# Wireless Sensor Network-Based Rockfall and Landslide Monitoring Systems: A Review
## 3 Rockfall and Landslide Monitoring Based on WSNs
### WSN-Based Monitoring Systems
This means that periodic batteries replacement is required. Emphasis was placed mainly on three aspects of the WSN. First, the determination of the proper locations for the gateway and the sensors, based on experimental RSSI, SNR, and PRR (packet reception ration) values. Second, the selection of the phenomena to be monitored and of the type of sensor for each quantity to be measured. Third, the role of temperature on the measured inclination. During the experimental stage, the authors reported the occurrence of errors from the sensors for several reasons such as electrical problems, reduced battery lifespan and temperature and humidity effects. These problems created difficulties in the study, which led to the replacement of a part of the devices in one site. Table 2 reports a summary of the presented research works. The stage represents the status of the considered WSN, as in some cases, the works present only prototypal results or deal with fixed installations that are located in a geologic area for a longer time. The monitored element reports the particular type of structure and event that is monitored by each system. Table 3 provides geographical and geological information concerning the location of the research study, and witnessed events. \begin{table}
\begin{tabular}{c c c c} \hline
**Ref.** & **Year** & **Stage** & **Monitored Elements** & **Study Duration** \\ \hline (74) & 2012 & Laboratory prototype & Soil condition & Not specified \\ \hline (75) & 2021 & Fixed installation & Land displacement & Not specified \\ \hline (79) & 2022 & Fixed installation & Rockfall mesh barriers & 1 day \\ \hline (85) & 2022 & Fixed installation & \begin{tabular}{c} Rockfall mesh \\ Concrete barriers \\ Environmental parameters \\ \end{tabular} & July 2022—to date \\ \hline (87) & 2009 & Fixed installation & Rock mass tilting & Not specified \\ \hline (89) & 2019 & Portable test nodes & Rockfall pattern & Not specified \\ \hline (92) & 2017 & Not specified & Hillside landslide movement & Not specified \\ \hline (94) & 2016 & Fixed installation & \begin{tabular}{c} Land displacement \\ Environmental parameters \\ \end{tabular} & 9 months \\ \hline (96) & 2022 & Fixed installation & \begin{tabular}{c} Crack displacement \\ Rainfall \\ \end{tabular} & 9 months \\ \hline (97) & 2011 & Fixed installation & \begin{tabular}{c} Deep earth movements \\ Hydric characteristics \\ \end{tabular} & Not specified \\ \hline (98) & 2020 & Fixed installation & Soil moisture status & Not specified \\ \hline (99) & 2016 & Fixed installation & \begin{tabular}{c} Seismic movements \\ Soil moisture \\ \end{tabular} & Not specified \\ \hline (102) & 2018 & Fixed installation & \begin{tabular}{c} Rain-induced slope failure \\ Sediment disasters near expressways \\ \end{tabular} & \(1\) month \\ \hline (103) & 2011 & Laboratory prototype & Soil displacement & Not specified \\ \hline (105) & 2017 & Fixed installation & \begin{tabular}{c} Large crack displacement \\ Rainfall \\ \end{tabular} & Not specified \\ \hline (106) & 2023 & Fixed installation & \
\begin{tabular}{c} Land movements \\ Hydric characteristics \\ \end{tabular} & Not specified \\ \hline (107) & 2018 & Fixed installation & Rockfall barrier movements & 10 months \\ \hline (108) & 2023 & Fixed installation & Land displacement & 2 years \\ \hline (110) & 2016 &
\begin{tabular}{c} Fixed installation sensor nodes, fixed \\ and portable radar scanners \\ \end{tabular} & Rock mass movements & 3136 days \\ \hline (111) & 2018 & Fixed installation & Slope and river monitoring & 3 years \\ \hline \end{tabular}
\end{table} 
Table 2: Year, system stage, monitored hazards, and study duration.