The entrance to the Empire Cave, as seen on the left, partially hidden behind the overgrown thicket of bushes, and protected by a cement wall. The view is looking up Cave Gulch, with the small stream on the left and Kresge and Porter colleges up the hill to the right. The University has tried to cover the entrance to the cave several times with cement and steel structures, only to have it dynamited each time by irate cave enthusiasts . Several other caves occur in the area, with entrances across the creek.
Caves are common worldwide, wherever karst terranes are found.
As discussed at the sinkole site, caves form when acidic groundwater disolves the CaCO3 marble. If the rocks occur above the water table, the CO2 will escape into the atmosphere, as when any bottle of soda is opened. Therefore, it is thought that caves are formed below the water table, and can only be entered when geologic events occur that lower the water table. In the Empire Cave case, uplift of the Santa Cruz mountains, along with the marine terraces, and erosion of Cave Gulch may have played important roles in lowering the water table. The image on the right looks down the entrance to the Empire Cave.