11:30 〜 11:45
[S26-2-05] Seismogenic Layer within the Crust beneath Japanese Islands on the Japan Sea Side – application of JUICE catalog
Understanding the thickness of seismogenic layer is important parameter for the earthquake hazard assessment because this relates to the size of earthquakes caused by the active fault. We investigated the indexes D5 and D95 as the upper and lower limits of the seismogenic layer defined as the depth above which 5 % and 95 % of the whole crustal earthquakes occurred from the surface, respectively.
In previous study, we relocated hypocenters for 12 years between 2001 and 2012 from the NIED Hi-net catalog (hereinafter referred as “JUICE catalog", Yano et al. 2016) for high resolution hypocenter locations (Depth ≦40 km, M≧0.0). In order to satisfy Gutenberg-Richter magnitude-frequency relation, we extracted events with magnitude eaqual to or greater than 1.5 from the JUICE catalog. We then estimated the D5 and D95 using the same method as Matsubara and Sato (2015).
The general pattern of our results is consistent with similar studies of D10 and D90 (e.g. Matsubara and Sato, 2015; Tanaka, 2004; Omuralieva et al., 2012). For example, very deep D95 lies beneath the northern Hokkaido and northern Honshu and very shallow D95 extends along the belt-like volcanic areas. Moreover, this study enables to reveal that D5 and D95 have local variability of depth along active faults because we used the JUICE catalog, in which these hypocenters are confined into each cluster of seismicity and some active faults.
In previous study, we relocated hypocenters for 12 years between 2001 and 2012 from the NIED Hi-net catalog (hereinafter referred as “JUICE catalog", Yano et al. 2016) for high resolution hypocenter locations (Depth ≦40 km, M≧0.0). In order to satisfy Gutenberg-Richter magnitude-frequency relation, we extracted events with magnitude eaqual to or greater than 1.5 from the JUICE catalog. We then estimated the D5 and D95 using the same method as Matsubara and Sato (2015).
The general pattern of our results is consistent with similar studies of D10 and D90 (e.g. Matsubara and Sato, 2015; Tanaka, 2004; Omuralieva et al., 2012). For example, very deep D95 lies beneath the northern Hokkaido and northern Honshu and very shallow D95 extends along the belt-like volcanic areas. Moreover, this study enables to reveal that D5 and D95 have local variability of depth along active faults because we used the JUICE catalog, in which these hypocenters are confined into each cluster of seismicity and some active faults.