Reference Measurement Asphalt Seawall Vierhuizergat

Seawall Vierhuizergat in Lauwersoog
Extra sensor next to sensor7 at Seawall Vierhuizergat in Lauwersoog

To establish if the measurement poles, that are stabbed in the seawall through 60cm thick asphalt/tarmac layer, really show what is going on below the asphalt layer, we have mounted a reference sensor to the asphalt directly next to the most eastern (pole-)sensor (number 7)  

In the animation shown below., you see a scaled wire-model of the situation. The wire-box represents a 2 x 2 meter and 60cm  thick chunk of asphalt.  The measurement-pole in the middle anchors 180cm deep below the asphalt in the sand-layer.  

The animation shows the real movements measured by the sensores between 24-10-2012 17:30 en 19-10-2012 10:25 and is amplified 1000 times.

The animation shows that the measured movements  of both sensors are independent. The conclusion ot this experiment is that the movement asphalt  will have some influance on the measurement-pole but the measured-values of the measurement pole will mainly be a consequence of the movement of the sand-layer below the asphalt.