The use of earthquake rate changes as a stress meter at Kilauea volcano

Stress changes in the Earth's crust are generally estimated from model calc ulations that use near-surface deformation as an observational constraint. But the widespread correlation of changes of earthquake activity with stres s(1-5) has led to suggestions that stress changes might be calculated from earthquake occurrence rates obtained from seismicity catalogues. Although t his possibility has considerable appeal, because seismicity data are routin ely collected and have good spatial and temporal resolution, the method has not yet proven successful, owing to the nonlinearity of earthquake rate ch anges with respect to both stress and time. Here, however, we present two m ethods for inverting earthquake rate data to infer stress changes, using a formulation for the stress- and time-dependence of earthquake rates(6). App lication of these methods at Kilauea volcano, in Hawaii, yields good agreem ent with independent estimates, indicating that earthquake rates can provid e a practical remote-sensing stress meter.