(Pacific City, OR) -- A second sink hole has appeared in the sand at Cape Kiwanda State Natural Area. The first sink hole formed in January. The Oregon State Parks Department closed the area around the sink hole and now they've extended that around the second sink hole. The first sink hole originally was around 20-feet wide and 15-feet deep. What's causing the sink holes isn't known. The area is made of sandstone and prone to erosion.