South BR on Hill - Soil Movement

Moved into a house in S BR last year. We are on top of hill on the old Pleistocene Terrace mileish off Highland Rd. Truly the grade around our house is fairly steep for this part of the country.

There have been areas on the hill that have developed some significant cracks / soil movement... talking 4-6" deep and more movement in other areas. Surely there were trees on this slope prior to development, but the house is 50 yrs old.

1. Could this be from tree roots rotting and subsiding?
2. Recommendations on filling the cracks?
3. Recommendations on a professional in BR to come walk the area with me?

Thanks in advance. Been seeing this and worrying. Want to try and take steps to stop whatever is going on right now.