Spatial and temporal evolution of b-values before large earthquakes in Taiwan

We investigate the spatial and temporal variations of b-values before twenty-three earthquakes with ML ≥ 6.0 in the Taiwan region from 1999 to 2009. We estimate the spatial distribution of b-values within a one-year period before the occurrence of investigated earthquakes. It shows that the epicenters of those earthquakes are located predominately in the regions with low b-values relative to the entire study area. In terms of temporal evolutions, the b-values are slightly lower during the year prior to the investigated earthquakes in comparison to the periods two to five years earlier. We propose that these anomalies may offer spatiotemporal constraints for the earthquake forecasting in Taiwan in the future.

► The spatial and temporal variations of b-values before large earthquakes in the Taiwan region are investigated.
► The epicenters of large earthquakes are located in the regions with low b-values.
► The b-values are slightly lower during the year prior to large earthquakes.