Lying on the Pacific Ring of Fire, the west coast of the US is no stranger to tectonic activity and tsunamis. The 2011 Tohoku-Oki earthquake and tsunami reached California’s shores, killing one person and caused $100 million worth of damage, according to the California Geological Survey. The recently revised tsunami hazard area maps are a testimony to the vulnerability of the US West Coast to tsunamis.
GIS in predictive mitigation
The Pacific Northwest Seismic Network lists tsunami hazard area maps as the first step in the development of effective evacuation plans for communities at risk. Midresolution land-cover data is used to estimate and compare community exposure to tsunami-hazards. This approach could be valuable in determining where to allocate disaster response and relief resources over large areas when time does not allow for detailed socioeconomic analysis. Dasymetric mapping techniques are also used to better map population exposure to tsunami hazards. Their use is not restricted to covering disasters caused by tsunamis alone, but can also be applied to several other scenarios.
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Location technology in search and rescue
While GIS and mapping do help with the ‘where’, a vital constituent of any search and rescue operation is time. It is here that disruptive location technologies play a part. Besides obvious solutions like GNSS, further growth in sensor technology and methods for detecting or calculating the geographical position of a person, a mobile device, or other moving objects has seen significant progress.
According to a 2019 report by the International Telecommunication Union (ITU), “The rapid spread of supporting digital infrastructure and devices – such as wireless broadband networks, smartphones and cloud computing – has created the foundation for the application of disruptive technologies for disaster management.”
One of the biggest difficulties that lies with post disaster rescue efforts is the restricted line of sight. What if GNSS were not available or were inappropriate? Limited indoor operation and, of course, positioning errors are well-known caveats associated with it. One way of getting around positioning errors is by using remedies like Differential GPS and Assisted GPS. But that still doesn’t remedy its limited indoor operation and since highest accuracy requires line-of-sight from the receiver to the satellite, GNSS does not work very well in an urban environment, under thick canopies, underwater, under bridges, etc. (GPS Application in Disaster Management: A Review).
This is where wireless sensor networks come in. Often, the search and rescue team’s work environment is highly dynamic. As such, Wireless Standard Networks (WSN) are an effective way to intervene. The key components of WSN are sensors, radio nodes, and a WLAN access point evaluation software. Bluetooth can also be used on similar principles to detect human presence and guide search and rescue operations.
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Location technology systems of Note
Increasingly, robots and drones are replacing humans in search and rescue operations owing to the fact that they can often fit into places humans can’t, can operate in hostile environments, require no sleep, their ability to even outperform humans in certain tasks, and most importantly, because of their replaceability.
New devices have been proposed that could ‘smell’ humans trapped under rubble. The devices are equipped with an NDIR carbon dioxide sensor which also senses the concentration of the gas, thereby detecting human presence. Similarly, Passive Infrared Sensors (PIR), which can detect a human via heat radiation, are also employed to locate those trapped.
Laser systems such as the Safire 380 HD FLIR enable accurate measuring of distance and direction to multiple targets and also for allowing the measuring of the height of obstacles in our area of operations over both land and sea.
On sea, UHF/VHF or marine beacons are used to track those in distress. ANGEL (Advanced Next-Generation Emergency Locator) is a second-generation beacon system developed by NASA that will also be deployed in future moon missions.
Not just professional search and rescue operators, volunteers too benefit from location technology where a portable tracker and a web application for displaying tracking information on electronic maps is used widely across the globe, according to Øyvind Hanssen of the Nord University, Norway. It is based on the Automatic Packet Reporting System (APRS), which is an open standard used by radio amateurs.
Other trackers may also be integrated into communication radios and use different technologies and infrastructures such as APRS, AIS (Automatic Identification System), Tetra (TErrestrial Trunked Radio – a digital radio communication system), cellphones, etc.
Going forward
With technology steadily advancing in the last few decades, the results show in both predictive mitigation and increased search and rescue effectiveness. Certainly, it takes time for cutting edge methods to become accessible to all, but GIS has already been widely embraced for preventive mitigation and as an aid to disaster response efforts.
The extensive availability of GNSS enabled handheld devices is unquestionably a welcome addition to search and rescue operations. But should the use of GNSS be compromised, there are now a vast array of technologies to rely on in emergencies.
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