The best use for a big deep-seated landslide on Puget Sound is probably a forest. The next best use may be a relatively low-intensity public park. The northern day-use area at Camano Island State Park sits on a mid-slope bench, the contents of which began their jerky movement to the Sound hundreds or thousands of years ago. The uneven surface of the picnic area and the offsets in the parking lot suggest nothing has changed.
The head scarp is a high steep, forested slope that rises above the parking lot. Big drain pipes convey water from the land above (part of which is the park entrance road, but other parts of which are private homes) down to the bench, where hopefully it then gets captured and sent to the beach. Water is, after all, the grease on which these slides move, and the simplest way to slow their movement is to keep the water out. Of course, even that may be far from simple. The bench often slopes landward, making natural drainage tough, and slide movement can break pipes or otherwise disrupt drainage. And often the water is deeper groundwater, which doesn't lend itself to easy solutions.
These big slides often have portions that are more susceptible to movement than others - often, but not always, due to past or present drainage problems. The most active portion of this slide is the outside lane of the road down the bluff -- if it expands, access to the day-use area may become a lot more difficult. Or a lot more expensive.
But again, better a park. All too often, developers covet these benches for rows of million-dollar homes, and the developer is long gone by the time the foundations start cracking and the septic tank slides past the patio.
Other Big Landslides:
Perkins Lane, Seattle
Ledgewood Beach, Whidbey Island
Camano Head, Camano Island
Discovery Park, Seattle
Kopachuck State Park, Gig Harbor
Turnagain Heights, Anchorage
Termination Point, Hood Canal