The Kaiser effect, which is known as a stress memory effect, predicts that seismic events occur only when the previous maximum stress is exceeded. Therefore, the Kaiser effect has been applied for the estimation of the magnitude of “in situ” stress on crustal rocks in the community of geotechnical engineering (including forecasting earthquakes).

Geodetic observations have revealed that the time dependency of seismicity synchronized with inflation/deflation of a volcano is well explained by the Kaiser effect. However, the Kaiser effect has only been tested at room temperature in laboratories.

Researchers from Ehime University performed deformation experiments on natural olivine at high pressures and high temperatures via a state-of-the-art technology large-volume deformation apparatus combined with a microseismicity monitoring technique.

They successfully confirmed a stress memory effect (corresponding to the Kaiser effect in a broad meaning) in strongly deformed olivine at high pressures and high temperatures. The observed memory effect could be effective in the seismic zones of subducting slabs.

The findings are published in the journal Geophysical Research Letters.