they topple.  

Thank you