Crack in the World

Just a bit of casual curiosity/thought experiment. Glaciologists sometimes place a line of poles across a glacier and photograph (and even plot the positions using GPS) through time, to show how the center of the flow moves more quickly than the edges.

Is there a place on Earth where a subduction zone could have poles driven into the plunging bedrock to directly and visibly measure the movement?

We would need a location with little overlying debris (hence eliminating the Mariana Trench, where there's a thick layer of sludge). This must also be a place where the subduction is proceeding quickly enough to produce a visible result in a few years (a typical rate is measured in centimeters per year, so that shouldn't be a problem) and at least somewhat steadily on this time scale.

I doubt there would be a scientific justification for this, but it would be cool to watch in time-lapse.