Strain budget accompanied with the 2016 Kumamoto earthquakes inferred from geodetic and geological data

Watanabe, Tsuyoshi ; Asamori, Koichi; Umeda, Koji*

We estimated the strain released by the 2016 Kumamoto earthquakes in the co- and post-seismic periods and the strain rate in the inter-seismic period using GPS data. Moreover, based on the active fault data, we estimated geological strain rate. From the results, we found that the shear strain as much as 7.10310 strain was released by the M7.3 earthquake and the strain released within the first about 2.5 months following the main shock was estimated to be one order of magnitude smaller than that of the co-seismic period. Furthermore, the recurrence interval was estimated to be 3100 years by comparing geological strain rate and co-seismic strain released by the main shock. These results were good agreement with the recurrence interval evaluated from the active fault data.