Technology offers us some peace of mind that we can be warned if there are any environmental hazards, such as a flood or storm. Some events are easier to predict than others, but geohazard prediction should improve as technologies advance.
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Although those sensor networks have been relatively slow, they have still shown potential to monitor geohazards; from glacial floods to avalanches, volcanic eruptions, and storms.
Environmental sensor networks are devices containing sensors that are connected to a wireless network. These networks help us study environmental hazards, like landslides or floods. Sensor systems are used to monitor the geographic environment, whether at glaciers or the coast.
The sensor networks have been able to sense avalanches, landslides, volcanic activity, and even extreme weather events. Scientists also use these networks to assess the stability of slopes, helping them identify any landslides that could be triggered in the coming days by considering the weather forecast.
Water quality and air quality can also be monitored, where there could be toxic pollution in the environment that is harmful to animal and human life.
How Do They work?
To create an environmental sensor network, you need sensor nodules that send data through a radio network to a server, where the data can be retrieved. The sensors can be wired together, but most systems these days are wireless, which is less intrusive in the environment and more practical in most cases.
With data collected, they can be imported into a geographic information system (GIS) and integrated with satellite imagery to build a comprehensive picture of the area.
There are standards to adhere to when using the equipment. Martinez et al. (2004) advised that it is important to obtain a detailed understanding of the physical environment before deploying these systems. The equipment must be able to withstand the surroundings, where there may be adverse levels of dust, ash, vibrations, or temperatures. They should blend in with optimal size and weight to avoid interference from people or animals.
Ice, Snow and Floods
The Glacsweb project was the first to use ESN to study what was happening within a glacier.
The system had sensor nodes (probes and geophones), base stations and a UK-based server. The small sensors measured the pressure of the water, the deformation of the glacier, as well as its tilt and temperature.
It was used at Briksdalsbreen in Norway for three years from 2003, followed by Iceland. The sensor nodes recorded data that was communicated back to the base station on the glacier surface before being transmitted wirelessly to the server.
Though these systems would usually be consistent, there can be some problems. Some data gaps occurred due to communication issues between the sensors and the base station. A similar system called SEAMONSTER was used in Alaska’s Lemon Glacier to monitor glacial lake outburst floods, where other issues arose, such as the transmission of radio waves through the ice.
The PERMASENSE project at the Matterhorn mountain, located between Switzerland and Italy, measured rock instability and can be used to monitor snow atop mountain slopes for the detection of avalanches. Antolini et al. (2019) described an early warning system for avalanches and landslides, having tested the system out in a gulley that opened onto a road with a traffic light. The sensor network controlled the traffic lights and sent out SMS alerts.
Sensing Volcanic Activity
A more obvious hazard that is important to monitor is the activity of live volcanoes. Sensors record the seismicity (vibrations occurring in the ground), deformation of the rock surfaces, temperature changes and the expulsion of gases from the volcanic vents. Perhaps the most famous volcano of all is that of Mt. Vesuvius, where monitoring began in 1941.
Many dangerous volcanoes are monitored by the World Organization of Volcano Observatories (wovo.org), but not all of the world’s volcanoes are being monitored. According to a published study, developing countries may be the worst affected by this, as only 13% of active volcanoes in developing ountries are being monitored.
Applications at Sea
Sensor networks help to monitor extreme weather events such as storms and hurricanes. There is even potential integration with uncrewed autonomous vehicles – where these vessels can navigate remote, inhospitable regions, such as a hurricane or an Arctic glacier, without the need for humans to be aboard, reducing the possibilities of injuries or fatalities.
The idea that sensors can be used to sense incoming tsunamis, as some animals seem to do, has been suggested and could become further explored in the coming years. A tsunami warning system was developed in the Pacific Ocean in the 1990s, with expensive equipment that was since outdated.
Environmental sensor networks can arm environmental scientists with more data that helps to monitor hazards in remote, difficult-to-access locations, such as at the top of a snowy mountain peak to detect an avalanche or at a glacier to predict a flood. Further developments may see the improved prediction of a volcanic eruption or even a tsunami.
Due to complexities and technical challenges to address, these projects at large scales are few, which may involve power supply, communication, and security obstacles. It would be interesting to see if a globally integrated sensor system may one day be achieved so that we may foresee Earth’s hazards like never before.
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References and Further Reading
Antolini, F., Aiassa, S., & Barla, M. (2019). An Early Warning System for Debris Flows and Snow Avalanches. In National Conference of the Researchers of Geotechnical Engineering (pp. 338-347). Springer, Cham. http://dx.doi.org/10.1007/978-3-030-21359-6_36
Hart, J. K., Martinez, K. (2020). Sensor Networks and Geohazards. Treatise on Geomorphology. Elsevier. https://www.southampton.ac.uk/~km2/papers/2020/sns-and-geohazards.pdf
Martinez, K., Hart, J. and Ong, R. (2004) Environmental sensor networks. Computer, 37 (8), 50-56. https://doi.org/10.1109/MC.2004.91
R. S. J. Sparks, J. Biggs, J. W. Neuberg (2012). Monitoring Volcanoes. Science. 16 Mar 2012 Vol 335, Issue 6074 pp. 1310-1311. https://doi.org/10.1126/science.1219485