Wireless monitoring for cliff stabilization at La Clua (Pre-Pyrenees, Spain)

La Clua is a village at the foot of a conglomerate cliff (Pre-Pyrenees, Spain), eventually af-fected by rockfalls. After last big event, in 2009, that affected a house of the village, a rope net was installed to protect the village. In order to obtain information about the performance of the protecting net, but also to gain knowledge on the triggering mechanism a wireless mon-itoring system was installed. The system is equipped with sensors (4 crackmeters, 2 biaxial tiltmeters, 2 rope tension load cells and 2 thermistors) that are measuring the changes on two unstable boulders (one protected with the net, the other not). Sensors are connected to wire-less dataloggers, installed next to the sensors and send data to the gateway. In this site, gate-way is located 250 m far from the furthest logger, but thanks to the long range technology of the system, loggers can be up to several km far from the gateway and the data which is pushed to an internet server every 15 minutes. Preliminary results show that no relevant movements have been observed in the boulders, since February 2016. Only some slight changes of around 0.15º have been observed after heavy rainfall events in spring.Postprint (published version

Estimación de la magnitud de procesos torrenciales mediante diferentes técnicas geomáticas: aplicación a la cuenca El Rebaixader (Pirineo Central)

Los procesos torrenciales como corrientes de derrubios o flujos hiperconcentrados pueden cambiar fuertemente la morfología de una cuenca vertiente, y las técnicas geomáticas son una herramienta ideal para determinar y cuantificar estos cambios topográficos. En la cuenca torrencial El Rebaixader se han aplicado láser escáner terrestre de larga distancia (TLS) y fotogrametría para crear diferentes modelos digitales de elevaciones , que se han comparado posteriormente entre ellos y con otros modelos existentes (por ejemplo mediante láser escáner aerotransportado). Las primeras experiencias de TLS indican que esta técnica, que se ha aplicado con éxito en macizos rocosos para desprendimientos, es más difícil de utilizar en una cuenca vertiente donde afecta considerablemente la vegetación y las superficies irregulares e húmedas. Por otra parte, la fotogrametría ha podido aplicar sin grandes problemas. Finalmente, se ha podido estimar una tasa de erosión de aproximadamente 15000 m3 por año entre 1975 y 2012, que coincide bien con los datos medidos entre 2009 y 2012 en la auscultación in-situ.Postprint (published version

Wireless monitoring for cliff stabilization at La Clua (Pre-Pyrenees, Spain)

La Clua is a village at the foot of a conglomerate cliff (Pre-Pyrenees, Spain), eventually af-fected by rockfalls. After last big event, in 2009, that affected a house of the village, a rope net was installed to protect the village. In order to obtain information about the performance of the protecting net, but also to gain knowledge on the triggering mechanism a wireless mon-itoring system was installed. The system is equipped with sensors (4 crackmeters, 2 biaxial tiltmeters, 2 rope tension load cells and 2 thermistors) that are measuring the changes on two unstable boulders (one protected with the net, the other not). Sensors are connected to wire-less dataloggers, installed next to the sensors and send data to the gateway. In this site, gate-way is located 250 m far from the furthest logger, but thanks to the long range technology of the system, loggers can be up to several km far from the gateway and the data which is pushed to an internet server every 15 minutes. Preliminary results show that no relevant movements have been observed in the boulders, since February 2016. Only some slight changes of around 0.15º have been observed after heavy rainfall events in spring

Wireless landslide monitoring: triggering factors and dynamic behaviour

Monitoring is fundamental for the prediction and analysis of landslide triggering factors and dynamic behaviour and major issues in the hazard assessment and risk mitigation. Wired monitoring systems have traditionally been used in landslide monitoring. However, wireless technologies are escalating in this field as a consequence of their multiple advantages against standard wired systems, such as their versatility and lower power consumption. Wireless monitoring is a perfect solution for the acquisition of data on geological processes in remote areas where power availability is scarce and the position of the sensors is often a critical issue due to the landscape conditions. In this paper, a complete landslide wireless monitoring system is described within the context of a successful case study in the Central Pyrenees, Spain. The Rebaixader constitutes a typical high mountain catchment where landslides and torrential processes occur with a sub-annual frequency. Rainfall is the principal triggering factor of the type of landslides occurring at the Rebaixader (debris flows), but the specific details of the geotechnical mechanisms that originate the events is still not clear. In order to increase the knowledge on the processes occurring at the catchment, it was equipped with a Loadsensing network for the monitoring of triggering factors and a Spidernano Seismic Remote Unit for the acquisition of the ground vibration generated by the moving mass. The Loadsensing sensor network incorporates seven nodes provided with wireless communication capabilities, showing ultra-low power consumption and long-range communication. Digital, pulse and voltage sensors are connected to these nodes in order to monitor soil water content, soil water potential, snow height, 5-minute rainfall intensity, and air temperature and humidity. The sensor nodes communicate in a multi-hop fashion to deliver the information into a gateway, placed 500 m away in the line of sight, with two repeaters placed along the line. The gateway offers enhanced computational and storage capabilities, as well as 3G modem communication to the data centre. Spidernano is a seismic remote unit (SRU) equipped with GPS clock discipline, which is connected to the Gateway via Ethernet cable. It was connected to three 1D geophones recording simultaneously the ground vibration generated by the passage of the debris-flow mass near the geophones. It has a low power consumption (0.5 W), specially adapted for field campaigns or permanent monitoring. The recordings revealed that debris-flow occurrence can be detected by ground vibration signal and the approach of the flowing mass can even be detected before the arrival. Data acquired by Loadsensing provided valuable results on the understanding of the failure and post-failure mechanisms such as the infiltration patterns of water into the soil before and during the events. All these achievements are promising results for the application of low power wireless technologies not only for standard landslide monitoring but also for landslide early warning systems.Postprint (published version

Wireless landslide monitoring: triggering factors and dynamic behaviour

Monitoring is fundamental for the prediction and analysis of landslide triggering factors and dynamic behaviour and major issues in the hazard assessment and risk mitigation. Wired monitoring systems have traditionally been used in landslide monitoring. However, wireless technologies are escalating in this field as a consequence of their multiple advantages against standard wired systems, such as their versatility and lower power consumption. Wireless monitoring is a perfect solution for the acquisition of data on geological processes in remote areas where power availability is scarce and the position of the sensors is often a critical issue due to the landscape conditions. In this paper, a complete landslide wireless monitoring system is described within the context of a successful case study in the Central Pyrenees, Spain. The Rebaixader constitutes a typical high mountain catchment where landslides and torrential processes occur with a sub-annual frequency. Rainfall is the principal triggering factor of the type of landslides occurring at the Rebaixader (debris flows), but the specific details of the geotechnical mechanisms that originate the events is still not clear. In order to increase the knowledge on the processes occurring at the catchment, it was equipped with a Loadsensing network for the monitoring of triggering factors and a Spidernano Seismic Remote Unit for the acquisition of the ground vibration generated by the moving mass. The Loadsensing sensor network incorporates seven nodes provided with wireless communication capabilities, showing ultra-low power consumption and long-range communication. Digital, pulse and voltage sensors are connected to these nodes in order to monitor soil water content, soil water potential, snow height, 5-minute rainfall intensity, and air temperature and humidity. The sensor nodes communicate in a multi-hop fashion to deliver the information into a gateway, placed 500 m away in the line of sight, with two repeaters placed along the line. The gateway offers enhanced computational and storage capabilities, as well as 3G modem communication to the data centre. Spidernano is a seismic remote unit (SRU) equipped with GPS clock discipline, which is connected to the Gateway via Ethernet cable. It was connected to three 1D geophones recording simultaneously the ground vibration generated by the passage of the debris-flow mass near the geophones. It has a low power consumption (0.5 W), specially adapted for field campaigns or permanent monitoring. The recordings revealed that debris-flow occurrence can be detected by ground vibration signal and the approach of the flowing mass can even be detected before the arrival. Data acquired by Loadsensing provided valuable results on the understanding of the failure and post-failure mechanisms such as the infiltration patterns of water into the soil before and during the events. All these achievements are promising results for the application of low power wireless technologies not only for standard landslide monitoring but also for landslide early warning systems

Wireless landslide monitoring: triggering factors and dynamic behaviour

Monitoring is fundamental for the prediction and analysis of landslide triggering factors and dynamic behaviour and major issues in the hazard assessment and risk mitigation. Wired monitoring systems have traditionally been used in landslide monitoring. However, wireless technologies are escalating in this field as a consequence of their multiple advantages against standard wired systems, such as their versatility and lower power consumption. Wireless monitoring is a perfect solution for the acquisition of data on geological processes in remote areas where power availability is scarce and the position of the sensors is often a critical issue due to the landscape conditions. In this paper, a complete landslide wireless monitoring system is described within the context of a successful case study in the Central Pyrenees, Spain. The Rebaixader constitutes a typical high mountain catchment where landslides and torrential processes occur with a sub-annual frequency. Rainfall is the principal triggering factor of the type of landslides occurring at the Rebaixader (debris flows), but the specific details of the geotechnical mechanisms that originate the events is still not clear. In order to increase the knowledge on the processes occurring at the catchment, it was equipped with a Loadsensing network for the monitoring of triggering factors and a Spidernano Seismic Remote Unit for the acquisition of the ground vibration generated by the moving mass. The Loadsensing sensor network incorporates seven nodes provided with wireless communication capabilities, showing ultra-low power consumption and long-range communication. Digital, pulse and voltage sensors are connected to these nodes in order to monitor soil water content, soil water potential, snow height, 5-minute rainfall intensity, and air temperature and humidity. The sensor nodes communicate in a multi-hop fashion to deliver the information into a gateway, placed 500 m away in the line of sight, with two repeaters placed along the line. The gateway offers enhanced computational and storage capabilities, as well as 3G modem communication to the data centre. Spidernano is a seismic remote unit (SRU) equipped with GPS clock discipline, which is connected to the Gateway via Ethernet cable. It was connected to three 1D geophones recording simultaneously the ground vibration generated by the passage of the debris-flow mass near the geophones. It has a low power consumption (0.5 W), specially adapted for field campaigns or permanent monitoring. The recordings revealed that debris-flow occurrence can be detected by ground vibration signal and the approach of the flowing mass can even be detected before the arrival. Data acquired by Loadsensing provided valuable results on the understanding of the failure and post-failure mechanisms such as the infiltration patterns of water into the soil before and during the events. All these achievements are promising results for the application of low power wireless technologies not only for standard landslide monitoring but also for landslide early warning systems

Estimación de la magnitud de procesos torrenciales mediante diferentes técnicas geomáticas: aplicación a la cuenca El Rebaixader (Pirineo Central)

Los procesos torrenciales como corrientes de derrubios o flujos hiperconcentrados pueden cambiar fuertemente la morfología de una cuenca vertiente, y las técnicas geomáticas son una herramienta ideal para determinar y cuantificar estos cambios topográficos. En la cuenca torrencial El Rebaixader se han aplicado láser escáner terrestre de larga distancia (TLS) y fotogrametría para crear diferentes modelos digitales de elevaciones , que se han comparado posteriormente entre ellos y con otros modelos existentes (por ejemplo mediante láser escáner aerotransportado). Las primeras experiencias de TLS indican que esta técnica, que se ha aplicado con éxito en macizos rocosos para desprendimientos, es más difícil de utilizar en una cuenca vertiente donde afecta considerablemente la vegetación y las superficies irregulares e húmedas. Por otra parte, la fotogrametría ha podido aplicar sin grandes problemas. Finalmente, se ha podido estimar una tasa de erosión de aproximadamente 15000 m3 por año entre 1975 y 2012, que coincide bien con los datos medidos entre 2009 y 2012 en la auscultación in-situ

Estimación de la magnitud de procesos torrenciales mediante diferentes técnicas geomáticas: aplicación a la cuenca El Rebaixader (Pirineo Central)

Los procesos torrenciales como corrientes de derrubios o flujos hiperconcentrados pueden cambiar fuertemente la morfología de una cuenca vertiente, y las técnicas geomáticas son una herramienta ideal para determinar y cuantificar estos cambios topográficos. En la cuenca torrencial El Rebaixader se han aplicado láser escáner terrestre de larga distancia (TLS) y fotogrametría para crear diferentes modelos digitales de elevaciones , que se han comparado posteriormente entre ellos y con otros modelos existentes (por ejemplo mediante láser escáner aerotransportado). Las primeras experiencias de TLS indican que esta técnica, que se ha aplicado con éxito en macizos rocosos para desprendimientos, es más difícil de utilizar en una cuenca vertiente donde afecta considerablemente la vegetación y las superficies irregulares e húmedas. Por otra parte, la fotogrametría ha podido aplicar sin grandes problemas. Finalmente, se ha podido estimar una tasa de erosión de aproximadamente 15000 m3 por año entre 1975 y 2012, que coincide bien con los datos medidos entre 2009 y 2012 en la auscultación in-situ