Response of the PRISMA-YBJ Detectors to Earthquakes

Abstract

Interesting results are obtained using a setup with electron-neutron detectors (EN-detectors) developed for the PRISMA (PRImary Spectrum Measuring Array) project to study extensive atmospheric showers. A small installation of four EN-detectors (PRISMA-YBJ) has been in operation for three and a half years on the Earth’s surface in Tibet, 4300 m above sea level, constantly measuring the natural flux of thermal neutrons. Neutrons are produced in soil during (α, n)-reactions with naturally radioactive α-particles, mainly from the decay of radon and daughter heavy nuclides. The neutrons are thermalized in the medium and, once in equilibrium with it, become sensitive to its state. They then can indicate many geophysical processes in the crust, including earthquakes. Results illustrating the sensitivity of EN-detectors to earthquakes are considered.