HERD is an open citizen-science project developing an affordable infrasound sensor network to study whether communities can detect signals from tsunamis and volcanic eruptions before they arrive. Inspired by reports that elephants fled the 2004 Indian Ocean tsunami ahead of the waves, the project aims to listen for low-frequency pressure waves that travel through the atmosphere faster than tsunami waves.

Its HERD One sensor is in development and is designed to cost about $25, with a subsidized local price offered for residents of Thailand and coastal regions. The device uses a MEMS barometer, records 25 readings per second, includes GPS and connects by Wi-Fi. It is also intended to provide everyday weather-pressure readings. HERD plans to combine sensor data across locations, compare signals by timing and geography, and publish network data openly for researchers and communities. The project emphasizes that this is an experiment, not a certified alarm, and would complement rather than replace official warning systems. People can support the work through donations, sensor pre-orders, or a free waitlist.