Listening for Landslides
The technology can be especially useful in flood-prone areas and hillsides villages constructed ad hoc.
"Earlier attempts at landslide warning systems had problems that the Loughborough group has solved. Like the new device, earlier versions converted acoustical energy to digital signals. Some operated on low-frequency sound, which travels farther before it attenuates. The main drawback was that this range of frequencies is in a band that's very noisy, and the systems returned too many false positives. But high-frequency devices struggled to capture the shear surface sounds because of attenuation and required off-site computing to handle the system's data-processing duties.
The Loughborough team sidestepped these problems with a high-frequency device that takes readings at a rate of 20 to 30 kilohertz. They limited the effect of attenuation by boosting the sound with as low tech a solution as it gets: gravel."