Nec: Landslide Predicted Only From Moisture Level In Earth, Sand


NEC: Landslide Predicted Only From Moisture Level in Earth, SandNEC Corp released a system that visualizes the risk of the collapse of a slope consisting of earth and sand in real time based on the amount of moisture contained in the earth and sand.
The system, "Landslide Disaster Sign Detection System," is expected to help municipalities promptly decide to issue an evacuation advisory/order for locals.


According to NEC, though there are various methods to judge the risk of landslide such as monitoring cameras, inclinometers and wire sensors, in many cases, the time gap between the detection of a sign and an actual collapse is short. Also, prediction methods using a simulation system incur a high cost.

The new system uses NEC's own data analysis technology that calculates four indicators required for the "Analytic Formula for Stable Slope," an analysis model for measuring the risk of landslide, by using only the amount of moisture contained in the earth and sand. The four indicators are (1) the weight, (2) adhesiveness and (3) friction of earth and sand and (4) water pressure in the earth.

NEC conducted verification tests of the technology in about 10 municipalities in Japan and commercialized it by using knowhow built up through the tests.

Sensor units are installed in slopes to measure the amount of moisture in the earth and sand, and measured data is transmitted to a cloud server via a small wireless relay station for analysis. Data on hourly rainfall and changes in the amount of moisture contained in earth and sand is accumulated in the cloud server so that real-time data can be compared with past data collected when a disaster actually occurred (or did not occur).

Sensor units are powered by batteries and can be continuously used for about two years. The small wireless relay station uses the 920MHz band, which does not require a license.

The reference price of the system including three sensor units and one wireless relay station per slope and design/installation costs is ¥6.9 million (initial cost, approx US$67,166, excluding tax) in addition to a monthly fee starting from ¥70,000 (excluding tax). NEC aims to sell 200 units of the system in three years.