These wires can detect the maximum depth according to the level selleck chemical Cabozantinib of the highest wire that has been broken by the flow and also make it possible to record the time of occurrence of the surge at Sunitinib c-Kit the instrumented Inhibitors,Modulators,Libraries site. However, after they have been broken, these devices cannot provide information about the height of further surges that follow the main one or about subsequent debris flows; they need to be reset each time after a debris flow.Figure 3.Wire sensors installed on a check dam [12].Photocells and infrared photobeam sensors Inhibitors,Modulators,Libraries can be utilized as a tool to detect debris flows [11]. The flowing mass interrupts the beams emitted by the sensors, making it possible to detect the passage of the wave.

Inhibitors,Modulators,Libraries If several Inhibitors,Modulators,Libraries sensors are installed at different heights at the same cross-section, it is also possible to approximately measure the peak flow stage.

Ultrasonic gauges Inhibitors,Modulators,Libraries are probably the most commonly used Inhibitors,Modulators,Libraries device for continuous monitoring of debris flow level [2, 13-15]. In addition to recording stage hydrographs, the ultrasonic sensors provide a way to measure channel erosion or aggradation at the site where they are installed.Ultrasonic sensors hung over the channel Inhibitors,Modulators,Libraries (Figure 4) measure the distance between the flow surface and the sensor itself, making it possible to record debris-flow hydrographs (Figure 5). These sensors are also used to measure the water level in rivers; however, the strong and rapid variability of flow height with time in debris flows requires much shorter logging intervals between two consecutive recordings (typically 1 second).

Radar and laser sensors have also been used, similarly to ultrasonic sensors, to measure flow depth and record stage Dacomitinib Inhibitors,Modulators,Libraries hydrographs of debris flows [16, 17].Figure 4.An ultrasonic sensor installed to monitor debris flows in an Brefeldin_A alpine stream.Figure 5.Debris flow hydrographs recorded at three monitoring sites in the same stream (Moscardo Torrent, Italy, 22 June 1996). The distances between the sensors are 144 m and 226 m, respectively.The passage of a debris flow wave induces strong ground vibrations and underground sounds, which can be recorded by different types of sensors (accelerometers, velocimeters, microphones) [13, 16, 18-20].

An important advantage of ground vibration sensors is that they can be installed at a safe distance selleckchem Crizotinib from the channel bed.

This overcomes an important shortcoming of other types of sensors, like the ultrasonic gauges, which need to be hung over the channel and thus are more prone to damage.The output signal of the seismic sensors (velocimeters) is a voltage proportional to the ground oscillation velocity [20]. Plots of the amplitude of the oscillations versus time are a suitable way to represent seismic sellckchem recordings of debris flows (Figure 6).Figure 6.Debris flow recording detected by ground vibration sensors: amplitude versus time (Moscardo Torrent, Italy, 22 June 1996).